From Newsgroup: rec.crafts.metalworking

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot pedal. https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 1:50 PM, Snag wrote:

-a I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for , it's lower than the setting . Not an earth shaking problem as I have never
used the full amperage and I can control it now . Still , I'd rather get
the amperage I have it set at instead of guessing .

Pots can have different curves to their change in resistance on the
sweeper. For something like that I would think a linear curve would be
best, but it might be worth some research.

Its pretty easy to stick a meter on it and check total value and the
sweeper value. I'd probably do that first.

Then I might check to see if the pot is at max and min values at max and
min pedal travel. It might be possible to stick it in with the knob or
ring not lined up correctly. If that happens you can break the pot in
some cases by stomping on the pedal.
--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot pedal. https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably the ').pdf?' on the end it didn't like. The pedal looks just like the
Linemaster Varior used with my Hitachi TIG, I had to check that recently
and found the 50k pot was reading about 100k and not very smooth. Now
changed after locating a compatible direct replacement pot but still
something is not quite right with my TIG so it's going into the supplier
for testing. It took a while thinking about how to take the Varior pedal
apart as Linemaster indicates it can be mounted with the 2 screw holes provided but no information about how to take the pedal apart to do so.
In the end I figured out it had to have a spring loaded pivot pin like a
large watch strap pin and that proved to be so, easy once you know how.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

"Bob La Londe" wrote in message news:10dotbl$19jg3$1@dont-email.me...

On 10/27/2025 1:50 PM, Snag wrote:

I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for , it's lower than the setting . Not an earth shaking problem as I have never
used the full amperage and I can control it now . Still , I'd rather get
the amperage I have it set at instead of guessing .

Pots can have different curves to their change in resistance on the
sweeper. For something like that I would think a linear curve would be
best, but it might be worth some research.

Its pretty easy to stick a meter on it and check total value and the
sweeper value. I'd probably do that first.

Then I might check to see if the pot is at max and min values at max and
min pedal travel. It might be possible to stick it in with the knob or
ring not lined up correctly. If that happens you can break the pot in
some cases by stomping on the pedal.

--------------------------------------------
The common nonlinear pot is an audio volume control. https://www.planetz.com/potentiometer-tapers-graphed/
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

Snag <Snag_one@msn.com> wrote:

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .

Did the original pot give the amperage you set?

Does the new pot have the same mechanical travel as the original?

bob prohaska

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably the ').pdf?' on the end it didn't like. The pedal looks just like the
Linemaster Varior used with my Hitachi TIG, I had to check that recently
and found the 50k pot was reading about 100k and not very smooth. Now changed after locating a compatible direct replacement pot but still something is not quite right with my TIG so it's going into the supplier
for testing. It took a while thinking about how to take the Varior pedal apart as Linemaster indicates it can be mounted with the 2 screw holes provided but no information about how to take the pedal apart to do so.
In the end I figured out it had to have a spring loaded pivot pin like a large watch strap pin and that proved to be so, easy once you know how.

I got a 404 error from Jim's link . Did you find the page ? My welder
is an Everlast .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 28/10/2025 00:37, Snag wrote:

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine today >>> . Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used
the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot
pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably
the ').pdf?' on the end it didn't like. The pedal looks just like the
Linemaster Varior used with my Hitachi TIG, I had to check that
recently and found the 50k pot was reading about 100k and not very
smooth. Now changed after locating a compatible direct replacement
pot but still something is not quite right with my TIG so it's going
into the supplier for testing. It took a while thinking about how to
take the Varior pedal apart as Linemaster indicates it can be mounted
with the 2 screw holes provided but no information about how to take
the pedal apart to do so. In the end I figured out it had to have a
spring loaded pivot pin like a large watch strap pin and that proved
to be so, easy once you know how.

-a I got a 404 error from Jim's link . Did you find the page ? My
welder is an Everlast .

Try https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
, might have to copy and paste as formatting doesn't seem to like the ) .

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 5:56 PM, Bob La Londe wrote:

On 10/27/2025 1:50 PM, Snag wrote:

-a-a I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for ,
it's lower than the setting . Not an earth shaking problem as I have
never used the full amperage and I can control it now . Still , I'd
rather get the amperage I have it set at instead of guessing .

Pots can have different curves to their change in resistance on the sweeper.-a For something like that I would think a linear curve would be best, but it might be worth some research.

Its pretty easy to stick a meter on it and check total value and the
sweeper value.-a I'd probably do that first.

Then I might check to see if the pot is at max and min values at max and
min pedal travel.-a It might be possible to stick it in with the knob or ring not lined up correctly.-a If that happens you can break the pot in
some cases by stomping on the pedal.

This is a linear taper pot and I made sure I got it clocked correctly
before I locked the cog pulley down . I have another , I'll check
resistance values tomorrow .
The original pedal broke the pot because the overtravel stop screw
was missing . I repaired and used that pedal for a while . I asked
Everlast customer service for a replacement pot and they sent me a whole
new pedal - which is the one I just repaired . The old one still works
and is here somewhere I put it so I'd remember where it was ... but that
was 12 years ago , and my memory is the second shortest part of my
anatomy .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 7:54 PM, David Billington wrote:

On 28/10/2025 00:37, Snag wrote:

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine today >>>> . Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower >>>> than the setting . Not an earth shaking problem as I have never used
the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot
pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably
the ').pdf?' on the end it didn't like. The pedal looks just like the
Linemaster Varior used with my Hitachi TIG, I had to check that
recently and found the 50k pot was reading about 100k and not very
smooth. Now changed after locating a compatible direct replacement
pot but still something is not quite right with my TIG so it's going
into the supplier for testing. It took a while thinking about how to
take the Varior pedal apart as Linemaster indicates it can be mounted
with the 2 screw holes provided but no information about how to take
the pedal apart to do so. In the end I figured out it had to have a
spring loaded pivot pin like a large watch strap pin and that proved
to be so, easy once you know how.

-a I got a 404 error from Jim's link . Did you find the page ? My
welder is an Everlast .

Try https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
, might have to copy and paste as formatting doesn't seem to like the ) .

Still no joy . No matter , I wired this new pot exactly the same as
the old one . It works , just not calibrated to the amperage set on the display . I'll test it tomorrow to make sure it has the advertised values .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 6:49 PM, bp@www.zefox.net wrote:

Snag <Snag_one@msn.com> wrote:

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .

Did the original pot give the amperage you set?

Does the new pot have the same mechanical travel as the original?

bob prohaska

Yes and yes . Chances are slim it's a bad pot but I'll test it
tomorrow and test the other one - I bought two .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 28/10/2025 01:08, Snag wrote:

On 10/27/2025 7:54 PM, David Billington wrote:

On 28/10/2025 00:37, Snag wrote:

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine
today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's
lower
than the setting . Not an earth shaking problem as I have never
used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot
pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably
the ').pdf?' on the end it didn't like. The pedal looks just like
the Linemaster Varior used with my Hitachi TIG, I had to check that
recently and found the 50k pot was reading about 100k and not very
smooth. Now changed after locating a compatible direct replacement
pot but still something is not quite right with my TIG so it's
going into the supplier for testing. It took a while thinking about
how to take the Varior pedal apart as Linemaster indicates it can
be mounted with the 2 screw holes provided but no information about
how to take the pedal apart to do so. In the end I figured out it
had to have a spring loaded pivot pin like a large watch strap pin
and that proved to be so, easy once you know how.

-a I got a 404 error from Jim's link . Did you find the page ? My
welder is an Everlast .

Try
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
, might have to copy and paste as formatting doesn't seem to like the
) .

-a Still no joy . No matter , I wired this new pot exactly the same as
the old one . It works , just not calibrated to the amperage set on
the display . I'll test it tomorrow to make sure it has the advertised values .

When I click on the link it give me 404 and the URL is missing the
').pdf' at the end, I can add those characters manually and retry and it
finds the document.

Have you installed the pot in the correct orientation. The illustration
in the PDF looks like the Linemaster Varior I have and the pot could be installed so it is rotated if not careful and that could lead to it
going solid at extremes of travel possibly damaging the pot. The one
mine required was this one https://www.ebay.co.uk/itm/265047074017 which
is a direct replacement for the original, now obsolete, Clarostat pot.

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 8:18 PM, David Billington wrote:

On 28/10/2025 01:08, Snag wrote:

On 10/27/2025 7:54 PM, David Billington wrote:

On 28/10/2025 00:37, Snag wrote:

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine >>>>>> today
. Same 47k ohm rating as the original . But there's something weird >>>>>> going on , I'm not getting the amperage I set the dial for , it's >>>>>> lower
than the setting . Not an earth shaking problem as I have never
used the
full amperage and I can control it now . Still , I'd rather get the >>>>>> amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot >>>>>> pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably >>>>> the ').pdf?' on the end it didn't like. The pedal looks just like
the Linemaster Varior used with my Hitachi TIG, I had to check that >>>>> recently and found the 50k pot was reading about 100k and not very
smooth. Now changed after locating a compatible direct replacement
pot but still something is not quite right with my TIG so it's
going into the supplier for testing. It took a while thinking about >>>>> how to take the Varior pedal apart as Linemaster indicates it can
be mounted with the 2 screw holes provided but no information about >>>>> how to take the pedal apart to do so. In the end I figured out it
had to have a spring loaded pivot pin like a large watch strap pin
and that proved to be so, easy once you know how.

-a I got a 404 error from Jim's link . Did you find the page ? My
welder is an Everlast .

Try
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
, might have to copy and paste as formatting doesn't seem to like the
) .

-a Still no joy . No matter , I wired this new pot exactly the same as
the old one . It works , just not calibrated to the amperage set on
the display . I'll test it tomorrow to make sure it has the advertised
values .

When I click on the link it give me 404 and the URL is missing the
').pdf' at the end, I can add those characters manually and retry and it finds the document.

Have you installed the pot in the correct orientation. The illustration
in the PDF looks like the Linemaster Varior I have and the pot could be installed so it is rotated if not careful and that could lead to it
going solid at extremes of travel possibly damaging the pot. The one
mine required was this one https://www.ebay.co.uk/itm/265047074017 which
is a direct replacement for the original, now obsolete, Clarostat pot.

There is a tab that engages a slot to prevent rotation . With the
pedal all the way up I rotated the shaft to the internal stop then
backed it off a tiny bit then locked the cog pulley down . At the other extreme I still have just a tiny bit of rotation left on the pot .

I just ordered a pot just like the one in your link but several bucks cheaper and closer to my location - same mfr . The ones I have are
plastic shaft , and that was part of the reason I bought 2 . But at
least I can weld aluminum a lot easier now .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 8:18 PM, David Billington wrote:

On 28/10/2025 01:08, Snag wrote:

On 10/27/2025 7:54 PM, David Billington wrote:

On 28/10/2025 00:37, Snag wrote:

On 10/27/2025 6:09 PM, David Billington wrote:

On 27/10/2025 22:48, Jim Wilkins wrote:

"Snag" wrote in message news:10doltv$173eq$1@dont-email.me...

-a I got the new pot installed in the foot pedal to my TIG machine >>>>>> today
. Same 47k ohm rating as the original . But there's something weird >>>>>> going on , I'm not getting the amperage I set the dial for , it's >>>>>> lower
than the setting . Not an earth shaking problem as I have never
used the
full amperage and I can control it now . Still , I'd rather get the >>>>>> amperage I have it set at instead of guessing .
Snag

-------------------------------------------

Here is a sample wiring diagram and test procedure for a TIG foot >>>>>> pedal.
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf?

I had to search for that document as the link didn't work, probably >>>>> the ').pdf?' on the end it didn't like. The pedal looks just like
the Linemaster Varior used with my Hitachi TIG, I had to check that >>>>> recently and found the 50k pot was reading about 100k and not very
smooth. Now changed after locating a compatible direct replacement
pot but still something is not quite right with my TIG so it's
going into the supplier for testing. It took a while thinking about >>>>> how to take the Varior pedal apart as Linemaster indicates it can
be mounted with the 2 screw holes provided but no information about >>>>> how to take the pedal apart to do so. In the end I figured out it
had to have a spring loaded pivot pin like a large watch strap pin
and that proved to be so, easy once you know how.

-a I got a 404 error from Jim's link . Did you find the page ? My
welder is an Everlast .

Try
https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
, might have to copy and paste as formatting doesn't seem to like the
) .

-a Still no joy . No matter , I wired this new pot exactly the same as
the old one . It works , just not calibrated to the amperage set on
the display . I'll test it tomorrow to make sure it has the advertised
values .

When I click on the link it give me 404 and the URL is missing the
').pdf' at the end, I can add those characters manually and retry and it finds the document.

Have you installed the pot in the correct orientation. The illustration
in the PDF looks like the Linemaster Varior I have and the pot could be installed so it is rotated if not careful and that could lead to it
going solid at extremes of travel possibly damaging the pot. The one
mine required was this one https://www.ebay.co.uk/itm/265047074017 which
is a direct replacement for the original, now obsolete, Clarostat pot.

Here's a good link to the pedal wiring diagram and test procedure .

https://ssccontrols.com/uploads/Wiring-Diagram-C950-0725-for-47k-to-50k-Everlast).pdf
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

Here is the same link from a different search: https://ssccontrols.com/uploads/Wiring-Diagram-C925-0725-for-22k-to-25k-Everlast.pdf?srsltid=AfmBOopvbFQeeCPNhWE63NQxCg3ZhSjk4LdQApDLJtMQEMcqXloP4I2z

--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/28/2025 5:39 AM, Jim Wilkins wrote:

Here is the same link from a different search: https://ssccontrols.com/uploads/Wiring-Diagram-C925-0725-for-22k-to-25k-Everlast.pdf?srsltid=AfmBOopvbFQeeCPNhWE63NQxCg3ZhSjk4LdQApDLJtMQEMcqXloP4I2z

I found the link last night and printed the info .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/27/2025 3:50 PM, Snag wrote:

-a I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .

I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or may
not have something to do with output not matching set point . The other
pot measures 47k+- maxed out both ways . I'm having a hard time
understanding the different values , AFAIK these all use a single wiper
center contact so I should be getting the same reading from either side
when maxed out .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/28/2025 5:09 PM, Snag wrote:

On 10/27/2025 3:50 PM, Snag wrote:

-a-a I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for ,
it's lower than the setting . Not an earth shaking problem as I have
never used the full amperage and I can control it now . Still , I'd
rather get the amperage I have it set at instead of guessing .

-a I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or may
not have something to do with output not matching set point . The other
pot measures 47k+- maxed out both ways . I'm having a hard time understanding the different values , AFAIK these all use a single wiper center contact so I should be getting the same reading from either side
when maxed out .

I should note that the "other pot" mentioned above is the other new
one . The old one has readings so unstable you can't tell what they are .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/28/2025 3:23 PM, Snag wrote:

On 10/28/2025 5:09 PM, Snag wrote:

On 10/27/2025 3:50 PM, Snag wrote:

-a-a I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for ,
it's lower than the setting . Not an earth shaking problem as I have
never used the full amperage and I can control it now . Still , I'd
rather get the amperage I have it set at instead of guessing .

-a-a I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or may
not have something to do with output not matching set point . The
other pot measures 47k+- maxed out both ways . I'm having a hard time
understanding the different values , AFAIK these all use a single
wiper center contact so I should be getting the same reading from
either side when maxed out .

-a I should note that the "other pot" mentioned above is the other new
one . The old one has readings so unstable you can't tell what they are .

Has to be disconnected to get a good reading.
--
Bob La Londe
CNC Molds N Stuff

--
This email has been checked for viruses by AVG antivirus software.
www.avg.com
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From Newsgroup: rec.crafts.metalworking

Snag <Snag_one@msn.com> wrote:

On 10/27/2025 3:50 PM, Snag wrote:

I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or may
not have something to do with output not matching set point . The other
pot measures 47k+- maxed out both ways . I'm having a hard time understanding the different values , AFAIK these all use a single wiper center contact so I should be getting the same reading from either side
when maxed out .

Sounds like a bad pot to me. Exactly _how_ it's bad is confusing to
me as well. In any case, your expectation is correct and the pot is
likely the culprit.

My first thought was that something got stuck under the wiper, but
that would likely raise the resistance, not lower it. I can't come
up with a simple way to cause what you're seeing. In fact, it's hard
to come up with a _complicated_ way to obtain what you're seeing....

If you don't end up sending it back a dissection might be interesting.
The vendor should certainly replace it, or at least offer a credit.

Nice work!

bob prohaska


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From Newsgroup: rec.crafts.metalworking

On 10/28/2025 6:55 PM, Bob La Londe wrote:

On 10/28/2025 3:23 PM, Snag wrote:

On 10/28/2025 5:09 PM, Snag wrote:

On 10/27/2025 3:50 PM, Snag wrote:

-a-a I got the new pot installed in the foot pedal to my TIG machine
today . Same 47k ohm rating as the original . But there's something
weird going on , I'm not getting the amperage I set the dial for ,
it's lower than the setting . Not an earth shaking problem as I have
never used the full amperage and I can control it now . Still , I'd
rather get the amperage I have it set at instead of guessing .

-a-a I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or
may not have something to do with output not matching set point . The
other pot measures 47k+- maxed out both ways . I'm having a hard time
understanding the different values , AFAIK these all use a single
wiper center contact so I should be getting the same reading from
either side when maxed out .

-a-a I should note that the "other pot" mentioned above is the other new
one . The old one has readings so unstable you can't tell what they are .

Has to be disconnected to get a good reading.

It was unplugged from the welder . Checked at the plug per the
diagram and instructions I downloaded and printed last night . I have a
closer match to the original part on the way thanks to David Billington .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
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From Newsgroup: rec.crafts.metalworking

On 10/28/2025 6:59 PM, bp@www.zefox.net wrote:

Snag <Snag_one@msn.com> wrote:

On 10/27/2025 3:50 PM, Snag wrote:

I checked the resistance on that new pot . And I got some odd
readings ... I get 21k maxed out one side and 46k the other side .
Outside terminal to outside I get the 47k plus/minus . THis may or may
not have something to do with output not matching set point . The other
pot measures 47k+- maxed out both ways . I'm having a hard time
understanding the different values , AFAIK these all use a single wiper
center contact so I should be getting the same reading from either side
when maxed out .

Sounds like a bad pot to me. Exactly _how_ it's bad is confusing to
me as well. In any case, your expectation is correct and the pot is
likely the culprit.

My first thought was that something got stuck under the wiper, but
that would likely raise the resistance, not lower it. I can't come
up with a simple way to cause what you're seeing. In fact, it's hard
to come up with a _complicated_ way to obtain what you're seeing....

If you don't end up sending it back a dissection might be interesting.
The vendor should certainly replace it, or at least offer a credit.

Nice work!

bob prohaska

I have another that's a closer match to the original on the way . In
the meanwhile I can still use the machine if I need to . While I have
the pedal apart for I think I'll check the resistance of the leads in
the cable .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
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From Newsgroup: rec.crafts.metalworking

On Mon, 27 Oct 2025 15:50:07 -0500, Snag <Snag_one@msn.com> wrote:

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the >full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .

You didn't get a logarithmic pont instead of a linear, did you??
--- Synchronet 3.21a-Linux NewsLink 1.2

From Newsgroup: rec.crafts.metalworking

On 10/28/2025 11:16 PM, Clare Snyder wrote:

On Mon, 27 Oct 2025 15:50:07 -0500, Snag <Snag_one@msn.com> wrote:

I got the new pot installed in the foot pedal to my TIG machine today
. Same 47k ohm rating as the original . But there's something weird
going on , I'm not getting the amperage I set the dial for , it's lower
than the setting . Not an earth shaking problem as I have never used the
full amperage and I can control it now . Still , I'd rather get the
amperage I have it set at instead of guessing .

You didn't get a logarithmic pont instead of a linear, did you??

Linear taper , not audio .
--
Snag
I appreciated foreign cultures more
when they stayed foreign ...
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From Newsgroup: rec.crafts.metalworking

"Snag" wrote in message news:10dro32$2ilbc$1@dont-email.me...

It was unplugged from the welder . Checked at the plug per the
diagram and instructions I downloaded and printed last night . I have a
closer match to the original part on the way thanks to David Billington .
Snag
----------------------------------------

I received a lot of training and experience in accurate electrical
measurement while building precision industrial automated test equipment.
DVMs are handy but not highly dependable because of their uncertain
connector, lead and probe resistances. I check by shorting the probes
together before making a measurement.

The slower, better way is to pass a known and observed current through the Device Under Test (DUT) and measure the voltage drop across it with separate leads. Since less than a microamp passes through the voltage leads their resistance doesn't matter, if it's 10 K the error is 0.1% on a 10 Meg input. The cheap HF DVM is different, it's input resistance is 100 K.

A controlled constant current is better though the current source could be a power supply or battery and resistance as long as you measure it. A light
bulb is a pretty good current limiter because its current draw changes considerably less than a resistor's as voltage varies, the filament
resistance increases with temperature. The test light I made in the 70's to carry on my motorcycle from a wired tail/stop bulb socket gives around 1/2A through the tail filament and 2A for the stop. The current varies only a few tenths from 12 to 14V. The combined current is still 1A down at 2V. It was all I needed for the common repair of the time, filing and resetting the contact points.

For example 2 Amps causes an easily measured voltage drop of 2 milliVolts
when passed through 1 milliOhm, which is an inch of 10 AWG wire.

https://www.allaboutcircuits.com/textbook/direct-current/chpt-8/kelvin-resistance-measurement/

The measurement is between the two test clips closest to the DUT, whether
they are force or sense. If the force clips are closer to the DUT the leads out to the sense clips don't carry current. For convenience I use alligator clips on the current-carrying leads and smaller hook probes on the voltage sense leads.

Male pins recessed in a connector are difficult to probe without adding uncertain resistance. When it matters I make connectors to plug onto them
from hobby brass tubing or crimp connectors with the insulation removed and the sleeve compressed or expanded to fit.

Your strange pot may have internal damage, possibly a worn, corroded or
burned wiper contact that adds resistance unpredictably. I recently disassembled an inexpensive in-line car audio circuit breaker that had that problem, the brass(?) contacts were burned and blackened from one test of opening at rated current. It was little better than a fuse, it tripped correctly once, then heating from the burned contact made it trip at varying lower currents. I used it as a switch for battery load testing until it
failed completely, then performed an autopsy.

One of my large Variacs was available cheap because it had a bad spot, the brush had worn to its stop and no longer reached the winding there. The replacement would have cost over $100 if available (not) so I machined new brass holders for carbons from a Diesel repair shop.

Carbon brushes can be milled as long as the cut is inward from an edge, outward will chip the carbon off. The composition (resistivity) is different between brushes for 12V and 120V. They need to drop a few tenths of a volt
to reduce circulating currents through the windings they bridge short.


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From Newsgroup: rec.crafts.metalworking

"Snag" wrote in message news:10drosq$2iq7v$1@dont-email.me...

I have another that's a closer match to the original on the way . In
the meanwhile I can still use the machine if I need to . While I have
the pedal apart for I think I'll check the resistance of the leads in
the cable .
Snag
---------------------------

High resistance is most likely to be in connections, though wire can corrode if water gets in through insulation damage.

The current limited by a headlight bulb is enough to measure wire
resistance. It may be between 5 and 10 Amps so be careful how you measure
it. The 10A range on some DVMs has a time limit.

Electric water heater elements have resistance in the low tens of Ohms and
can serve as current limiters, with the advantage of screw terminals. Like light bulb filaments, heating element resistance changes with temperature so you can't measure the cold resistance and then compute current from voltage drop. The resistance change for Nichrome is low but you can't assume it's used.

I make homebrew current shunts to repair old ammeters with Constantan from Type T thermocouple wire.

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