Tweaking a thermostat

[oneokie]

Have a Saeco #24 melting pot that is not getting hot enough to bottom pour.
I understand that this pot is the same as the old Lyman pot.
The adjusting ring set screw is frozen in place, so I am wondering if there are any other methods of tweaking that will raise the cut out temp of the thermostat?

[Baron von Trollwhack]

I take my Lees apart all the time to clean the contacts. I would guess all mechanical thermostats are similar. You may wish to check. BTW, I always listen to hear the pots cycling on and off as an indicator of temperature of current casting.
BvT

[454PB]

Yeah, if it has bimetal strips like the Lee thermostats, you can "tweak" them by bending.

[DLCTEX]

I have had to tweak the bimetal thermostats on electric heaters. A little bend can go a long way. If you go too far, bend it back. DALE

[Nardoo]

I tweaked the thermost on my Lyman mag 20 by turning the tiny little grub screw in the centre of the thermostat dial. Heated it up so good I melted my aluminium RCBS ladle in it. No joke.
Bought a cast iron Lyman ladle just tonight. Bottom pouring will again be reseved for little boolits.

Nardoo

[richbug]

I tweaked the thermost on my Lyman mag 20 by turning the tiny little grub screw in the centre of the thermostat dial. Heated it up so good I melted my aluminium RCBS ladle in it. No joke.
Bought a cast iron Lyman ladle just tonight. Bottom pouring will again be reseved for little boolits.

Nardoo


Which way did you turn it, and how much? I have a used one I just picked up, and it won't get hot enough to not leave wrinkled bullets. It is pretty much useless with pure lead...

I found the screw you were talking about.

[pstew]

Bringing this one back from the dead, but I'd like to know... which way to turn the screw?

[Echo]

Another thought - I have an old SAECO that gave up on me. I fixed it, with some help from my friends here on this board. The failure was due to excess heat on one connection caused by corrosion on the contact, causing the copper wire to overheat, deteriorate, and finally fail. This resistive connection was also causing me to have to turn the control up pretty high to get the heat I wanted. Maybe your furnace has the same problem. Easy to check by taking off the knob and unscrewing the cover plate to expose the wiring (WITH THE FURNACE UNPLUGGED, OF COURSE!). Be careful when you unscrew the connections, as you may disturb the bimetal strip assembly, that requires three hands to reinstall.

Mein zwei pfennig...

[montana_charlie]

Bringing this one back from the dead, but I'd like to know... which way to turn the screw?
I don't have the pot in question, but my Waage has one of those middle-of-the-shaft screws. I adjusted it so that when the pointer is set on '7' the melt is at 700 degrees. I was not trying to make the pot reach a higher temperature.

I used the pilot light to make adjustments, but it is counter-intuitve in operation.
With the melt at a 'too low' temp and the light out, I would turn the screw until the light came on. The melt kept getting cooler and cooler.

It appears the light comes on when the heat turns off. It's not what I expected, but I understand how, and why, it can operate that way.

Anyway, I started making adjustments when the light came on...and turning enough to make it go out.
Watching my thermometer, I got the control adjusted to my liking.

Yours may work in a similar manner...
CM

[Big Tom]

I just found an inexpensive (for me at least) way to control the temperature in my Lee 4-20 to about 5-10 degrees accuracy... A while ago, I built an external thermostat for my Bradley smoker and just realized, that with the correct thermocoupler, it can control temperatures up to 2000 F. So I got me a new thermocoupler for $5 and made it a banana plug connection and here we go.
The instructions and parts list for the thermostat can be found at http://www.susanminor.org/forums/showthread.php?t=315 - I paid about $75 but as I said, initially it was bought for the smoker and now found a second purpose.

As I said, the temperatures stays within 5-10 degrees F, the temperature selector on the Lee stays at "full" all the time as it is being switched on and off by the thermostat.

Tom