Lyman Mag 20. Thermostat adjustment?

[Nardoo]

I got a great used Lyman mag 20 pot but I guess I know why it was cheap now. The thing won't get hot enough. It will melt lead but even with the thermostat on10 it cycles off all the time before heating the alloy to a high enough temperature to cast.
I do not have a lead thermometer so I do not know what temperature I am getting. Is there a way to adjust the thermostat?


Thanks

[jawjaboy]

This might help.

http://www.lymanproducts.com/lymanproducts/Instruction%20Guide%2012.pdf

[newfoundlander]

Before sending the furnace back to lyman I would check the coil for scale and thermostat connections for connectivity. I purchased a used Mag 20 a few years back with the same problem. Once the scale was removed and the connections cleaned and secured averything was fine.

[Arnie]

Most of those thermostats have a small screw in the center of the shaft the knob is mounted on and you can adjust it so it will heat up more .Not sure which way you have to turn it .Arnie

[Marshal Kane]

Most of those thermostats have a small screw in the center of the shaft the knob is mounted on and you can adjust it so it will heat up more .Not sure which way you have to turn it .Arnie
Yes, the adjustment screw to the Mag 20 thermostat is located in the center of the shaft that the knob is mounted on. Pull the knob off and look into the shaft. It is very small so you will need something like a jeweler's screwdriver to turn it. Make sure you know your starting point so that you can return it to the same position if needed. Like Arnie, not sure which way you have to turn it.

Suggest you consider obtaining a good lead thermometer to remove any doubts on what your alloy temperature really is.

[Nardoo]

Thanks guys. Have our rondy on this weekend but will get onto it next week. Will advise of my results.

Nardoo

[ronbo]

Bought a new Lyman Mag 20 furnace this spring and have used it a few times. I was disappointed, it had frequent problems with spout freeze up. Checked the temperature with a casting thermometer today, the adjustment scale was off. To get the temperature to 750 had to set the knob to 9 or 10 top end of the knob scale. Removed the knob and adjusted the center small thermosat screw with a jewelers screwdriver. counter clockwise raises the temperature, clockwise lowers. Have it calibrated now so 7 is 700 degrees 7.5 is 750 and so on. Cured the problems with spout freeze.

[mold maker]

I've had the same problem with my Lyman 20lb pot ever since new. Thanks for the solution. I've scorched the pain off around the pour spout trying to pour in the Winter.
See an old dog can learn a new trick once in a while.

[bhn22]

The numbers on the dial are just reference points. They were never meant to represent a temperature.

[wv109323]

I tried to cast some bullets with my Lyman 20 over the weekend. In mid-session the lead almost froze up coming out of the bottom pour spout. It was so slow it was more of a drip than a pour. Of course the bullets were unacceptable with small wrinkles and round corners.
I shut down and let it cool off.
I found and corrected the following problems:
1.)The thermastat wiring that bolts to the prongs for the electrical cord were very loose. (the prongs have a nut that tightens against a wire terminal. The nuts had about two full turns before the terminals were tight.)
2.) All the spade terminals had heated and contracted so much over time that all were loose. I tighten the spades up with needle nose pliers so that they were in heavy contact when slide onto the terminals.
3.) The adjustment knob ( held on the shaft with an allen screw) was not centered on the arc of adjustment. I centered the knob so that the center of the arc of movement of the thermastsat shaft was in the center of the thermastat scale. The arc of the shaft allows the knob to travel well beyond the scale on both the high and low ends. ( Before adjustment the knob was indicating the thermastat was on the high end of the scale when actually the thermastat shaft was on the low end of the scale.)
I did not move the small thermastat adjustment under the knob.
When these were corrected I reheated the furnace and cast about 500 158 Keith style .358 bullets.
I hope this helps.