Lyman 450 leaks - parts question

[johnh57]

With the addition of the Binford 3000 base heater the old 450 is starting to leak out of the bottom. It does ok at temps up to about 104 or so - but I left it alone for a while today and it drifted up to about 108. It started leaking. (temp probe taped to the top of the heater plate temps)

I decided I had some time before I needed it again so I stripped it down and boiled the body to get a better look at things.

The leak is from the bottom plug - but not from around the outside where the o-ring is. It's leaking around the turnshaft. The turnshaft has quite a bit of play in it. It has almost an 1/8" of vertical or axial play. You can push the shaft down far enough to where the lower head on the shaft almost clears the bottom of the plug. Is this normal?

I ordered a replacement assembly from Lyman as a precaution.

I'm wondering how the turnshaft is held into the bottom plug - is this something I can drive or push out, lap a surface and reinstall? or is keep the temp down to 100 ish the only cure? I'm using the Carnuba Red lube.

[Ed_Shot]

Bought a new "insides" kit for my 450 from Lyman about a year ago. Mine was leaking inside around the plunger. I just went and found the original factory parts I took out of it. The turnshaft just fits through the base and is held in by the pressure of being mounted and the normal pressure on the shaft from squeezing lube. I don't have a heater so when I remounted mine I put a piece of cardboard under the unit when I bolted it to the bench to act as a gasket against possible leaks. I'm real pleased with Lyman's rebuild kit.

[johnh57]

Thanks Ed - I think with to much pressure the shaft is actually slipping downward - I can see slight abrasion on the surface of the heater plate where the shaft turns.

I measured the recess of the shaft from the base of the body using a depth mic. Fully seated the shaft is 0.052" recessed from the bottom of the casting. The bottom plug is staked (about 20 times) and runs about .029" recessed into the casting. I'm thinking if I make a 0.050" ish stainless or nylon washer the diameter of the head of the shaft, that would hold the shaft up where it belongs. maybe.

[Ed_Shot]

John,
Sounds like a plan. I'm surprised that the force of pressure on the plunger squeezing the lube does not keep your shaft fully seated all the time. Bet your idea fixes it.

[EDG]

>>>I think with to much pressure the shaft is actually slipping downward - I can see slight abrasion on the surface of the heater plate where the shaft turns.<<<
It backs down when you reverse the screw to raise the piston.
When the piston is squeezing the lube the screw head has to pull against the base plug.
You can verify this by operating the screw with the lube sizer laying on it's side.

[johnh57]

Yes, I backed it out tonight. I'm not sure what an effective method of sealing it will be. Either the head of the shaft has to be better fitted to the base plug, or the cardboard and permatex solution. Thinking now of a flat rubber/neoprene gasket that is compressed between the base plug and the heater plate. I don't think an o-ring would carry the pressure unless a groove were turned in the base plug (or the heater plate) to trap the o-ring.

No problem turning the groove in the base plug, but I'd have to pop all the staking and, of course, that o-ring isn't leaking so far as I can tell.

I suppose one could remove the shaft and cut a small o-ring groove around the base of the shaft so it seals against the base plug.

[beagle]

A common problem with the Lymans. You can go nuts trying to repair it. I took a 2" square of heavy rubber, placed it over the bottom hole and lag bolted it down to a piece of 2 X 6. I have several sizers and the bench is drilled as to hole spacing. I just lag bolt one down when I need to change. This don't cure the problem but it sure keeps them from leaking out of the bottom./beagle

[johnh57]

Rather weak design. Im' thinking about some automotive gasket material cut the size of the recess in the bottom of the casting. I want it slightly proud of the casting so it compresses on the heater plate when I bolt the thing down. If it does leak around the stem it can't go anywhere.

I don't understand why the shaft is threaded almost all the way to the head. It would seem that if the last 3/8" were fit better to the bottom plug it would make a better seal. The die pistons are -0.002" from the die. They don't leak - much. Even a small 3/8" o-ring in the shaft would probably stop the problem.

If I had more sizers and had to swap out the mounts it might be an issue. Now if I can just keep it from bleeding all over the loading bench I'll be 'happy'

The plan:

Fit gasket material to the bottom of the plug set in place with permatex. The gasket will be the diameter of the recess in the casting for the bottom plug on the od, and a touch bigger than the hole in the bottom plug on the i.d. This should allow for future removal /repair/whatever of the shaft. Still planning on a thin spacer on the head of the shaft so it doesn't have the axial play that it does.

Make 0.003 spacer to hold the body of the casting 0.003 off of the heater plate (i.e. pop can). When this all sets up the gasket/permatex should be 0.003 proud of the bottom of the casting. This should allow for a bit of compression of the gasket when installing for use.

Bolt the housing and 0.003 shim plate down to the heater plate with a thin film of plastic (read saran wrap) over the heater plate to prevent any permatex ooze from gluing the housing down to the heater plate.

While the permatex is setting up. Chuck the shaft up in the lathe and machine a 0.056 inch deep by 0.064 wide groove in the shaft about 1/8" above the head of the shaft to receive a 3/8 o.d. o-ring. At 0.056 deep this should put about 20% squeeze on the o-ring.

cost - permatex about $4.50 for a 3 oz tube. Need less than 1% of the tube.
0-ring and a spare: about $1.00
9" x 36" x 1/64" gasket material: $2.50 at Ace Hardware.