idea for air pressure control of lyman 45

[Whiterabbit]

hi guys,

I wanna ping you guys for an idea I had for replacing the screw in a 45 with an air piston. I have an air piston with about a 3" reach.

I was thinking about removing the lead screw from my lyman 45, attaching the plunger to the end of my piston, then attaching it to the top of the lube barrel with a clamp. Add a regulator and more or less, I am done (maybe an air valve or two).


would this work? Do you think 80 PSI or less of air pressing on the lube column would be sufficient to get the lube flowing? I'm gonna combine this with a stick-on heater pad on a variac or dimmer to heat the 45 body, and between the two I should be able to have VERY fine control of bullet fill rate, and good uniformity.

I'm just not sure 100% if the piston can deliver sufficient pressure?

[shaune509]

Force = PSI x Piston Area
1"piston @ 80psi = 62.8#
1.5" piston @ 80psi = 141.4#
How will you control flow as the lube softens and wants to unload under the sizer?
Many questions as to how well it will work in real time.
Shaune509

[Whiterabbit]

sizer is mounted to a metal plate. I assume that'll keep the lube from squeezing out from under the plate.

Do you know if 140 pounds of force is typical for us?

[shaune509]

I don't think that the casting would take the strain. The 4" wrench used on the 45 to a 5/16 or 3/8 screw [not sure of the size] is way under 30# of force, yes the thread pitch aids the work. Think of this you only use about 80# to tighten the lug nuts on your car.
You are going to need to pulse the air to the cyl only when you need to add lube during the sizing, constant air will put lube into the die and on the floor every time there is no bullet in the die area as air is always trying to move the load, not like a screw that has a relaxing affect on the lube pressure as it flows.
Hope I have helped, personaly I would not try it on a 45.
Shaune509

[Whiterabbit]

don't get me wrong, I can use less pressure. MUCH less pressure! I wasn;t sure how much was needed since yes the screw puts so much mechanical advantage on the top piston. If I can get away with less, easy! turn the regulator down and off I go. I have an assortment of those, to go down as far as needed to make it work :).

I was worried first about the max needed. Wasn't sure if the force needed was anywhere close to max.