Making a custom HW piston?

[gk10]

I would like to have a piston with a delrin ring on the rear of the piston, however l'm thinking that using a standard piston as a starting point isn't the best as they tend to be quite undersize towards the rear and they appear to be made from some fairly soft material.

My plan is to machine one up from scratch but l'm not sure of the best way of attaching the trigger latch rod.
The original seem to be splined and pressed in but could l thread it in and pin it in place?

I would also try to make it a bit lighter as well.

Anyone made their own piston before?

[JLB]

Thread it & Loctite. Shouldn't come adrift until lot's of heat applied then. You would also be able to experiment with different lengths of stroke just by replacing the piston rod.

John

[NickG]

I have made dozens of pistons from various materials , threaded rod the easiest, if you use your existing piston, once you have a rear bearing in it it won't contact anything anyway.

[gk10]

Thanks for the reply.
l've now been convinced to use thread and loctite.
My next question is how long should the thread length be and do l need to harden the latch rod at then end that engages the sear?

[Shed tuner]

Thanks for the reply.
l've now been convinced to use thread and loctite.
My next question is how long should the thread length be and do l need to harden the latch rod at then end that engages the sear?

Nick will have a better idea then me, but as a guide... depends the forces (mainspring) and how you are cutting the thread and the material used. well cut and accurate, into steel 5mm will do. Into ally, may 8mm. 10mm if not so well cut into ally.

yes to hardening - case only is fine.

[NickG]

The standard, is 1.5 X diameter , so 12.5, however I have gone as low as 10 mm into aluminium, with no problems