# Expanding mandrel for closed end items



## kazuma78 (Aug 4, 2015)

Has anyone here ever used an expanding mandrel or other type for closed end items? If you have, do you have any recommendations for one that works well? I would like to make some closed end items (Pens, key chains, fire piston) and so I am looking for solutions. Is there anything that can be used without bringing the tailstock up?


----------



## Sprung (Aug 4, 2015)

Josh, I have never turned anything closed end, but I plan to try some closed end pens (and maybe even some kitless pens) this winter. When I do, I'm planning to make myself some pin chucks in the various sizes that I'd need. I have a Taig Micro Lathe that I'll have finished restoring by winter, so it'll be easy for me to turn the metal to the diameters I need, but I believe you can also buy these from some places if you don't feel like trying to make them yourself.


----------



## Schroedc (Aug 4, 2015)

I've used the PSI one they make for doing 7mm stuff. It works reasonably well but of course you have to be gentle with your cuts or it'll want to deflect. I usually use it with the tailstock brought up to the end of the wood up until the very end when I do the final shaping and sanding of the closed end. I cheat a bit for fire pistons, I turn a shoulder on the piece I can grab in the jaws of my chuck and then cover the chuck marks with a collar like the duck call guys use.......


----------



## kazuma78 (Aug 4, 2015)

Sprung said:


> Josh, I have never turned anything closed end, but I plan to try some closed end pens (and maybe even some kitless pens) this winter. When I do, I'm planning to make myself some pin chucks in the various sizes that I'd need. I have a Taig Micro Lathe that I'll have finished restoring by winter, so it'll be easy for me to turn the metal to the diameters I need, but I believe you can also buy these from some places if you don't feel like trying to make them yourself.
> 
> View attachment 84692


 Ive seen those for sale but I am looking for someone with experience with them to see how well they function. I believe you would need to use the tailstock with one of those, and even then I have read that they can cause an un-uniform thickness of wood as they are turned because they dont sit completely straight. I dont know for sure so I would be interested in finding out from someone who has used them from here.


----------



## kazuma78 (Aug 4, 2015)

Schroedc said:


> I've used the PSI one they make for doing 7mm stuff. It works reasonably well but of course you have to be gentle with your cuts or it'll want to deflect. I usually use it with the tailstock brought up to the end of the wood up until the very end when I do the final shaping and sanding of the closed end. I cheat a bit for fire pistons, I turn a shoulder on the piece I can grab in the jaws of my chuck and then cover the chuck marks with a collar like the duck call guys use.......


 What do use as the innerds of the piston and rod? Id love to see a tutorial on how you make yours. I have an idea in mind of how I would try it, but a tried and true method would be even better.


----------



## Tclem (Aug 4, 2015)

I buy my own chucks from a guy on pen turners site. He will make them whatever size you want and I use a collet chuck to hold them


----------



## kazuma78 (Aug 4, 2015)

Tclem said:


> I buy my own chucks from a guy on pen turners site. He will make them whatever size you want and I use a collet chuck to hold them


 Can you post a picture of what his look like? Do they work pretty well?


----------



## Schroedc (Aug 4, 2015)

kazuma78 said:


> What do use as the innerds of the piston and rod? Id love to see a tutorial on how you make yours. I have an idea in mind of how I would try it, but a tried and true method would be even better.



As far as the innards of the cylinder, I make mine out of cocobolo or another oily rosewood, with a good sharp brad point bit the hole is nice and smooth so I don't line it with anything. for the rod, I've been using a ball starter rod from black powder rifles and turning a pocket in the end and 2 grooves for O-rings. Maybe next week I'll do a couple and do a tutorial....

Reactions: Like 3


----------



## kazuma78 (Aug 4, 2015)

Schroedc said:


> As far as the innards of the cylinder, I make mine out of cocobolo or another oily rosewood, with a good sharp brad point bit the hole is nice and smooth so I don't line it with anything. for the rod, I've been using a ball starter rod from black powder rifles and turning a pocket in the end and 2 grooves for O-rings. Maybe next week I'll do a couple and do a tutorial....


That would be great. I would love to see how you make them. Where do you get your ball starters from?


----------



## Schroedc (Aug 4, 2015)

kazuma78 said:


> That would be great. I would love to see how you make them. Where do you get your ball starters from?



Fleet farm (It's kind like Target for manly stuff up here, farm supply, hunting, household, etc...) I've got some brass rod laying in a drawer somewhere so maybe I'll machine a few for the next ones. If I do I'll post the steps in my tutorial....

Reactions: Thank You! 1 | Agree 1


----------



## Tclem (Aug 4, 2015)

kazuma78 said:


> Can you post a picture of what his look like? Do they work pretty well?


Yes they work well. They look just like what Matt posted


----------



## kazuma78 (Aug 4, 2015)

Tclem said:


> Yes they work well. They look just like what Matt posted


 And you get uniform thickness in the barrel when you turn it? Do you have a link for where you get yours?


----------



## duncsuss (Aug 4, 2015)

I think the ones Tony is talking about are the same ones I have -- from Rick Herrell (link) I have 2 of his that I use for custom fountain pens -- one the diameter that I drill barrels (8.25mm, since I tap threads to M9 x .75) and one the diameter that I drill caps (11.3mm, which I tap out to M12 x .75).

Rick requested drilled blanks from me so he could ensure the pin-chucks are a good tight fit (no slop), I think he said he aims for better than 0.002" tolerances. Any tighter and I wouldn't be able to slide the blank onto the rod because it's close to airtight.

For kit pens that I modify to closed-end (such as the cocobolo burl one) I used a regular pen mandrel which I sharpened on my grinder into a spade-bit. I'd double-drilled the barrel blank, first with the correct one for the pen kit, then a bit further with 7mm. After gluing in the kit brass tube, I slipped a slimline brass tube into the bottom hole. Then I put the regular kit bushing into the open end, and slid it all onto the mandrel. A couple of taps with a mallet secured it well enough to drive it (like a two-pronged spur drive). I kept the tailstock there until I was ready to do the final shaping on the closed end, that let me use heavier cuts without worrying about knocking it off the mandrel.

Both approaches have been successful for me -- no noticeable assymmetry in the wall thicknesses.

HTH

Reactions: Agree 1 | Informative 2 | Useful 1


----------



## Bean_counter (Aug 4, 2015)

Ok what's a fire piston???


----------



## duncsuss (Aug 4, 2015)

Bean_counter said:


> Ok what's a fire piston???



Google is your friend ... link


----------

