How To Hold??

[Ronno6]

How would I go about chucking this critter up in my lathe in order to turn the stem diameter down a bit???

[Ronfiveo]

How would I go about chucking this critter up in my lathe in order to turn the stem diameter down a bit???

I would use a "chuck center" and a " live center" in the tail stock.

Ron

[sb327]

Entire length of stem?

How does stem attach to brass? Press fit?

Dave

[Ronno6]

Entire length of stem?

How does stem attach to brass? Press fit?

Dave

The entire length would be preferred, although the stem will need to be shortened about 1/8"
I don't think 1/8" is enough to hang on to.....
The 1/4" just behind the poppet could remain original.

Dunno how it is attached, but the poly seal obscures the joint.

Maybe I could make a bushing, the major ID to allow the poppet to enter, with a closed end, and put a hole thru that end the size of the stem.
Then tap the open side for a set screw.
I could insert the stem thru the hole and secure with a set screw from the back side........

[OTmachine]

Seems like the bushing would work if your collet runs true.  I would use soft jaws bored to fit and concentric with allowance for the brass end.  Machine 1/2, flip, and do the other half using HSS tool to cut.  My .02

[sb327]

If the stem can be shortened by 1/8”, that would be enough to center drill the stem and use a center. You might have to hold the brass in a chuck and the stem in a steady while center drilling.

The bushing plan seems like a good plan as well.

Dave

[avator]

Just a note..
The brass does not make the seal so putting small scratches in it to secure it in a chuck for the work should not affect it's function.

[Ronfiveo]

I should have said, dead center in the chuck and a live center in the tail stock.
It's not like you're hogging off .125" at a time. That way the O. D. will be concentric with the I. D. .

Ron

[pan60]

how much do you need to remove?

i dont see how centers would work wothout a dawg and if its dawged you might as well use a collet grab the .125" your scrapping and suport the the brass.

not that i would know anything about machining ; /

[Ronfiveo]

how much do you need to remove?

i dont see how centers would work wothout a dawg and if its dawged you might as well use a collet grab the .125" your scrapping and suport the the brass.

not that i would know anything about machining ; /

You add pressure from the tail stock, pinching it between the two centers, enough to hold it and it not slip.
I've done similar in the past taking off .010" at a time until desired O.D. is reached.
No marks any where.

Ron

[pan60]

how much do you need to remove?

i dont see how centers would work wothout a dawg and if its dawged you might as well use a collet grab the .125" your scrapping and suport the the brass.

not that i would know anything about machining ; /

You add pressure from the tail stock, pinching it between the two centers, enough to hold it and it not slip.
I've done similar in the past taking off .010" at a time until desired O.D. is reached.
No marks any where.

Ron

i cant see that as an effective method and yet you still lack zeroed centers to offer a precised cut?
you might get lucky if you spent enough time tapping it around then grinding it?
wich persanally i would grind it regardless to get a finish i wanted.
before i tried it like that ( between centers ) i would just knock out a new one most likely the easiest and fast.

[Ronno6]

how much do you need to remove?

i dont see how centers would work wothout a dawg and if its dawged you might as well use a collet grab the .125" your scrapping and suport the the brass.

not that i would know anything about machining ; /

The Benji stem .a .155" ; the Daist is .122"so looks like .033 or .0165 depth of cut....

[eeler1]

As Pan mentioned, collets would be an option for the headstock end, if you can find the size to fit, 3/32" for the Benji.  Snug the brass up to the collet, then drill a shallow center divet on the brass end so you can use a live center there.  Then extend it to hold the 1/8" of the stem in the collet, live center the other end.  That would probably work.

Aren't these hardened?  Maybe go slow and use a carbide tool.

[OTmachine]

I forgot to mention that when I said HSS, I meant Mo-Max or Super Mo-Max.  Carbide pushes too much.

[Ronno6]

This is probably a 1-of situation, so not worth investing in tooling.

I think opening up the stem hole in the valve id a more viable solution.

If that doesn't work I will replace with a Daisy 853 valve and move on......

Thanks for the guidance, y'all!

[pan60]

This is probably a 1-of situation, so not worth investing in tooling.

I think opening up the stem hole in the valve id a more viable solution.

If that doesn't work I will replace with a Daisy 853 valve and move on......

Thanks for the guidance, y'all!

if you have a nice reamer that would be ideal.

[Ronno6]

This is probably a 1-of situation, so not worth investing in tooling.

I think opening up the stem hole in the valve id a more viable solution.

If that doesn't work I will replace with a Daisy 853 valve and move on......

Thanks for the guidance, y'all!

if you have a nice reamer that would be ideal.

I do not.......