how do i turn this?

[ramjack]

Hi,

I need to turn a 6061-T6 aluminum illustrated above and I need some advice on how i should go about accomplishing that. What shape should my boring bar be? The inside depth is about 16 mm. and the inside wall will be threaded. The little nipple inside is a critical part. it is about 2-4 mm in diameter and its height is about 4 mm. Any advice will be appreciated. Thanks.

[rhino]

you could probably try a trepanning/face grooving tool to do the inside. you would have to face the spigot back after reaching the desired diameter. A question though: how do you measure the spigot if its a crucial size? if its so crucial i dont see you can measure it with a vernier! maybe if you can help us out in what it will be used for maybe we can tell you how crucial it has to be.

[phantomcow2]

Easiest thing would be to use a milling machine with a rotary table.
If not, you should be able to plunge a little bit with a boring bar, since you cant drill a hole past the height of the nipple. Use a regular boring bar to get the larger inside dimension, make plenty of room, you cant turn the 4mm nipple because of the tools shape. Use a left hand turning tool (which if held side by side, will be opposite cutting shape of the boring bar) to turn the 4mm section. The carriage movement can be measured using a dial indicator, and the cross feed you may not need it since the leadscrew is metric anyways.

[ramjack]

hi guys, thanks for the reply.

Rhino: this is for a paintball marker. it is where you screw in the co2 tank. the nipple is there to push open the co2 tank valve or something (not exactly sure what they call it). The nipple may be smaller than the measurements i gave initially.

I was thinking if turning is will be too complicated for me, i may do it in two piece. I will just add the nipple like an insert or something.

[ramjack]

hi guys, thanks for the reply.

This is for a paintball marker. it is where you screw in the co2 tank. the nipple is there to push open the co2 tank valve or something (not exactly sure what they call it). The nipple may be smaller than the measurements i gave initially. This is a rough study so far.

I was thinking if turning this will be too complicated for my skill, i may do it in two piece. I will just add the nipple like an insert or something later..

[Runner4404spd]

thats exactly how most of these parts are made. make a 2 peice assembly or injection mold it in plastic. if you need aluminum you can cast it with decent results. if that nub is what is releasing the check valve on the cylinder than it doesn't ahve to be that precise.

[tim-tbl]

I would drill then bore out to the the top of the noggin and then get a parting tool and scoop out enough matl so yo can get a boring bar in however you will need a left hand and right hand boring tool.

[Mcgyver]

I think you found your own answer. might be that its better with a steel pin anyway, from a durability point of view. my first reaction was does it have to be as shown, ie if its really a head scratcher on how to machine it, maybe the design needs revisiting - but you figured that out yourself.

if would not be 'hard' to machine it and measure it, just a big pita. I say not hard because I'm sure its within your abilities (what ever we do on the machines inevitably is just a series of little steps, the grey-matter, fun and experience is in figuring out the steps) its just a lot of unnecessary effort and time vs a design change; need to grind a couple of special tools, etc....but its usually better if you can design your way out of the tricky ones.

[ramjack]

well, i tried turning it in one piece just to know if i can make it and i think did ok. just took me a lot of time grinding some tools.

[ISO Coder]

Instead of trying to turn that nipple make a threaded hole (M3 or similar) in its place and make a steel pin that you secure with some Loctite.

And as i recall from my Paintball days (12 years ago) that pins dia. is 4mm

[ramjack]

Yes I might just go and take that direction and use a steel pin insert.it seem much less process than turning it in one piece. thanks.

[ramjack]

Originally Posted by ISO Coder Instead of trying to turn that nipple make a threaded hole (M3 or similar) in its place and make a steel pin that you secure with some Loctite. And as i recall from my Paintball days (12 years ago) that pins dia. is 4mm

by the the, would you also know the exact thread specs for the co2 tank valve?