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Posted: 12/1/2015 12:40:10 PM EDT
I'd like to finish one of my kits soon, but am not sure what the correct method is of mounting the tube to my table, or how to go about cutting it?

The tube I'm cutting is 4130 with 0.049 W.

I have an array of HSS endmills.  I planned to rough cut it with a Dremil cut-off wheel and then do the finish work on the mill, but I'm still not sure how to mount the tube.  I've got a cheap HF mill vise, a decent adjustable angle vise, and a set of mounting step-blocks and clamps.  I know I have to set the mill to the lowest speed available, which I think is 300-500 rpm or so, and go slowly.

Any pointers?
Link Posted: 12/1/2015 7:48:52 PM EDT
[#1]
V blocks?   If you don't have any they're easy enough to make with amill and some blocks of 6061.  

What are you doing with the tube? What's the end game of the tube?
Link Posted: 12/1/2015 7:55:17 PM EDT
[#2]
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Quoted:
V blocks?   If you don't have any they're easy enough to make with amill and some blocks of 6061.  

What are you doing with the tube? What's the end game of the tube?
View Quote


Pretty much this.

How long is it?  What kind of features need to be milled in?  Got a drawing?
Link Posted: 12/2/2015 12:15:25 AM EDT
[#3]
It is a basic tube-gun SMG, turned striker-fired semi-auto.  It's roughly a 12" tube, roughly 1.5" OD and will need, on one side, an ejection port, and on the bottom, a sear hole and magazine hole.

I do not have a drawing, sorry.
Link Posted: 12/2/2015 12:38:20 AM EDT
[#4]
Link Posted: 12/2/2015 12:57:52 AM EDT
[#5]
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Quoted:
Standard V blocks will work so long as you mark up the receiver so you can adjust it in the V blocks for each cut.
http://www.micro-machine-shop.com/V-blocks_stepped_3.jpg


But more Precise with a indexer/rotary table with chuck and tail stock set up for a 4th axis for the rotation on the work piece  to set up next cuts instead.

View Quote


Those v-blocks look perfect for what I need.  Also, I've been looking for an excuse to get a rotary table, and now I may finally have one.
Link Posted: 12/2/2015 3:58:10 AM EDT
[#6]
You might consider machining some close fitting aluminum plugs to use as a backer under chuck jaws or a steady rest for the thin walled tube, especially if you have to cut threads on the ends.
Link Posted: 12/2/2015 8:25:25 AM EDT
[#7]
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Quoted:
You might consider machining some close fitting aluminum plugs to use as a backer under chuck jaws or a steady rest for the thin walled tube, especially if you have to cut threads on the ends.
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This!
Link Posted: 12/2/2015 5:22:26 PM EDT
[#8]
Link Posted: 12/2/2015 10:43:59 PM EDT
[#9]
Dani, where did you get the rotaries in your pic. I have an 8" one but need a smaller one for precise work/ smaller parts.
Link Posted: 12/4/2015 12:25:36 PM EDT
[#10]
Flll the tube with low temp metal of your choice, thread, melt out filler.
Link Posted: 12/4/2015 7:35:19 PM EDT
[#11]
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Quoted:
Flll the tube with low temp metal of your choice, thread, melt out filler.
View Quote

This - support for thin-wall machine operations is one of the core reasons that fixturing alloys exist.
Link Posted: 12/5/2015 3:30:21 AM EDT
[#12]
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Quoted:



This is the better choice, since its a PITA having to index round work by hand blindly instead (that triple checking and reset up makes what should be a easy job of rotating the piece a PITA instead.

As for rotory table, the tilting types work a lot better since at some point your going to have to tilt a work piece for rotatory work, but the problem is a good pre-buit one will cost you are arm in and leg instead.

Don't get me wrong, you can get away with the cheaper grizzly tilting base rotary tables, but getting them up to par to start with, is a project on it own to begin with.
http://i260.photobucket.com/albums/ii1/Tex-VA/RT-1-1.jpg
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Quoted:
Quoted:
Also, I've been looking for an excuse to get a rotary table, and now I may finally have one.



This is the better choice, since its a PITA having to index round work by hand blindly instead (that triple checking and reset up makes what should be a easy job of rotating the piece a PITA instead.

As for rotory table, the tilting types work a lot better since at some point your going to have to tilt a work piece for rotatory work, but the problem is a good pre-buit one will cost you are arm in and leg instead.

Don't get me wrong, you can get away with the cheaper grizzly tilting base rotary tables, but getting them up to par to start with, is a project on it own to begin with.
http://i260.photobucket.com/albums/ii1/Tex-VA/RT-1-1.jpg


Are you a guitar builder? What's that strat body doing there?
Link Posted: 12/5/2015 7:02:48 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:

This - support for thin-wall machine operations is one of the core reasons that fixturing alloys exist.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Flll the tube with low temp metal of your choice, thread, melt out filler.

This - support for thin-wall machine operations is one of the core reasons that fixturing alloys exist.


Cerrosafe is a higher priced metal aimed at gunsmiths.

The same alloy is available as a 'commodity' item for less money.
The dimensional characteristics are VERY well known.
Link Posted: 12/17/2015 12:05:18 AM EDT
[#14]
I've been eyeballing this kit for a while, but I can't find a 3-jaw (or 4, for that matter) chuck and adapter plate for it.  It's a Grizzly 6" kit.

http://www.amazon.com/gp/product/B0017IDWP4?psc=1&redirect=true&ref_=ox_sc_act_title_1&smid=A2LM8ZC59IT9RX


I'm pretty excited about this whole thing now.  I my girlfriend recently gave me a few other tools for my birthday that will come in handy for this project. (QCTP for lathe, boring bar set, mag base dial indicator)
Link Posted: 12/17/2015 11:32:57 AM EDT
[#15]
My setup, TIR less than 0.003.  A 4-jaw independent chuck allows more adjustment and clamping of odd shapes.
Phase II 6" Horiz/Vert Rotary Table http://www.phase2plus.com/details.asp?pr=PRECISION%20ROTARY%20TABLES&id=55



ENCO 6" 4-jaw independent chuck http://www.use-enco.com/CGI/INSRIT?PMAKA=271-6005&PMPXNO=952047&PARTPG=INLMK32
Everything will bolt right up with 3/8" cap bolts and t-slot nuts.  I use a 5mm hex, using the handle retaining bolt, in my cordless drill when I want power rotation.


 
 
Link Posted: 12/17/2015 3:47:57 PM EDT
[#16]
What is required to adapt those two together?

EDIT: I see now what you meant with the bolts and T-nuts.
Link Posted: 12/17/2015 4:20:53 PM EDT
[#17]
Link Posted: 12/17/2015 6:10:34 PM EDT
[#18]
(4) t-slot nuts http://www.zoro.com/te-co-t-nut-black-oxide-38-16-916-41406/i/G1777921/


(4) 3/8-16 x 2-3/4" Grade 8 cap bolts from your local supplier, I think I had to grind mine a little shorter as the nuts are "blind" tapped.





I tore the table down and cleaned it first thing.  For under $500 total it has worked very well for what I need.





I always indicate the part to the axis of the table, which is very easy with an independent 4-jaw, then use an edge finder and my DRO to center the table axis under the quill.





Get some brass and Alum. strips to use as pads for soft materials, like in my photo, the jaws WILL mar them otherwise.



Don't bother buying an import tailstock, make your own or modify an old lathe tailstock.



 
Link Posted: 12/18/2015 7:25:02 PM EDT
[#19]
No matter how you try and fixture thin metal deforms under cutting pressure.
Learn how to use low temp metal to fixture.

With hthe correct filler you c an thread metal half the thread thickness without a whole lot of stress (on you or the material).
Link Posted: 12/22/2015 12:30:42 AM EDT
[#20]
Thanks for all the info.  I ordered a phase 2 6" table.  I'm have yet to order the chuck. I'm still working on that.

I'd like a nicer milling vise next. Any input is appreciated.
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