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Mitering tubes for tig welding

patrails

Plastic
Joined
May 7, 2013
Location
Pennsylvania
I haven't been on here for a while so I had to open a new account, couldn't remember my login

I just wanted to put this up to help some people out that may be looking for a easier way or a new idea. You will obviously see that I didn't invest a lot of time into it because I wasn't sure of the validity of my idea. . . .

My idea was to make a belt sander with inter-changeable drums to precision miter thin wall tubing (.028/.035/.7mm/.8mm etc) Instead I ended up making a attachment for my vertical mill. It took about a day to cobble this together and maybe $100 in materials.

When I turned the drums on the lathe I made provisions for a bearing to be installed at the end with a plan of using a piece to support the end and help the tool to take some load off of the mill spindle. However it works so effortlessly and I am using such a light belt tension that I don't think its that important (however I may still fab one because it really is the right way to do it)

I definitely need to make a support for the idler pulley side that I will have a micro adjust so that I can set belt tension and alignment in a more consistent and precise way.

After making this attachment I am surprised at how effortlessly it works, absolutely no chatter as compared to using hole saws or annular cutters that feel like they are fighting to get the job done. I wish I made this 5 years ago haha.

Anyway, maybe this is nothing new and you guys have been doing stuff like this for ever but I thought it might help some people looking for a better way . . .. tube mitering on a vertical mill - YouTube
 
Really? So I guess you have never mitered thin wall tubing.

I guess I remember why I haven't been on here in so long.


Real shitty attitude a$$hole
 
Thanks for sharing. Some real creativity here.
Micro adjust for the opposite side good idea.
Oscillating movement to even belt wear would be good. How about a drum with no idler pully? Like the drum sanders.
V-blocks and different size drums & you could do various sizes on the same setup.
If you reverse the setup so the sander was to the right and vise left would the sparks go away from the operator?
Add a spark shield so you don't "f..up" your mill.
 
Thanks for sharing. Some real creativity here.
Micro adjust for the opposite side good idea.
Oscillating movement to even belt wear would be good. How about a drum with no idler pully? Like the drum sanders.
V-blocks and different size drums & you could do various sizes on the same setup.
If you reverse the setup so the sander was to the right and vise left would the sparks go away from the operator?
Add a spark shield so you don't "f..up" your mill.

The blocks I made have a sleeve in them to fit different size tubes and to orient the tubes so its easy to have a miter at 90 degrees in relation to one another where v blocks would make this more difficult.

The reason I did a belt instead of drums is for wear but also to have infinite size adjustment with turning different size drums.

The spark situation is valid but really not as bad as it looks haha.
 
Always thought I would buy a Linder's Coper. Nah, not for over 3 grand. Using an endmill on heavy wall is slow, but works good, if you've got the right sized e-mill. But on thin wall, it's usually the last little bit to go and whammo! Other than the abrasive factor, I like your idea. Maybe fab up some shields.
 
Clever. I may do something similar. Ignore the overly corrosive wording of some posts.

A constructive note is that you will blow abrasive bits around on your mill, so containing the abrasive dust to keep it out of the ways, etc. will be worth your while.

How much head room to you have for more angle? (Uh, say, the downtube of conventional bicycle....)
 
Looks cool... But I wouldn't want that shit anywhere near my mill. Sorry if that means I have a shit attitude too, I would just cringe for my ways. I have mitered tubes the same way on a Burr King, works like a dream.
 
Good ingenuity and fabrication but the abrasive dust would be a real concern for me unless I had a beater of a BP and was going to dedicate it to notching..............Bob
 
In my "Notching days" (Aviation seating) We found that using the mill for shaping the fishmouth was often complicated when the tubes met at steep angles. Also, working around the milling machine became difficult when fitting "Bends" of any size. "What to do with the material sticking out?"

We ended up most satisfied with unguarded grind wheels on pedistals with an eight or ten inch wheel dressed to the correct radius. (most of the work was fitting 1 inch to .75 inch O.D. with a variety of wall thicknesses)

Template forms were generated with one of the layout software tools,* printed on mylar, with a registration mark for radial position. The template was cut and then wrapped around the tubing. A "silver" pencil left a readily visible curve to grind to. The shaping operation of any repeat work might have taken 4 minutes tops per end. One off work took a bit more to learn the position best suited to achieve the required fish mouth. Beveling/deburring the outside prior to welding took at least as long, with the same radiused wheels serving for that task as well.

A means to an end, with as many ways as there are men!

* like this, but 35 years ago ;-)
Tube Coping Calculator
 
The concern of the abrasives are valid but really rather simple. You just move the head forward on the machine so the bed covers the ways, then lay a towel or rag over the exposed ways in the back. I always try to think through my operation before I start "ounce of prevention pound of cure" and all that.

I like the quote above. . ."A means to an end, with as many ways as there are men!"
 
Clever. I may do something similar. Ignore the overly corrosive wording of some posts.

A constructive note is that you will blow abrasive bits around on your mill, so containing the abrasive dust to keep it out of the ways, etc. will be worth your while.

How much head room to you have for more angle? (Uh, say, the downtube of conventional bicycle....)

Shouldn't be a problem at all. I have built some trail frames with a 1.75 pierced down tube using a annular cutter and that would get real tight if I was building a frame around a fork with taller axle to crown measurement. But the annular cutters have a short shank and with the 4" wide belt the work is far from the quill.

The frame I am building now is based on a fork I modded to 35mm of travel so the A. to C. is only 17" and I will have +.25 at the bottom bracket so the d.t. to h.t. angle is not very tight. When I am complete this one I will be building a more conventional xc frame so time will tell haha
 
I like the clamp blocks , what's the story on those ? Did you fab or buy them ? How do they grip or lock the tube ?

Made those a while ago. 4" block I bored a 2" hole on the lathe (thats the largest tube I usually work with) I turned delrin shims for all the different sized tubes I work with. I also used a 1/2" ball endmill to machine the reliefs so in theory the block will flex equally to apply even pressure to the tube. The delrin seems to grip really well with minimal pressure (2 pinch bolts but don't need to be tightened much).

I have another little project I need to get to and that is casting some 2 part urethane inserts for clamping tubes I use sometimes that are shaped pear on one end penta on the other. Maybe next week, so much to build and so little time haha
 
For thin wall tubing, you can do that on a belt sander by hand. For a 90, just a 45 on one side, and then a 45 on the other, then just round over the ends.

Abrasive dust on a machine tool isn't a good idea.
 
Horizontal mill is the ticket instead of the glorified drill press that is a Bridgeport. It is far less likely to grab and you just mount a swivel vise to do your angles. Fishmouthed zillions of tubes of all sizes and wall thicknesses on a little Van Norman 6 at the airplane museum.
 
Nice setup!,
I do wonder about all the tiny metals and sanding belt particles being sent all over your mill getting into ways and spindle perhaps?

i'm very new to having a mill, but I fight the small metal shavings from the end mill constantly, just something that crossed my mind (which I now see has been posted) still like your setup!
 








 
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