Who's a machinist?

snakeskinner

Twelve Pointer
I am working on a DIY project that requires me to drill and tap a hole in the end of a solid round 6061 aluminum bar 9/16 OD. What would be the best thread maybe 1/4-20 or 1/4-28? The bar will be about 3" long. If I drill and tap at least an inch I'm guessing that would be better than going shorter. Anybody in the Raleigh/Durham area have a lathe that can help a guy out?
 

nccatfisher

Old Mossy Horns
Contributor
Aluminum isn't the greatest at holding threads, what exactly are you holding? If you were closer or get up around Lexington I am retired and have a lathe and would be glad to do it. You are talking about a few minute job.
 

snakeskinner

Twelve Pointer
The bottom device in the pic is a camera arm where the silver protrusion fits into a plastic bushing receiver/base mounted to a tree. The one above it uses a different mounting method and I want to adapt it to work in the same receiver/base. I want to cut this rod to length and drill and tap it and then affix it to the bottom of the square tubing so that it can be used in the same receiver/base.IMG_7304.jpg
 

Wildlifer

Twelve Pointer
Just a thought but could you use a 9/16 diameter bolt, cut the head off to use in the mounting portion then use the threads with 2 nuts to attach it to the square tube?
 

JoeR

Six Pointer
I'm in Stokesdale, so not terribly far from Raleigh, and have a lathe. If you get desperate enough to make a trip out here, let me know. You're welcome to drop by.
Joe
 

snakeskinner

Twelve Pointer
Just a thought but could you use a 9/16 diameter bolt, cut the head off to use in the mounting portion then use the threads with 2 nuts to attach it to the square tube?
Yes but would have to drill 9/16 hole in square tubing and that wouldn't leave much left. I also want to include a large washer between said rod and the square tubing to act as a shoulder.
 

Hoss

Six Pointer
Thirty five years ,four in a job shop last thirty one in a manufacturing plant still going. Sorry no machinery at home.
 

bigten

Old Mossy Horns
Contributor
Relatively simple project. Either thread pitch will work for what you want to accomplish. I'm sure someone near you will help out. I'm just too far away to make it worthwhile..
 

bwfarms

Ten Pointer
Use a forming tap instead of a cutting tap.

How much are you trying to shave off the rod? If not much, chuck it in a drill and spin in some sandpaper.
 

nccatfisher

Old Mossy Horns
Contributor
I see what you are wanting to do. 1/4" will be fine. Sorry I am too far, it would be an easy fix. Since you aren't under any real constraints as far as depth on tapping it you could use a gun tap in 20 or 28 TPI they are easy to start and will tap that aluminum easily. For what you are doing if you started center or real close to it it could be accomplished in a drill press.
 

brownisdown

Twelve Pointer
Contributor
Why not mail the rod with prepaid envelope to one of the guys offering to help with a few dead presidents in it for their troubles?

Sent from my SM-G955U using Tapatalk
 

Eric Revo

Old Mossy Horns
Contributor
Drill a pilot hole and then run a self tapping bolt with a nut run all the way to the top of the bolthead. When you get it to the depth you want, cut the head of the bolt off with a dremel and run the nut back and forth a couple of times to clean the threads and you're done.
 

Mr.Gadget

Old Mossy Horns
If it is like it sounds the 1/4 screw will hold all the weight of the arm. It will not work long, it will fail. First time you really load it it will give way.

If you go that way using the 1/4 inch to hold it, drill the bottom out if the tube so the pin sticks into tye tube abd then only drill 1/4 inch hole in the top to locate and hold in place. The shear and bending force will be less.

Or go with a smaller bolt like 3/8 inch and make a sleeve for the bottom from aluminum tube, brass or pvc.

As it sounds you are wanting to do, drill a 1/4 hole top and bottom then run the 1/4 bolt through the tube into your pin.
The tube will crush with no inside support if it is tube and not bar.

If you need somones help in the first place why not just have that person weld the two parts up? Would be easy to find a welder.
 

snakeskinner

Twelve Pointer
Yes I have considered crushing the square tube and planned to make a bushing to go inside it to prevent collapse. This will also give it some strength.
 

snakeskinner

Twelve Pointer
Since I had plenty of aluminum rod I went for it. I drilled a single hole in the square tubing and despite the care I took to make it centered, it is slightly off center. I should have drilled a pilot hole. I then drilled into the aluminum rod and used a self tapping bolt to secure it. I got it fairly straight even though I freehanded it with a hand drill. Bottom pic is the result.IMG_7322.JPG
IMG_7326.JPG
 
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