Need advice on boring head project.

Sandia

Sandia

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Problem: I need to open up a bore from rought 1" to 1.125 using my mill and a boring head. I have two boring heads, one is 1/2" and the other is 3/4". I also have a 5/8" boring bar I will have to use because it is long enough.

Now then, I was thinking of making a temporary bushing out of 6061 to adapt the 5/8" bar to fit the 3/4" boring head. I will need to drill then bore the bushing as I don't have a 5/8" reamer. Simple enought but the kicker is the bushing will have to have a 3/8" hole (appx.) drilled thru the side of the bushing so the grub screw that tightens on the boring bar will line up. Hope that makes sense.

The question is how would you drill this hole in the side without distorting the bushing as it is a very tight fit. I know you can buy the adapters, but they are horrible expensive, especially for a one time operation.

I have a 3/4 Aloris boring bar but it is too long and I don't want to shorten it.

Sorry for the long post. Any suggestions will be appreciated.

Thanks, Bob
 
Drill the grub screw hole before you bore the bushing.

Don't apologize for a long post, the more information you can give us, the better we can understand the problem.
 
Thanks Jim, that is what I figured. I would rather use the 3/4" boring bar but I don't want to shorten it. Will try your suggestion.
Thanks
 
If it was just some thin wall you could use some wood dowel or some alum. Make it a little smaller then the hole and use shims under it for a good tight fit. That way it's easy to remove
 
What if you make your bushing and just slit one vertical side off to produce a 3/8" wide slot the whole length of the bushing? That way you don't have to locate a hole.
 
Why are you using aluminum for a bushing? I advise only using steel. Aluminum is a slippery metal,and so is brass. You don't want your boring bar to rotate under the pressure of cutting.
 
george wilson said:
Why are you using aluminum for a bushing? I advise only using steel. Aluminum is a slippery metal,and so is brass. You don't want your boring bar to rotate under the pressure of cutting.
Click to expand...

Thanks George,
I considered that issue and may remake the bushing from metal to be safe. Although the boring bar has a flat on one side for the grub screw to face up against to prevent that and it is for a one time operation.

Bob
 
I thought aluminum would gall and prevent slipping? As for trying to put a hole in that thin wall sleeve. I would just put it in a vise holding it by its ends and maybe support it with a “V” block underneath. I do not see the need nor take the extra time to make a plug that fits the sleeve all to prevent distortion. Or hold the sleeve in a collet (if you have that capability) and make the hole that way…Good Luck, Dave.
 
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