Boring A Large Hole?

[jocat54]

I am in the planing stage of make a quill stop plate for my mill. My question is how can I bore a 3.535 hole in 5/8 aluminum plate? My 2 " boring head screws on to a r8 arbor and all my boring bars (cheapy) have the cutting edge in the wrong place when mounted horizontal in the boring head. I can't run the mill in reverse or it would unscrew the arbor from the boring head. Hope I made some sense out of that.
I hope I am missing something really simple.
I am actually planning on cutting the bulk out with bandsaw and then clean up the hole to size by boring.

 

[Tony Wells]

You just need a bigger boring head. You're welcome to come borrow one, being you're close.

Or, with a boring bar in the old fashion sense, with a tool steel clamped in it, use the vertical holes but hang the tool steel out further. As long as that doesn't give you chatter problems, it should work out. And I assume you can't get this set up in the lathe?

 

[mikey]

You could just buy a boring bar for this purpose. Check Mesa tools: http://www.mesatool.com/products/boring-head-attachments/

See the bottom of the page on the right - 1/2" cross hole bar - $30.00.

 

[Wreck™Wreck]

Does the boring head not have an radial hole for mounting tools? As seen here http://www.wttool.com/index/page/pr...?(Criterion)&gclid=CKCRoLOwydACFdgYgQodsEoI5w

Clamp a tool through the transverse hole and bore away.

Good Luck

 

[jocat54]

Tony, Thank you for the offer.
I think I will just make me a boring bar from some inserts I have with the cutting edge in the right place.

 

[fleckner's garage]

I attempted this with success. was opening up a bore on a wheel spacer. i took light cuts and never had the head unthread on me. Certainly not the best way to do it, but it did work.

 

[jocat54]

To update this-- I just clamped a lh lathe tool (1/4" cheap carbide insert) horizontal in the boring head and it worked great.

 

[kwoodhands]

I am in the planing stage of make a quill stop plate for my mill. My question is how can I bore a 3.535 hole in 5/8 aluminum plate? My 2 " boring head screws on to a r8 arbor and all my boring bars (cheapy) have the cutting edge in the wrong place when mounted horizontal in the boring head. I can't run the mill in reverse or it would unscrew the arbor from the boring head. Hope I made some sense out of that.
I hope I am missing something really simple.
I am actually planning on cutting the bulk out with bandsaw and then clean up the hole to size by boring.

Do you have a lathe? If so you can do this several different ways. One way is to part the circle off, called Trepanning.
Another is to mount the work in a chuck with the center established and first bore with large holesaw. Then using a boring bar to finish to size. I would Trepan the hole myself. Drill a center point with a spotting drill or a center drill.
Mount the work on a face plate with shims so the parting tool does not cut into the face plate. You can clamp the work on the outer edges of the work making sure the cutter will not hit the clamps. Install parting tool in the tool post. Cut at the perimeter all the way thru. If the parting tool binds the widen the cut a bit. When you are thru you will have a useable piece of aluminum for another project. I forgot to mention an old timers trick to get the work to center quickly. Before you clamp the work ,move the tail stock up with a live or dead center til the point is in the hole on the work. Lock the tail stock and push the quill forward til the work is tight to the shims between the face plate. Now you clamp the work and remove the tail stock and center.

mike