Reamer mod

[GlennW]

I need to enlarge a hole in aluminum from .250" to .281". Nothing that critical, just an oil passage. Sounds simple, but it's on a large part and the hole is drilled about 45° to the surface. It won't fit on the mill so targeting it with an end mill is not an option.

Idea---use a piloted chucking reamer to get the hole started in line and then finish with a standard chucking reamer, as the hole is only a couple of inches deep.

Set up the reamer in the Spindex and indicate it in. Holding it by the flutes was not my plan, but when I removed the new reamers from the tubes The gripping shank is .250" and the rest of the shank is reduced to about .200".

Set it up on the surface grinder and ground the pilot down to .250", then skewed the spindex a bit for a clearance angle, and tipped up the sine chuck for the lead angle, both angles arbitrary.

Grabbed a wheel that already had a beveled corner and ground the cutting edge.





Took it out of the Spindex and over to the lathe for a test run, and it actually cut freely on the first try!



Very quick and un-scientific, as I didn't even bother to dress the wheels, but it worked and will get the job done.

Now I better get my butt home before my wife figures out I snuck off to the shop....

[alphawolf45]

I dont consider a man has a complete home shop till he has a surface grinder..If mine broke down bad enough I couldnt repair it I would have another one within a couple weeks.Cant get by without it...I am always making reamers or counterbores for something.....Got to say though I dont have a fine pole magnetic chuck like that one you have....nice one..

[Harold_V]

Great idea and a very functional setup, Glenn. Well done!

Next time you face the same issue, you might consider using a twist drill instead of a more expensive reamer. Duplicate, in every way, the thing you did with the reamer. For a non-critical hole diameter, you'll be amazed at the outcome.

Keep your eyes open for a reasonably priced #2 Cincinnati tool and cutter grinder. In my estimation, they were the standard by which all other tool and cutter grinders were judged. They make a task like that a little easier.

Harold

[GlennW]

Hello Harold,

The twist drill did cross my mind.

I would need at least a 6" length drill, and was concerned about having only one cutting edge in the cut when starting as the hole is 45° to the surface. Seemed like it may be a bit clunky at the start.

I figured the multiple flutes of the reamer would run and feed a lot smoother as it's a hand drill operation.

Thanks!

Got to say though I dont have a fine pole magnetic chuck like that one you have....nice one..

I have a couple of other manual chucks that are not fine pole, and this one seems far superior. It's also electromagnetic, so it has a de-mag cycle as it releases, as well as other functions. It also has no residual magnetism when released so you can pick up the part as if it was lying on a wood table. I don't think I've used the other chucks or grinders since this one arrived.

I guess I'm spoiled for good now!

That's some really great stuff you are posting on the gun forum! I've been watching that with interest.

Thanks!

[GlennW]

Worked perfectly.