Back spot facing

[ckwhite]

We have a part with 6 counterbore and clearanced holes for 1/4-20. the way that we hold the part we can't put the counterbores in. We have to later setup on a bridgeport to do these counterbores.

 

I have been told that there tools available that I could drop into the clearance holes. Turn on the spindle and the cutting edge of the tool will pop out, allowing me to do the counterbore.

 

Does anybody have experience with this type of tooling? Who might carry these?? MSC? Kenneametal?

 

Thanks for the help

[ckwhite]

I guess they are called reverse spotfacers? maybe?

[Jaz]

I have used what you describe but not in that small of a hole. The ones we have are Parlec brand.

[rob@fain]

Try this

[MultiAxGod]

We used to make our own and called them flip out back spotfacers. I would agree with Jaz, that's a pretty small hole to do this with and if your material is hard, it seems like it would brek the joint off.

Remember to reverse your spindle when cutting and then reverse it back to retract or ......oooops

[ckwhite]

The material is 6061 aluminum. I'll check out any brands that you guys can come up with. One that I called yesterday won't do a hole that small. So I may be SOL.

[SydwazShawn]

I use one made by Parlec. It works really well on alum. They usually give you extra bits when you order one. The one I have is a .330 shank. It works with a spinning weight that flips the tool out by turning the spindle CW or CCW. I would recommend them, and have had no problems. The only thing is that they are expensive, so make sure you have a lot of holes to justify it.

[Zoober]

Steiner goes down to .248 dia pilot hole, with a .435 cbore max for that pilot.

We love them... use them in Ti, Alum., 4140...

web page