School is in session

[Tubby]

Back spot face cutters. I used them quite often especially in the air craft industry when a counter bore was needed on a flange that had no clearance to counter bore in a conventional manner. I even helped built a couple dedicated machines for that purpose.

 

[brino]

Those are the reason why I added a reverse switch to my drill press motor.
I got a large, new, but old set for cheap from my local tool place.

I have used them to make counter-bores for the heads of socket-head cap screws.
I use the pilot to line them up with the thru-hole for the bolt, then clamp the work to the table.
I run them very low speed.

Although I'd rather do that kind of work in the mill, I wasn't sure that nothing in the mill drive train would loosen if run in reverse.

Brian

 

[bug_hunter]

I have used them to make counter-bores for the heads of socket-head cap screws.
I use the pilot to line them up with the thru-hole for the bolt, then clamp the work to the table.
I run them very low speed.

Any benefit over a counter-bore bit? When using your drill press, do you attach the cutter beneath the drill press table, and bore from below, or do you chuck the cutter/mandrel in the drill press backwards?

Not sure I'll ever figure a handy way to use them, but one snowy day, something might click.

 

[RandyM]

This may help.

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www.mcmaster.com

 

[Jake M]

Any benefit over a counter-bore bit?

Yes, but only in certain situations.

When using your drill press, do you attach the cutter beneath the drill press table, and bore from below, or do you chuck the cutter/mandrel in the drill press backwards?

They would be used to spot face/counter sink the BOTTOM of the work piece if it were in a drill press. They cut while you're pushing UP on the quill. You'd get the pilot/shank in the chuck, lined up, and passed through the hole, and then attach the cutter from underneath the work. You would have to remove the cutter before removing the pilot/shank from the hole.

Not sure I'll ever figure a handy way to use them, but one snowy day, something might click.

They are basically a solution to a problem that does not happen every day for most work. When you have a workpiece that does not allow access to a drilled hole from both sides, this is how you might spot face a seat or countersink for a bolt when you can't get a drill or mill to that side of the project.

 

[brino]

Any benefit over a counter-bore bit?

Nope except I got a full set for cheap, so I have a range of sizes.
I do NOT have a full range of sizes of regular, right-hand cutting counter-bores.

When using your drill press, do you attach the cutter beneath the drill press table, and bore from below, or do you chuck the cutter/mandrel in the drill press backwards?

As I said above, I added a rocker switch to the drill press motor to select forward or reverse.
I added that option explicitly because I had this drawer full of cutters.
I select direction BEFORE turning on the drill press motor in the usual way.
It cannot be switched for instant reverse for tapping, etc.

Since I run the drill-press in reverse I can work on top of the table.

Brian