# What is this bit!?



## Czjon74 (11 mo ago)

I thought this was a countersink but, but it didn’t work out well. It seems like it has a changer on it but don’t really get it. I tired it in a drill. Is this a router bit?


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## DrRobert (Apr 27, 2015)

Doesn‘t look like a router bit to me, looks like a part to something,


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## woodnthings (Jan 24, 2009)

Those two photos don't look like their of the same bit, unless the lower one has a sliding collar to expose more of the small end?
The top one looks like a router round over bit. or possibly a laminate trimmer.
The lower one looks like a knob or handle or a gear.
Are they made of hardened steel, HSS?
Are there cutting edges?


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## yomanbill (Jul 7, 2020)

There are a variety of what are called "tamper proof screws". I have a few, but nothing like that. Could they be drivers for a couple of those? If so, perhaps the shoulders are there to stop the drive when the screw is flush. That's all I got. I'm reaching.


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## FrankC (Aug 24, 2012)

My guess they are for a cage system, common in aircraft industry:


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## Domo (Oct 10, 2021)

Top is a round over cutter for laminate to ease the 90° corners when a side meets the top - etc.
Bottom is a rabbiting bit.

Both of these will burn the edge if too much pressure is applied - this is due to the guide, which will spin and heat up - bits with ball bearing guides will give you better results with less burn out on inside corners.


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## John Smith_inFL (Jul 4, 2018)

I'm guessing they are for metal working: reamers to remove the burrs from the inside of tubing.
the one with the nib, will fit precisely into a specific size tube to ensure a square and burr free fit into the fitting.
Possible anything from automotive brake lines to aircraft fluid delivery systems.
they are not for woodworking.


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## Quickstep (Apr 10, 2012)

I think Domo’s got it. They are for easing the edge of laminates like Formica. I used to use bearingless bits yeas ago when building Formica countertops. We’d put a smear of Vaseline along the edge of the laminate to keep the bearing edge from burning the laminate. We did advance to bits with ball bearing guides, but discovered that the contact cement used on the laminate eventually gummed up the bearings to the point where they didn’t spin. We’d remove the bearings from the bits and leave them to soak overnight in lacquer thinner.


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## woodnthings (Jan 24, 2009)

woodnthings said:


> Those two photos don't look like their of the same bit, unless the lower one has a sliding collar to expose more of the small end?
> The top one looks like a router round over bit.* or possibly a laminate trimmer.*
> The lower one looks like a knob or handle or a gear.
> Are they made of hardened steel, HSS?
> Are there cutting edges?





Quickstep said:


> *I think Domo’s got it.* *They are for easing the edge of laminates like Formica.* I used to use bearingless bits yeas ago when building Formica countertops. We’d put a smear of Vaseline along the edge of the laminate to keep the bearing edge from burning the laminate. We did advance to bits with ball bearing guides, but discovered that the contact cement used on the laminate eventually gummed up the bearings to the point where they didn’t spin. We’d remove the bearings from the bits and leave them to soak overnight in lacquer thinner.


My post number 3 didn't "got it" ?

The other bit is still a mystery.


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