# Can i grind this tap



## slicksqueegie (Feb 9, 2011)

Can I grind this to make it a bottoming tap?

Do I use a 1" drill bit for the hole? 

This is to be used on wood.


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## Brink (Nov 22, 2010)

You can grind it into a bottoming tap. Just go slow, and keep quenching it to preserve the temper.

For metal tapping, I use a 29/32" drill. For wood, you can probably use a 7/8"


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## slicksqueegie (Feb 9, 2011)

Brink said:


> You can grind it into a bottoming tap. Just go slow, and keep quenching it to preserve the temper.
> 
> For metal tapping, I use a 29/32" drill. For wood, you can probably use a 7/8"


Thank you. Can I use a steal beam cutting blade on my miter saw to cut it? If so, should I cut it, then dress it with the grinder? After flattening, do I need to taper it? 
Thanks again.


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## Brink (Nov 22, 2010)

You can use an abrasive disc cutter on tool steel. Keep in mind those taps are super hard.

You could cut back and leave a little taper on the end and/or put a lead in chamfer on the hole to guide in the tap.


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## GeorgeC (Jul 30, 2008)

If you cut all of the bottom of the tap you will then find that it will be harder to start straight. You will probably be OK in wood, but it will never work in metal again.

George


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## BWSmith (Aug 24, 2010)

I would'nt cut it.......go get a bttm'ing tap.

You need to test the actual drill size on scrap.....different woods and grain structure will see slight but important differences when tapping wood.But,it does work VERY WELL for epoxied in inserts.I usually tap "dry".BW


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## woodnthings (Jan 24, 2009)

*This sounds dangerous!*



slicksqueegie said:


> Thank you. Can I use a steal beam cutting blade on my miter saw to cut it? If so, should I cut it, then dress it with the grinder? After flattening, do I need to taper it?
> Thanks again.


Unless the "fixture" to secure the tap is rock solid I wouldn't do it. I'd rather use a hand held die grinder with a cut off wheel and put the tap in a vise..... if you're gonna do it?

I guess I don't understand the reason for removing the taper, then as you suggested "retaper" it? Don't make sense to me. :blink:
You might want to grind off 1/2 the taper at most but that's all I would do, and I'm not sure of your application/reasoning. 
 bill


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## cabinetman (Jul 5, 2007)

A flat bottom tap has to be flat. It will need a very slight chamfer. Make sure the starting thread is very clean and sharp, as that can screw up all the threads cutting in.












 







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## Jr.Woodchuck (Nov 9, 2010)

You can grind, NOT CUT, the taper off of the tap. Done it many times in the die shop. If you have another tap use it to start the threads. Tap as far down as you can with the starter tap, then use you homemade bottoming tap. Tapering the bottom is not needed. You just need to remove (grind) the front of the thread off that is left after you grind the tap. Just as you would a screw you had cut off. Sometimes with wood. You can take a bolt, the harder the better and cut a groove down the threads to make a tap. You want the leading edge of the groove to be as sharp and square to the threads as possible. The same thing can be done with a nut to thread a dowel.


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