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Hole Saw Mandrel

GregSY

Diamond
Joined
Jan 1, 2005
Location
Houston
I'm sure this has been done before....but I grew tired of hole saws wobbling and not doing a good job of cutting, especially at angles.

I took a small, free piece of scrap 2-1/2" round steel and cut one end to 3/4" dia and on the other end I made a small register of .578" which centers the hole saw. The 4 small holes are 1/4" on a 1" BC.

This mandrel - unlike the ones they sell for hole saws - does a great job of damping the usual chattering and keeps the hole saw running true. The hole saws still have about .030" of built-in runout, but that's tolerable in most cases.
 

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I don't think that Paragon would hold a candle to my scrap pile mandrel. It lacks the mass and (most important) the wide base that gives the hole saw stability. It's better than the Home Depot versions but still too small.
 
I apparently made a couple similar to the $8 ones (1/2-20 & 5/8-18). I made it out of 7/8 hex stock (all-head) so I could use the wrench for the hold downs. So far I haven't needed to use the wrench, shoving a big screwdriver through the holes in the hole saw and popping the handle with the base of my palm always breaks the threads loose.

If you face the threaded end of your hole saw you can get rid of a significant amount of your wobble. Obviously don't clamp on the saw teeth.
 

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The cost of carbide tipped annular cutters( up to 2" or so) is as cheap as premium hole saws and don't need any mods to work. Nothing wrong with modifing what you have to work as I often do myself. But since I don't do a lot of sheetmetal work most of my stuff is thicker sections and I hate hole saws especially since the cheap annular cutters came out. Found on E Bay Steel Dragon brand.
 
Here's an E-Bay one 100mm,carbide tip for 18.08,also a 3" for 29.00. Not as nice as the Steel Dragon. But should give a lot nicer cut than a hole saw. Can't get the link to copy. TCT brand. The Steel Dragon 2 3/8 is 70 or so. Worth looking into if you use them a lot. I bought a set(7 pieces) from Amazon up to 2" for less than 200 I think.
Also the Val-Cut tool does a nice job on large holes.
 








 
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