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Sharpening a spade bit

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Forum topic by coloradoclimber posted 12-28-2009 06:53 AM 7006 views 0 times favorited 7 replies Add to Favorites Watch
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coloradoclimber

548 posts in 3532 days


12-28-2009 06:53 AM

I saw Jim’s post questioning how to sharpen a Forstner bit and not wanting to hijack his thread I’ll start a new topic.

I’m wiring up a new basement and needed to drill lots of 1/2, 9/16, and 5/8 holes in the studs and headers to pull romex through. So I pull out my big box set of spade bits, you know the ones, cheap for a full set, soft steel, start dull and stay dull til you throw them away. I’m happily, or rather unhappily, drilling away and thinking man, could these bits be any duller.

So I decided enough is enough, I pulled out an 8 inch mill file and took to it. I wont go into how to sharpen a spade bit, it’s pretty obvious. I held the bit against a stud to steady it and gave it a few strokes into the bevel, then ran the bit face flat on the file a few strokes, and wow what a difference. I mean duh, but I’ve never really thought of sharpening a spade bit before, use ‘em, abuse ‘em, throw ‘em away.

Anyhow once I got a sharp bit I was addicted. The cut was so much faster and cleaner, and easier on the drill. Problem was the soft steel of the bits dulled out again in half a dozen cuts or so. And once I’d starting drilling with a sharp bit I couldn’t stand using it dull. I was popping it out every 8-10 holes and giving the edge another lick. Fortunately it is fast and easy to re-touch the edge and I didn’t worry much about the cutting angle or maintaining the same angle, cheap bits and all.

Anyhow, if you use spade bits and you’ve never thought to touch up the edge it is fast and simple and really makes a difference.


7 replies so far

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scrappy

3506 posts in 2895 days


#1 posted 12-28-2009 09:26 AM

Been there Done that. I thought everyone was sharpening their spade bits? You have to sharpen twist drill bits don’t you? I have been doing this for years and never thought to mention it. Sorry guys.

One other thing I did was to modify the tip on the bit I use for tea lights. Took off most of the point and recentered and sharpened it. Now it is only 1/4 inch longer then the spade part. Makes for a better hole. (of course, now the wife got me a set of forstner bits for christmass and I don’t use it)haha

Thanks for shareing the info.

Scrappy

-- Scrap Wood's the best...the projects are smaller, and so is the mess!

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TopamaxSurvivor

17671 posts in 3140 days


#2 posted 12-28-2009 09:44 AM

You need an auger with a self feeding screw point if you are going to play electrician.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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coloradoclimber

548 posts in 3532 days


#3 posted 12-28-2009 07:55 PM

Topamax, yeah, you’re probably right. I remember the old brace and bits my dad had. Even as a kid I could drill a 3/4 inch hole through a 4×4 by hand.

BUT, the nice thing about using cheap junkie spade bits is that if you hit a nail drilling a header or going through stacked studs, no worry, just wiggle the bit to try to get around the nail. If that don’t work, just move over and stab again. No tears shed for running a good tool into a nail.

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TopamaxSurvivor

17671 posts in 3140 days


#4 posted 12-28-2009 09:29 PM

A good sharp auger will cut nails off or pull them out if they get around the screw point. You want to use a ship auger type without the flutes sticking below the end.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

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TopamaxSurvivor

17671 posts in 3140 days


#5 posted 12-28-2009 09:31 PM

You need to use a good 1/2 drill like a Hole Hog to to do that sort of work.

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View PurpLev's profile

PurpLev

8523 posts in 3113 days


#6 posted 12-28-2009 10:02 PM

I only used self driving auger bits for running wires… much faster, makes larger holes. takes more abuse.

but to the OP- sharpening spades is great, these are probably the easiest bits to sharpen.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View LONGHAIR's profile

LONGHAIR

94 posts in 3279 days


#7 posted 12-29-2009 12:05 AM

I do them with a small diamond wheel that I spin on my drill press. It works very well…and if you cut toward the cutting edge, you get a small burr like a scraper has. This make the bit more aggressive and it seems to last longer that way too.

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