Can u sharpen hole saws??? spade bits
m2akita
| Posted in Tools for Home Building on
Soooooo………..someone thought they could cut through some cinder block with my 2-1/8″ hole saw. In case any one is wondering……YOU CANT ( at least not with mine). thump! thump! thump! (thats me hitting my head on the desk, again!).
Does any one know if you can resharpen the teeth on a hole saw, and if so, whats the best technique?? And while where on it, how about sharpening spade bits. I know Ive seen something somwhere on how to do it, but I dont feel like going and looking for it right now.
Thanks for any help.
-m2akita
p.s. the sooner the response the better, Im supposed to put in 3 doors on Monday. Might be easiest to just go buy another hole saw. Thanks again for any help.
Replies
If you have the right equipment (files, tooth setter) for sharpening hand saws, I can't see why you couldn't also use them on a (non-carbide) hole saw. But after trying to use a saw for cinder block, it's probably not worth the effort.
As for the spade bits, I sharpend them all the time -- with a small file. Takes about a minute.
"I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
I do the spades on a gring wheel, less than a minute each.
Might not be perfect, but then, a spade bit is not exactly a precision instrument.
Once in a while the elec. or plumber will get there hand on a spade bit of mine chucked in a 3/8 VSR.
One try and they're cursing the Hole Hawg in a second. Like shooting a stud with a laser beam I tell ya!
EricI Love A Hand That Meets My Own,
With A Hold That Causes Some Sensation.
[email protected]
Yeah, thats pretty much what I was thinking. That its probably not worth the effort to try and sharpen the hole saw. Plus, I dont have a tooth setter or anything for doing handsaws ( whats a handsaw ??? :} ).
Can you describe to me how you sharpen your spade bits. I should quite being lazy and go and try and find that article I saw on sharpening them ( i need pictures).
thanks,
m2akita
I will ask the guy who does our sharpening, but I think they can do anything.
Sorry, no pics -- I don't know how to post pics, and besides I don't even have a digital camera. But sharpening the spade bits is really easy. If they don't have the points (on the permeter of the bit), you can just touch them on a grinder -- making an effort to keep the same angle on the cutting edge as the original.If the bit does have the points, I use a small file with a point (I think it is called a ships auger file), and file away -- again maintaining the same angle they used for the cutting edge.If you grind off the perimeter points, then you can use any mill file to touch up the cutting edge. I find this easier and faster than trying to use a grinder. I use a vise to hold the bit.The steel used for spade bits is really soft -- so it sharpens easily (but also dulls quickly)."I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
Matt, still have my number? If the hole saw's only dull, we can fix it in a couple of minutes. Bring out the spade bits and I'll show you how easy it is on a grinder.
I still use a handsaw and, other than the Japanese ones, sharpen regularly. It really isn't complicated.
Headed back up to my copper roof now but I can pause whenever if you want to come out.PAHS Designer/Builder- Bury it!
Is the hole saw a real high end one, or just a $20 one from the hardware store?
I'm wondering if it's worth trying to sharpen...
To me, spade bits are a relic of the 1960s. I hate the things - Never have owned a single one.
So what do you use instead of spade bits ? Ship augers?I use self feeding bits for anything over an inch, spade bits for smaller holes (since the minimum size for self feeds is an inch)."I would never die for my beliefs because I might be wrong."
-- Bertrand Russell
I thought the $20 ones where the high end ones!!!!! I actually went out and bought another one, ~$16.00. Figured it is the more economical way to go ( me spending 2 hours trying to sharpen the thing and then it being just as dull as when I started).
To me, spade bits are a relic of the 1960s. I hate the things - Never have owned a single one.
So your saying you've owned multiples of them??!! Yuck, yuck, yuck.......boy am I funny..........
You can have your hole saws sharpened at any competent blade sharpener. Probably the same people who sharpen table saw blades, shaper cutters, etc. Yellow pages will get you there, but probably not by Monday!
Spades come in two varieties, spur on perimeter and flat. The cutting edge is where the vertical face meets the bottom edge. File so that the edge where they meet is sharp. Bit style will dictate where to file or grind.
PJ
Everything will be okay in the end. If it's not okay, it's not the end.
I would imagine that some of the guys that operate saw sharpening services would be able to sharpen hole saws. It wouldn't be too much different from sharpening a handsaw, except that a special jig would be required to hold it in the sharpening machine.
Here is a picture showing how to sharpen a spade bit.http://www.blackanddecker.com/ProjectCenter/DocumentView.aspx?DOC_ID=p_3_36_13936_13944_13960.htmlAnd an auger bit.http://www.blackanddecker.com/ProjectCenter/DocumentView.aspx?DOC_ID=p_3_36_13936_13944_13959.html
Sure you can. Both.
Hole saws can be sharpened with a 'three-square' file. A triangular for the uninitiated. If your really good you can get it close to brand new by eye, counting the number of strokes and using exacting care.
Mostly your better off buying a new one, they aren't very expensive, if you need precision and a smooth cut. Just go round the saw with the file forming teeth. I wouldn't worry about alternating rake, setting the teeth or worrying too much about getting the teeth exactly identical. You don't use this sort of bit for building pianos.
I do a lot of rough work and hole saws can take a beating. Having a sharpened backup, even if it is a bit rough, makes sense.
Spade bits can be ground or filed. Use a flat file if you want straight cutting edges. Some spade bits come ground with a spur that makes them cut a bit faster and cleaner. You can grind, or file, these off making a more conventional edge or use a rat-tail file and make the two edges scalloped.
This makes, once you do it once, for a fast cutting bit with large spurs that make for a clean cut. They wear fast but are easy to recreate. Worse case your out both dollars you spend for a new bit.
Spade bits aren't useless- in a situation where there are unknowns behind whatever needs drilling, it's easier to stop than an auger or self-feeding bit when it breaks through. Yeah, they get dull pretty easy when hitting nails, but they're easy to resharpen. Rattail and fine mill files or a fine grinding wheel, preferably a thin one with one side radiused. Then, tilt the bit a little when touching it up. If the spur was bent back it can be tweaked in a vise before resharpening.
"I cut this piece four times and it's still too short."
Spade bits are the easiest to sharpen. Use a file for your first attempts. Look at a new or properly sharpened spade bit. The point does not do the cutting, the lip does. The relief is about 10° ( this is the angle from the horizontal you hold a file).Place bit in vice or hold steady against a bench. Stroke file forwards while holding file handle down 10° ( the degree is not critical) take only forward strokes. The file cuts only on the forward stroke.Usually 3 or 4 strokes will sharpen a lightly dulled bit. Turn the bit 180° repeat on other side. If the point is badly worn file it too. Same angle but vertical.File each side same amount so the cutting lip is the same height. If the bit is badly damaged, file until the lip looks sharp, repeat on other side. Grinding is faster, when you understand how the bit should be filed ,then you can grind if you want.
A mistake I've seen ( and done myself) is to file the lip on too steep an angle. The bit will cut but wears dull quickly.
I sharpen hole saw bits with a dremel tool and a cylinder shaped chain saw grinding stone.Sharpen them so they look like a ripsaw tooth. Straight across, holding the dremel level. Push and pull the dremel in four times, each tooth same amount. Do all the teeth then check for sharpness. If it needs more repeat until you have a point that is sharp.
mike
The spade bits with the spur on the outside tip cut a bit faster and cleaner.
A compromise, once you have to sharpen a regular spade bit, is to sharpen the bit to form a bit of a "W".
I am looking for a good "V" pointed stone to fit the dremel. I will make a jig to hold the dremel, for sharpening a plethera of holesaws that need it.
I mean a pointed stone, of course, not one with a v cut into it. And I'll undoubtedly need more than one or two.
I'm off to google !
=0)
A person with no sense of humor about themselves, has no sense at all.