sharpening drill bits

Does anyone know how, or know where I can get my 3/8" SDS drill bits sharpened?

thanks,
Chris
520-548-6652

It seems like you could just use a file? I don't know, it seems like you might change the diameter of the hole if you file it too much.

Chris, I swiped a glass grinder that my wife had for stained glass. It has a small silica carbide wheel that works great. I've been able to get about 10 times as many holes out of a bit as would otherwise be possible. The resharpened bits don't last as long as brand new ones, but then you just resharpen them. It's good to try to maintain the original angles on the bits. I doubt that a file will be that effective on carbide tipped bits. Any hobby glass store should have the grinders for about $40. Also, if you have a regular grinder, you may be able to get a silica carbide wheel for it.

I haven't tried this and it's for modifying bits for drilling rivets, but in Rock & Ice #86, page 44, they have a how-to on modifying bits with a grinder. Maybe the same principle doesn't apply but I'm just throwing it out there. Anyone know if you can do the same thing to re-sharpen SDS bits?

Thanks for all the replies. I am going to buy a drill Doctor 350. I found it on line for $49 and I am hearing that it will sharpen in a jiffy. I also heard that using SDS bits that after a couple of sharpeing the hole drilled gets too small and it becomes impossible to drive in a wedge anchor. Perhaps a five piece rawl might still fit.

Chris Craig wrote:Does anyone know how, or know where I can get my 3/8" SDS drill bits sharpened? thanks, Chris 520-548-6652

Use a green wheel or a flat file, and, only sharpen them across the end, and, try not to touch the sides. Then measure the sides to make sure they still are big enough to drill a proper hole (usually not, they wear just as much in diameter across the tip).

Toss 'em if they are too small in diameter. Especially if you're using Powerbolts.

-Brian in SLC

And before you go get a sharpener, make sure that you don't have a bunch of the newer SDS bits where they have multiple angles/notches on the bit tip.

The drill manufacturers claim it improves performance, but the notched tips are actually designed to prevent resharpening and thus increase sales.

I don't think using a drill doctor is a good idea... the SDS bits use a different profile on the tip than do the bits the drill doctor is designed to sharpen. I've used a bench grinder before with good results.

You can buy new 3/8" x 6" SDS-plus Rockhard hammer drill bits from Missouri Precision Tool
for $4.37 each.

It may be better to buy new bits than to pay $50 for a sharpening device and get less-than-perfect results.

If resharpened bits get somewhat worn in diameter it is still possible to use the bit by churning the bit slightly in the hole to get a 3/8" hole. It doesn't take much practice to get the feel of what you need to do in various types of rock (harder rock needs less churning). It's easy to tell when driving the bolt if the hole is the right size as you shouldn't have beat the hell out of the bolt to drive it, nor should it go sliding in with one or two hammer blows. I have found Rawl 5 piece bolts hard to drive at times, even with brand new bits.

Tzilla Rapdrilla wrote:If resharpened bits get somewhat worn in diameter it is still possible to use the bit by churning the bit slightly in the hole to get a 3/8" hole. It doesn't take much practice to get the feel of what you need to do in various types of rock (harder rock needs less churning).

My experience with worn drill bits hasn't been as good. I've tried the churning technique to enlarge too-small holes, and failed to make the hole diameter large enough after several minutes of effort (Boulder Canyon granite). The sleeve on the wedge bolt still hung up on the lip of the hole. I've ruined several bolts this way. Maybe if I had resharpened the worn bit I'd have had better results.

WIth new bits available for under $5, I'm going to continue to buy new bits instead of resharpening old ones. This is small change compared to the money I've spent on bolts, hangers, and anchors. YMMV.

Could just work in the construction business and pilfer them from your jobs' operating budget.

Possibly consider using a medium and fine diamond file. These can be purchased online at tognar.com which is a ski tuning equipment supplier.

Most SDS bits are carbide tipped. The best results I have achieved in sharpening SDS bits is with a set of diamond files. Diamond files are great for the money and have many uses.

As stated in a previous post it is very important to remove the minimum amount of material when you sharpen an SDS bit as it is super easy to mess up the gauge/taper.

In light of the fact that new bits can be found as cheap as $5.00 it makes sense to trash a used bit. Rawl/Powers Five Piece Bolts will be the first to not fit an out of gauge hole with Redhead Torque Out Bolts being the most likely to fit. Any Hilti Bolt will be a very tight fit likewise.

Ron Olsen wrote: My experience with worn drill bits hasn't been as good. I've tried the churning technique to enlarge too-small holes, and failed to make the hole diameter large enough after several minutes of effort (Boulder Canyon granite). The sleeve on the wedge bolt still hung up on the lip of the hole. I've ruined several bolts this way. Maybe if I had resharpened the worn bit I'd have had better results. WIth new bits available for under $5, I'm going to continue to buy new bits instead of resharpening old ones. This is small change compared to the money I've spent on bolts, hangers, and anchors. YMMV.

I agree with Ron's comment!
I don't believe it is worth the trouble resharpening. My Partner and I were resharpening approx 2 times per bit and they just didn't last as long. Paying $3.50 per bit saves a lot of time and hassle's, not to mention that the smaller bit size botched several placement's :( Also most important of all is when you are developing some area that requires a long hike in you want to make the most out of your batteries power. The last area was over $1,000.00 in hardware so spending $50.00 on bit's was "nothing." Nothing is more annoying when a placement is botched..... I alway's thought everyone on the Mt.could hear me cursing at the top of my lung's F***K

One quick note on the whole churning thing. I found out years ago [the hard way, of course] that any movement other than directly "in" on a drill dramatically wears components in drive train that would otherwise last a very long time. Bearings and, eventually, motor brushes can be worn out very very quickly by 'churning' the drill while drilling. The absolute worst thing you can do is push the drill to one side in an effort to wallow the hole bigger.

I'm sure most of you know this but wanted to throw it out to clear my conscience. The tech i took my drill to knew exactly what i did to it as soon as he started taking it apart.

Sharpen them all the time on a standard grinding wheel. When they get too narrow I throw them out. It does save a lot of money even if you only get another 20 holes. Never thought about the bushings and bearings getting worn by wallowing out the hole. I don't usually do but my partner does all of the time. Bugs the shit out of me. Now I have an argument for not doing it. Thanks Daryl

Eric, have you had any luck sharpening the newer sds drills with the multi-angled tips? I have a couple that i won't throw out thinking i'll one day take a stab at sharpening them. Should i just go at them as if i were working on the older types eventually making them look like the simpler tips? Btw, the cheapest place i've found bits is at Lowe's; they had the the 3/8" for $6.49 each a couple of months ago. I stocked up.. =).