mortising white oak...getting my butt kicked

hi everyone,

just started working on a small outdoor structure, framed with green white oak. i have a boring machine and a low rpm drill but am having lots of trouble. in the boring machine i've tried a 1 1/2" bosch spur auger bit, i made it to the bottom but barely moving with all my might after about 3" depth. I tried that same bit in a low rpm drill and again after a couple inches it jams up, the bit got really hot and the spur chipped. i then have been using a milwaukee bit with the saw tooth edges, i believe its for a hole hawg, and that kinda works but it gets super hot and i have to pull out and clear chips/clean the bit every inch at least. and this is all with clear wood, no knots in sight.

also in the course of drilling peg holes, also with low rpm drill and auger bits, i bent two bits, one long one and one short 8" one, and got one stuck that had to be wrenched loose with a socket wrench and 6 foot pipe.

do people use special bits for hardwood? or have them sharpened specially at a different angle? kinda stumped here and would appreciate any insights or advice. other info is that im using a dewalt low rpm drill, not a high-end model...maybe i need more power?

thanks for reading
Jon Santiago

We went through this with black locust a couple of years ago. A brand new New Englad Twist Drill ship auger in 1.5" would not cut. It would go in a little ways, and then the bit would bind and heat up. Someone, not me! even tried a hammer drill bit for masonry, and made better, albeit smokey, progress. Eventually a local framer with a Mafell was called to bore the mortises. Aside from blowing the breaker twice per mortise, the mortiser cut the locust. I don't know why, but I never tried my boring machine. After it was all said and done, my boring machine with proper bit cut the black locust like a champ. I would look very closely at the Bosch bit, and see that it hasn't been sharpened on the outside, reducing the diameter near the cutter. That will surely bind things up. It also may just need a good going over with a file. I eventually got around to fixing the NETD ship auger and it bored the black locust just fine.

I bored a lot of holes in semi-seasoned white oak last summer. I did buy a Millers Falls boring machine, as I was worried my Swan would not survive. I used a standard boring machine bit. It was plenty of work compared to white pine, but no binding issues.

The Boss has a reduction gear. Look for bits with a very fine feed screw. I have a collection of bits with different feed screws that are used for different species. For sure proper sharpening is completely necessary.

thanks dave thats helpful, so why did the NETD bit not work the first time around? do you send out your boring machine bits or sharpen yourself? special file?

just want to clarify are there special bits for hardwood ?

Jon, in past generations it was the era of efficient cutting tools because hand powered cutting was prevalent. Today tools come in limited variety. In my view, your best bet is with spurred auger bits, not the so-called nail eater bits. You need the spurs in order to cut clean sides in the bore. The feed screws are generally coarse. The drill must be slow speed 300 to 400 rpm. If you are an old tool hound and are looking for boring machine bits then fine feed screws are key. Sharpen with an auger file, also getting hard to find. So good luck.

I've been boring and cutting well seasoned -like 120 years- native hardwoods of mixed varieties over the last few weeks. Like Dave said, having the right it helps a lot. A 1 1/2" boring machine bit is pretty easy really, but you do get pretty tired after drilling too many in a row (don't try and cut all your mortises in one go, break it up with other work) and driving a 2" bit through well seasoned ash is the best shoulder and tricep workout ever devised!

I think as per your question about bits, the important thing is the thread on the screw. A finer thread will try to cut out less material with each pass, so is well suited to hard wood. But it may simply strip out in too soft of wood. I run into that problem in reclaimed wood, where there may be a hidden pocked of soft wood (water damage, for example) and the screw will strip out.

I wish for a much finer thread on my 2" bit


I use a file on all my drill bits, it's pretty easy, just make sure you know each cutting surface is only sharpened on one face.

You can get new double flute, bottom side cutter bits, I have not seen 2" but have 1-1/2" which I use, the feed screws on these bits are not fine, I would say it is a medium and they cut a nice clean hole. In hard wood I would use my Boss Double Eagle on the low gear. New to me is my adapted electric version of the older boring machine which I have taken to quite well. On this set up I am using a 2" boring machine bit with extra course feed screw in white pine. https://www.youtube.com/watch?v=n5mNevktPJA

timbeal who makes the double flute bits you mention?

I don't recall exactly, I will have to look and see if there is a stamp on them some where, I think they were Irwin . When I did pick them up at the store the owner said they were being discontinued from the manufacture, so I bought the last two they had. But here is a link to a similar and not too bad looking bit, there are others out there worth searching. One issue is the length, if you are doing deep holes, 5+inches they won't clear the chips well, they are fine for 4.5" deep holes.
http://www.milwaukeetool.com/accessories/drilling/48-13-1500#

Here is the Irwin bit I believe I have, looks like they still make them. I cut the taper off the end and hand a machine shop make solid shank adapters for them and I welded that to the bit for extra length and to fit the 1/2" shank for the boring machine, this is why the stamp may not still be intact.
http://www.irwin.com/tools/drill-bits/hand-brace-solid-center-auger-bits

An update and for future reference of future dummies like me: we had an old 1 1/2" brace bit that we cut the tapered end off and ground the end lightly until it fit in my boring machine and it was like night and day with my previous experiences. cut like butter, even though the bit is slightly bent and wobbles. my takeaway is that the flute edges are much thinner than the modern auger bits and thus have less surface contact to bind up. also their are two chiseled cutting edges instead of one. also no spurs, but still a clean hole. also could confirm the previous comments about differences in threads on feed screw. i've been feverishly searching the web for old 1 1/2" brace bits and/or boring machine bits and seems like there are precious few out there.

TIMBEAL, I'd like to buy that Irwin brace bit and do the same thing I did with my antique bit...do you know the diameter of the shank past the tapered end? can't find this info anywhere. if its 1/2" or greater I know I can work it down to fit the machine.

thanks everyone

Boring machine bits should be .500". I've had some that were cut down T-augers, and they were too small, like .440", and you can never get them to chuck in the machine nicely. You should be able to straighten your bent bit. I'd wrap the shank end in something soft, like sheet copper, and clamp it in a vise and gently bend it in the direction it needs to go. I've even grabbed a bit while it was in the boring machine and given them a tweak, but that is risky.

The shank on mine was smaller, so the adaptation. A new shank with a hole in one end and the other 1/2" welded on. I wrapped the cutting end in a very damp wet rag.

I have smacked warped bits with my leather hammer with some success, at least it was better than it was.