Drill press mortise attachment

Tim Sherwood

Tim
Corporate Member
I have tried to use the square chisel mortising attachment on my drill press several times. I never got it to work right. Now I have a project that requires dozens of double mortise and tenon joints. So I dragged the parts out of a bottom drawer and got serious. I'm pretty sure I have it all assembled right , this time. But it's still not working.
When I turned the drill on, it sounds fine. The drill bit is not draging or rattling around inside the chisel. But when I plunged it into wood, the drill bit pulled out of the chuck. So I tried again. I noticed that the chuck , which is only a year old, took a lot of cranking to seat tighty to the bit. This time when I started a cut, the chuck broke loose from the tapered shaft. I figure that there is a miss alignment putting side pressure on the chuck.
I've checked the run out with just a bit in the chuck, and that is fine. The long mortising drill bit seems to be straight too. So all I can figure is the cast iron yoke that holds the chisel has a problem. This thing has to mount perfectly onto the quill collar . Then the chisel has to be held in perfect alignment with the chuck and the drill bit. Has anyone been able to make this miracle happen?

Can this perfect alignment be achieved? Should I give up and buy a dedicated mortiser; drill and chisel the mortises; make a mortising jig for a router??
 

Bas

Recovering tool addict
Bas
Corporate Member
Tim, I don't own one, primarily because I read Tom Hintz' review many years ago -> Drill Press Mortising Attachments - NewWoodworker.com LLC
I suspect you're better off getting a dedicated mortiser, or use the time you'd have spent fiddling with the drill press attachment for making a mortising jig instead.

Mortisers show up on Craigslist every so often for a reasonable price, although things obviously have been slow the past month.
 

creasman

Jim
Staff member
Corporate Member
I have an old Delta drill press that was my father's. I also have the mortising attachment that goes with this drill press. The drill press I still use on a regular basis, but the mortising attachment hasn't been on it for several decades now. It works, but I find these drawbacks:
  • It takes a fair amount of time to attach all the parts and get everything aligned, as you know. This means I'm never going to use it unless I have a LOT of mortising to do. The time to setup and restore is more than I want to invest. Instead, I choose to drill out the bulk of the mortise with the drill press and finish the rest with a chisel.
  • When I have used it I remember having to go slow and keep the bit and chisel free of shavings. For the smaller mortises (say 1/4") this was problematic. The trick is getting that first square hole to depth, then it becomes easier to nip off a bit more each time. Before getting the hang of this I split a couple of the chisels -- a costly lesson.
My advice is if you have a lot of mortising to do, or simply don't want to do any work with a hand chisel, then get a dedicated mortising machine. I kept the attachment in part thinking that I might some day get a new drill press and convert the old one to a mortising machine with the attachment permanently installed.

If I were doing woodwork for a living and owned a production shop, then I'd probably invest in one. For me, I enjoy using hand tools as much as possible and often use a mortising chisel only. It takes a bit of practice but it's worth the effort when you create a mortise of uniform width and perpendicular to the face. If I have a lot of mortising or don't want to risk being off square I'll drill the bulk out then use a paring chisel to remove the rest. Also, keep in mind you can leave the ends of the mortise round and round the tenons, instead. That's often easier than squaring the holes.

Hope you find the right solution. If you decide to buy Bas offers a good suggestion in finding a used one. I've seen 2-3 of these at estate sales over the past year or so.

Jim
 
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bob vaughan

Bob Vaughan
Senior User
From what I've seen, the Asian-made presses and mortising attachments are not the same as the old USA-made stuff. The USA-made presses like Delta and Powermatic had mortising attachments that worked fairly well but not as good as a floor-standing hollow chisel mortising machine by any stretch. Modern Asian-made presses are built to address a price point. Saying all drill press mortising attachments are not adequate is too broad of a brush. The USA-made presses are generally an exception but there aren't many of those available these days.
 

Tim Sherwood

Tim
Corporate Member
Thanks for the feedback guys. I totally agree with the video you linked Bas. That was fun. I don't think I would use a mortiser often enough to give one space in my little shop, even if it was a used one. My drill press and the attachment are both Asian made. As Bob pointed out , tight tolerances may not be their goal. Like Jim suggested there are other, if slower ways to cut a mortise. I think I'll use this excuse to try both the router and drill press methods.
 

Gripbd

BD
User
It sounds to me that the bit is self feeding into the piece faster than you can push the chisel. A dedicated mortiser has an arm that is 3 to 5 times longer than the typical drill press arm, and also a lot beefier to allow you to force the chisel through the wood. I suppose you could try to rig an extension to the arm to give you more leverage, but there’s a chance you’d damage the drill press. (Bend or even break the arm? Strip or break the gears? The gear track on a mortiser is also a lot beefier.) I don’t think that you have problem with alignment, but are trying to use the drill press for something it wasn’t designed to do.
 

Charlie

Charlie
Corporate Member
Tim, Did you experience the same problems with the "old" chuck? If not, do you still have the old chuck?
I used the same setup on my Craftsman drill press from the early 70's with no problems.
I don't know if you have installation instructions, but if you don't:
When installing the chisel and bit, slide the bit into the chisel and then the chisel/bit into the chisel housing/chuck. Leave about 1/16" between the stop on the chisel and the housing and tighten the locking screw. Tighten the chuck onto the bit ( I would investigate as to why the chuck is difficult to tighten onto the bit) . Loosen the chisel locking screw and slide the chisel up into the housing and lock in place. This allows 1/16" clearance between the chisel and the bit. Some instruction call for 1/16" - 3/16" clearance.
If this info doesn't help, bring your pieces to my shop and you can use my Delta bench top mortiser.
 

bob vaughan

Bob Vaughan
Senior User
I used the same setup on my Craftsman drill press from the early 70's with no problems.

That era would make it a USA-made press, made by Emerson Electric most likely. Sears didn't start using the Asian imports until the 1980s IIRC.
 

vinson

Doug
Corporate Member
I just bought a Mortise Master in order to switch from traditional M & T to slip tenon joints. The jig is very versatile and super easy to use.
 

Dee2

Board of Directors, Vice President
Gene
Staff member
Corporate Member
Used my drill-press mortise attachment yesterday on the Delta DP. Worked as expected. Might be 3rd or 4th time I've used in since getting the attachment in the 80's. Had to clean a little 'patina' from some of the parts. The chisel fits really tight in the collar. Oh, had to remove the keyless chuck and installed the keyed chuck.

So, it can be done from my experience.
 

Tim Sherwood

Tim
Corporate Member
Great info . I'm really pleased that so many NC woodworkers took the time to give this some serious thought!
BD I think you are onto something I had not considered. I was trying NOT to push the chisel hard into the wood. That could easily caused the drill bit to pull the chuck off it's taper. I know I shouldn't over stress my import drill press. Those of you who have had good results appear to be using better quality, US, machines.

Charlie, I thank you for the offer to use you equipment. But for the next few months, I'm not planning on any road trips

Doug I just looked up that mortise master jig. It looks like he has designed a really good one. I like the approach of using loose tenons. I think I'll use this forced down time , to play with the different mortising techniques.
 

Dee2

Board of Directors, Vice President
Gene
Staff member
Corporate Member
For hand chopping a mortise, check out Paul Sellers on YouTube. Others may disagree with what he does.
 

vinson

Doug
Corporate Member
Paul Sellers is my hero, but I am just to old to take time to cut mortises by hand. As I mentioned I have the Mortise Master but the Morley looks good too. The perfect offset feature of the MM is amazing.
 

Willemjm

Willem
Corporate Member
I have tried to use the square chisel mortising attachment on my drill press several times. I never got it to work right. Now I have a project that requires dozens of double mortise and tenon joints. So I dragged the parts out of a bottom drawer and got serious. I'm pretty sure I have it all assembled right , this time. But it's still not working.
When I turned the drill on, it sounds fine. The drill bit is not draging or rattling around inside the chisel. But when I plunged it into wood, the drill bit pulled out of the chuck. So I tried again. I noticed that the chuck , which is only a year old, took a lot of cranking to seat tighty to the bit. This time when I started a cut, the chuck broke loose from the tapered shaft. I figure that there is a miss alignment putting side pressure on the chuck.
I've checked the run out with just a bit in the chuck, and that is fine. The long mortising drill bit seems to be straight too. So all I can figure is the cast iron yoke that holds the chisel has a problem. This thing has to mount perfectly onto the quill collar . Then the chisel has to be held in perfect alignment with the chuck and the drill bit. Has anyone been able to make this miracle happen?

Can this perfect alignment be achieved? Should I give up and buy a dedicated mortiser; drill and chisel the mortises; make a mortising jig for a router??
Tim, I use a dedicated mortising machine, bench top. Even that his it’s limitations. Anything more than 3/8”s of an inch, one needs considerable force to sink the mortising chisel. More than what a drill press could handle. If I do 3/4” I go to the drill press first with a forstner bit, then back to the mortising machine.
In short, you will be better off using a forstner bit on your drill press and then clean up with a chisel.
 

Ed Fasano

Ed
Senior User
I have an old Delta attachment that I've used on occasion on two diffident drill presses. Its now been years since I used it though. While it worked reasonably well, the setup and the process was imprecise and annoying. I have since resorted to various other mortising methods, including a router, a router table and mortise chisels. Back to the point though.. Perhaps a process of elimination might shine some light on the problem. Using the components in an additive sequence might help. In other words, does the bit by itself pull free from the chuck.... and so forth.

Are the sides of the chisel body well-polished? Has the bit-to-chisel relationship been set to ensure that the end of the bit is NOT rubbing against the chisel opening? Metal-to-metal contact there will generate a lot of heat. That heat might be reacting with the wood and its resins, causing the chisel to bind. Lastly, I recall using a spray bit lubricant when using that mortising attachment. Perhaps that helped me more than I know.
 

Dee2

Board of Directors, Vice President
Gene
Staff member
Corporate Member
Paul Sellers is my hero, but I am just to old to take time to cut mortises by hand. As I mentioned I have the Mortise Master but the Morley looks good too. The perfect offset feature of the MM is amazing.

Paul, if YouTube is real time, can apparently cut a mortise faster than I can install the mortise attachment to my DP! LOL! Confident I'm certainly not that fast. I've been trying to mortise bowties into a 14' pecan bowl. It's like work!

Oh, and I added 3in1 oil in the chip release slot about every 3-4 plunges (1/2x1/2x full depth of DP) to cut down on friction/noise. The wood was pecan. Yeah, I've had a bunch of pecan.
 

Johnson

New User
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I have used an MDF template with an up spiral bit in my plunge router with a bushing to great success. It takes a little bit of time to fine tune the template, but I save them in the different sizes for future uses. If the tenon is going to be exposed, I will square up the mortise with a chisel. I have also just rounded over the tenon with no issues.

Is anyone else a fan of this approach? I obviously don't have a Domino.
 

Tim Sherwood

Tim
Corporate Member
More good thinking! I have given up on the attachment idea. I tried the drill and chop method this morning. . I used a 1/2" forstner bit to try to cut a 1/2 x 3/4 mortise. That was too much overlap for the second hole. The bit wanted to push into the first hole. I'm sure it would work better for a 1/2 x 1 mortise. Even so, after squaring up with my chisels the mortise was both wider and longer than I wanted. So I tried aiming at the same mortise size but using a 3/8 drill. That let me drill inside the layout lines, but left more chisel work. It's going to take a bit of practice!

I'm going to explore the multitude of mortising jig plans next.
 

zdorsch

Zach
Corporate Member
Another option only requiring a router using some scraps:

74240931-AA20-4E7C-ACEC-4F762C8573D6.jpeg


While this is my jig, the design was found years ago on this site or one of the others. I originally used a piece of plexiglass, but dropped it. The jig is a little fussy to setup, but once set maintains its setting.
 

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