# Using a drill press mortising attachment



## Stevedore (Dec 28, 2011)

I'm making a small Mission-style table with through-tenons where the lower stretchers go into the legs. I'm using my drill press with the Delta mortising attachment, which I've never used for a real project, only for testing to see how it worked.

I made the mortises last night, and wasn't real happy with the process, although they should be OK. I'm using the 1/2" chisel/bit set, and it seemed to take a LOT of pressure to force through the wood. (Red oak) Shortly into the cut, I got lots of smoke! I had the press set to around 1000 rpm, so lowered it to 600 for the next cuts, but still seemed to get a lot of overheating.

Is this normal, or am I doing something wrong? The chisel set is either brand new, or used once when I played around with the thing a while ago. I set the chisel to allow about 1/32" clearance for the bit, per the instructions. 

I'm thinking next time I may drill out the mortises & square the ends of the holes with a chisel. 

Any suggestions would be welcome! I'm cutting the tenons on the table saw today, and hoping for that process to go somewhat better.


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## woodnthings (Jan 24, 2009)

*sounds familiar*

I just spent several days using a benchtop Powermatic 701 hollow chisel mortiser, a heavy duty machine for it's size. I had the same trouble as it would go in about 1/4" and "bottom out" or so it seemed. After a few calls to tech service, they assured me it was operator error and to play with the chisel height a bit and then bear down on the handle and plow through. Your bit sounds like it's up too far, a 1/16" would be my suggestion. A drill press is not made to apply a lot of downward pressure, since the rack and pinion is not beefed up for that, so apply pressure, but don't use body weight..... :no:
Mine spins at 1750 RPM so I'd go back up to the higher speed. Other benchtops spin at 3450 RPMs which I felt was a bit too fast, but others have good luck with them. So try that and see what you get. I also used a Forstner in 1 1/8" to prebore a hole and then hand chiseled the corners for some Mission style chamfered plugs in walnut.


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## Stevedore (Dec 28, 2011)

Thanks; I left the attachment on the drill press, so I'll go try the 1/16" & higher speed on some scrap later & see what happens.

Nice looking project you have going on there! :thumbsup:


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## Moorewoodwork (Jan 2, 2012)

Try lowering the drill bit a little , the chisel should just be cleaning up the sides , the bit should be doing most the work.

Sent from my iPad using Wood Forum


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## jersey hammer (Feb 7, 2012)

I know this is off topic but how did you make those walnut "pegs"? (lack of a better word) They look perfect if it's too lengthy to explain I understand.


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## woodnthings (Jan 24, 2009)

*I racked my brain..*

I consulted 2 other experts, tried various methods using the tablesaw.....scary.... and finally used a bandsaw. It required 2 fence settings for the step and shoulder and I freehanded the bevels. Then I sanded out the saw marks on a disc sander. I made them one at a time from a long section of walnut 1 1/2" sq. I was pleased with the results. 
I tried a combination of rips and 2 bevels and crosscuts on the table saw got close. I could have separated them on the bandsaw and finished the 2 remaining bevels, but the grain was going the wrong way, long, and it needed to be end grain. 
 bill


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## HowardAcheson (Nov 25, 2011)

Did you provide the appropriate clearance between the end of the drill and the mortising chisel?

First attach the chisel holder to the drill press quill. Then put the chisel into the holder using a dime between the chisel holder and the top of the chisel. Tighten the chisel holder on the the chisel. Next, insert the drill bit as far into the chisel as it can go. Tighten the bit. Now loosen the chisel, remove the dime and fully raise the chisel into the holder. Tighten the chisel in the chisel holder. The dime establishes the proper clearance and you should not get any burning. If you do give it slightly more clearance.

Another point, you should hone the the four outside surfaces of you chisels. Use the same tools as you would use to sharpen you hand chisels and/or plane irons. Work up through the grits until you have a polished surface. This allows the chisels to more easily enter the wood and slide back out.


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## woodnthings (Jan 24, 2009)

*Just who is "you", me?*



HowardAcheson said:


> Did *you* provide the appropriate clearance between the end of the drill and the mortising chisel?
> 
> First attach the chisel holder to the drill press quill. Then put the chisel into the holder using a dime between the chisel holder and the top of the chisel. Tighten the chisel holder on the the chisel. Next, insert the drill bit as far into the chisel as it can go. Tighten the bit. Now loosen the chisel, remove the dime and fully raise the chisel into the holder. Tighten the chisel in the chisel holder. The dime establishes the proper clearance and you should not get any burning. If you do give it slightly more clearance.
> 
> Another point, *you* should hone the the four outside surfaces of you chisels. Use the same tools as you would use to sharpen you hand chisels and/or plane irons. Work up through the grits until you have a polished surface. This allows the chisels to more easily enter the wood and slide back out.


:blink:
If so, yes I can adjust the clearance in my sleep now. The Powermatic comes with integral shims that hinge under the chisel, using either 1 or 2 or both depending in the size of the chisel. It also comes with a diamond "cone hone" mounted on the support column. I cut more flesh than wood the first day. Those buggers are way sharp.... and do not move your hand under them at anytime. :no: bill
BTW, You can see from the photos I did get it to work rather well as a matter of fact.


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