Replies

1. 
   Jamie_Buxton | Aug 23, 2004 12:15am | #1

   Hmm.   That's not my experience.   You could try giving yourself a little more clearance between the bit and the chisel.   And, of course, make sure the bit is sharp.

2. 
   Steinmetz | Aug 23, 2004 03:27am | #2

   Kiddo, try 'Stabbing' the hole as you bore, to facilitate chip removal

    Also attach a foot switch to the drill press/mortising machine to oscillate the the drill's speed at the same time.

   Sharpen or hone the bits and use compressed air to keep the heat down.

   Steinmetz.

3. 
   bill_1010 | Aug 23, 2004 06:29am | #3

   Make sure all is sharp, both bit and chisel. And make sure it doesnt have build up pitch and gum.  Set up a shop vac to pull out chips and shavings.  

4. 
   Jellyrug | Aug 23, 2004 10:23pm | #4

   What kind of lumber are you working with?

5. 
   scooter1 | Aug 23, 2004 11:12pm | #5

   I have had the same problem. If you are using a Delta rig, Delta has three different types of chisel and bit set ups. Beginner, made by coolies in rurual China, part no. 17-1780. This p i e c e ' o ' c r a p is equivalent to the Jet bits that sell for $14-10, although Delta gets $25 for theirs. The intermediate bits are made in Austria and are part number 17-184 and sell for about $35, and are supposedly better steel. The finest are 17-908 and are made in Germany, and are $45 a piece.

   Delta sells replacement quarter inch bits BY THE PAIR which ought to give you an indication that they fail often, right? That part number is 17-916, and is about $30 for a pair of bits.

   That being said, the quarter inch bits heat up in any kind of wood and simply are too small for all day use. Once they heat up, they lose their temper and break. The German made ones are marginally better than the el cheapo Chinese ones, but I find it hard to justify almost triple the price.

   I think you are good for about 15 mortises (downstrokes) then let the sucker cool down for 30 minutes; You could pre-drill the area with a 3/16ths bit, but what a pain. I just let mine cool down.

   I get mine on Amazon for $12 for the chisel and bit. The bit is too long, and I hack saw them off, and throw away the chisel.

   So go slow and buy cheap replacement bits and have a large supply on hand for these small ones.

   Regards,

   Boris

   "Sir, I may be drunk, but you're crazy, and I'll be sober tomorrow" -- WC Fields, "Its a Gift" 1934

6. 
   mike4244 | Aug 23, 2004 11:16pm | #6

   Your speed may be to fast. First slow speed down to 500 rpms or less. Use spray lube like Dricote every so often. Dricote does not stain or interfere with finishes. When bit is dull ,remove and sharpen. You will need a flat narrow file , auger bit file or needle file to file the lips. Touch up the inside of the spurs . The auger bit lips should extend past the chisel a sixteenth of an inch.

   mike

7. 
   KesslerCraftsman | Aug 24, 2004 04:49am | #7

   I use 1/4 x 1/4 quite a bit..and have never had to replace a bit.  Is your drill press running true?

   I use the English mortising bits...around $65 apiece....they're expensive but good.....

   Check your drill press runout.

   Then make sure there is adequate clearance between the bit and the chisel.  You should be able to run the bit all day (without mortising anything)...without the chisel heating up.  If the chisel heats up when you're "free-running" it, your drill press isn't running true OR the clearance is inadequate.

   Finally, go slow and allow the chisel to cool down a touch between mortises..and "stab" or take small bites....works for me.

   Good luck!

   Larry Pile

1. 
   Scooter456 | Aug 24, 2004 06:20pm | #8

   The mortiser is a Delta mortiser, with which I have absolutely no problem with in 4 years I have owned it, and is wonderfull.  There is no problem with any other type of bit, only the quarter inch.  The wood is black walnut.

   I have slowed down a tad, shutting off the machine every 5-7 strokes and vacuuming out the chips and checking the temperature of the bit.  If it is cool enough to place my finger along side of the chisel and hold it there, then it is cool enough to operate.  I switched from the German bits to the Chinese, and saw no difference in performance.

   Ultimately this is a case over probably going too fast and not letting the bit cool.  The larger bits seem to dissapate heat better.

   Thanks for the tips, guys.

   Kelsey

2. 
   Jellyrug | Aug 24, 2004 06:53pm | #9

   Larry,

   Where do you purchase these English speaking bits? Will appreciate a source.

   I have no problems with the El Cheapos from Grizzly (think they speak Taiwanese with a smokey breath), but can do with a cleaner cut.

   Willie

1. 
   KesslerCraftsman | Aug 25, 2004 02:19am | #11

   Hi Willie,I hate to admit it, but Woodcraft...I needed the bit and they're the only game in town..until recently (thank you,  Rockler!!).

   The brand is marked "Clico (sheffield) Tooling, Ltd" with an English address.  I paid $64 for the 1/4 one around 2-3 years ago.

   It's also worth it to get the little conical sharpening stone for sharpening the chisel...it's $20 but sharp chisels are worth that.....

   Good luck.  e-mail me at [email protected] if you have further questions.

   lp

1. 
   nikkiwood | Aug 27, 2004 12:45am | #12

   What's your technique for using the conical bit to sharpen the chisel?

1. 
   AlanTurner | Aug 27, 2004 04:45pm | #13

   I use the LV daimond cone, and put the chisel in a drill press vise, at true vertical, and them mount the the cone in the chuck. Go slow, and have a water mister handy. Only takes a sec. Raise the burr, and then carefully lap the sides.Alan

   http://www.alanturnerfurnituremaker.com

2. 
   nikkiwood | Aug 27, 2004 05:15pm | #14

   Thanks for info, Alan......

   I don't have a drill press vise. Is there any other way (to hold the chisel), or is it time to buy the vise?

3. 
   AlanTurner | Aug 27, 2004 07:12pm | #15

   Any kind of a machinist's vise would work, I suppose, but a drill press vise is cheap, and occassionaly quite useful. One should never avoid tool acquisition. ( :Alan

   http://www.alanturnerfurnituremaker.com

4. 
   joinerswork | Aug 28, 2004 07:27am | #16

   nikki,

   I clamp the chisel vertically in my bench vise, chuck the cone-stone in cordless drill.  It self centers, no problem.  Hold it vertical, touch it gently to the chisel opening. Piece of cake.

   Regards,

   Ray

5. 
   nikkiwood | Aug 28, 2004 06:53pm | #17

   I like your idea (bench vise, drill) -- but isn't it difficult to get an even grind?

   Anyway, I have some old, cheap chisels in need of sharpening -- and I'll try the technique with these before I pull out the Clicos. And if my old fumble fingers can't do it right, then I guess it is time to acquire a drill press vise.

   Thanks to you, and Alan .................

   Edited 8/28/2004 11:54 am ET by nikkiwood

   Edited 8/28/2004 1:12 pm ET by nikkiwood

6. 
   joinerswork | Aug 30, 2004 05:02am | #18

   nikki,

   I never really spent a lot of time trying for a perfect grind, just run the stone in the end of the chisel till I raise a bit of a burr no all 4 sides. It centers itself.   A light swipe across the bench stone gets rid of the burr.  Careful, don't taper the outsides of the bit. ( I run a small tricorner file in the groove in the corners to clean them up.)

   I can't see that it needs to be PERFECTLY even.  In use, the bit is hogging out the bulk,then the chisel shaves/pushes the rest of the waste into the bit for removal.  Pretty down and dirty process, seems to me.  Of course sharp will work better, and reasonably even across the 4 points of the chisel will keep it from wanting to lead one way or another.

   Regards,

   Ray

8. 
   JohnWW | Aug 24, 2004 08:28pm | #10

   Kelsey,

   Assuming everything is sharp and running true, there are a few things to try that will help to cool things down.  1/4 inch bits have the most trouble with overheating because they have little room to clear the chips through the chisel.

   Turn the chisel so the chip port is to the side rather than pointing towards you or the fence. After making the two end plunges first, do the remaining clean out cuts so the chips exit to the side into the part of the mortise you have already cut.  The chips need somewhere to go, otherwise they pack inside of the chisel and generate heat.  Stop and clean out the mortise as needed to leave room for the chips.

   Because the first two holes at either end of the mortise won't have space on the side to clear the chips into, predrilling them will cut down heat build up.  Use a 3/16 bit to predrill the holes. 

   Make sure the chip port is as smooth and wide open as possible, use a Dremel Tool with a small stone to clean up the port if needed.  Also lightly grind back the sides of the chisel above the bottom of the chip port, this will reduce the force needed to plunge the chisel, only the tip below the port needs to be full size.

   Don't overlap the holes, move over the full quarter of an inch for each cut.  If you are taking partial cuts, the bit gets forced to the side and rubs against the inside of the chisel, generating heat.  If the final section to be cut is narrower than a quarter inch, center the bit on the section.

   Use a spray lube such as Dri Cote.  Spray it through the chip port so the lube gets on the inside of the chisel to make chip clearance easier.  Use it frequently.

   There is nothing gained by having the bit just barely projecting beyond the chisel, try lowering the bit some to give more clearance between the bit and the chisel.

   Don't linger in the cut, plunge in as fast as the bit and chisel will go and back out the moment you reach full depth.  The longer the bit is in the wood the hotter it will get with nowhere for the heat to go.  Each cut should take only a few seconds.  If you've never done it this way, this tactic will seem fast and aggressive but it will greatly reduce heat build up.  Because they don't have good leverage, this is harder to do on drill presses and bench top machines. 

   If you are using a variable speed tool, use a moderate speed, around 1,800 RPM.  If you try to do a fast plunge at a slower speed, the chips are too coarse and will have trouble moving though the chisel.

   If you are still having heat build up problems, very lightly misting the bit with water will cool it down between cuts, but don't get the wood wet, that will make cutting more difficult.

   Hope this helps, John W.