I have been using mortising machines for a while now, and continue to have the same problem with each one. I try to make a mortise in cherry or oak, and the tip of the drill gets clogged up with chips of wood, and then burn or smoke while drilling. I have tried different speeds and try to stay within the speed that the tools recommend but still the problem persists. Since the tip of the drill is a brad point I figure that predrilling the hole was not intended. I wondered about lubrication on the drill, but figure that will not be good for glue. Any ideas or suggestions? I did do a search in knots and all that I find talk more about what machine is best and the like. I’d rather not continue making mistakes and just living with them because I can’t find the answer on my own.
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Replies
What machine do you have?
I have a Delta drill press and Delta mortising adapter that I use now. I also have a cheap stand alone machine that looks a lot like a Jet, but for sure isn't that good. Thing is no matter what the machine, I get the same problem so I figure it must be my technique or something I am missing in the process. It would be nice to find a video that shows how to set up a generic chisel set up and see the tricks that go with it.
See the link below for a simple way to set the bit-to-chisel clearance. Getting this right is very important and can cause the jamming of chips you describe. This may not be the only reason, but it is an easy one to remedy to at least eliminate it.
http://www.newwoodworker.com/setupmort.htmlTom Hintz
Because there is always more to learn!
Thanks!! That is exactly what I need to be sure I have the thing set up right, and I can see where I don't. Maybe that will help my problem as you suggested. I have a feeling that will be the cure. Like the site said, the instructions to most machines are less than perfect, usually confusing, and this article sure clears up the mud. :-)
The set up was the problem!! I did it like the link says to, and sure enough the problem is gone. I still feed slow enough that does not overload and keep chips coming out at a steady rate, but they do come out and the hole is clean and no smoke. That was the ticket as well as checking all other suggestions too. Thanks!!
Hey, I have a mortising attachment for my drill press. I have to set the bit with about the clearance of a dime to keep the chisel and bit from over-heating. I also have to make sure that I don't have the chip-ejection slot facing the fence to ensure there's no obstruction.
Usually, I place a dime on the table, and then let two adjacent corners of the mortise chisel rest on the dime while I let the tip of the drill bit touch the table. I square the chisel to the fence, and then tighten everything. Finally, I turn the chuck by hand to verify that there's no metal to metal contact. This has solved my problems with burnt wood. Now, if I could get the mortise located where it belongs ... :>)
Well that is something to try for sure. I will set mine up that way tomorrow and see how it does. I just knew there had to be someone out here that has been down this road before and could offer suggestions, Thanks a ton!! I will try others that come along too if there are any.
I found that setting up a 8mm (5/16") chisel and bit using a one-cent (euro) coin - around 1/16" thick - gave me a lot of jamming problems and eventually a broken auger. Reduced this to around half as much and it cut sweetly.
The other problem I had - with a new Fox 14655 - was when I was making a bed, and mortising in pieces of different widths - ie height when in the mortiser. On wider boards the mortice was off-centre. Having checked that the board wasn't cupped, I discovered that the fence was not at right angles to the bed. Having taken off the two blocks that hold the fence guides to the base I discovered that somebody at the factory had shimmed the blocks! Removing the shims straightened everything out.
I place a cabinet scraper between the chisel and the chisel holder tightener thingy place (sorry for these technical terms) and push the bit up into the chuck (using a piece of scrap wood). I tighten the chuck, then remove the scraper and raise the chisel and tighten it. This leaves a good clearance between the bit and the chisel.
Be sure to clear the bit often: don't try to chop it all at once.
Are the drill flutes getting clogged up? When that happens to me, I back the bit out so the flutes can clear themselves then drill down again. Sometimes, it takes 3-4 times before the hole is drilled.
The bit gets clogged up and ends up burning the wood there, and going at it three or four times was what I have been trying to overcome. I know that likely still will be a problem but hoped to stop some of it. The link shown above helps out a lot with knowing where to set the bit and as soon as I try it I will know if that fixes the problem or not. Hope to try today as soon as I can get to the shop.
pcooper,
A slow feed rate (forcing the chisel into the wood) is essential as well, to allow time for the chips to work their way up the bit's flutes. Remember, you are making the additional wood that the corners of the chisel removes go thru there too; making more chips than a normal drill bit would.
Regards,
Ray Pine
You may try slowing down the feed rate - or slow down your drill motor. Feeding too fast doesn't let the chips clear the flutes and you pack them full. Having the bit in the mortising chisel restricts the flute clearing action, too.
Check the link that Thintz offered. That is the way I set mine ( I just eyeball the gap). If I have a hard time with clogging or cutting I increase the gap, not more than a good 1/8" though. Another thing is the quality of the bit/ chisel set. If the flutes arent deep and well polished then the chips will not travel up them nicely. Unfortunately there is no reasonable way to polish the flutes. My Delta OEM set was mediocre untill I tuned it up. I got a diamond hone for the inside of the chisel, lapped the out side faces then I cleaned up the burrs on the bit itself with a diamond file. There are better brands of chisels out there that don't require all this work, I believe Fishe is a good one. Also sinse you are using a drill press I think that your feed rate might be too slow. You want pretty heavy curly chips comming out. not saw dust.
Mike
The feed rate I had tried to change, and I did understand that there are more chips going in than a regular drilled hole, I really don't think that area is the problem for me, but noteworthy just the same. I tried the last cuts with the bit going the slowest it can, also with gentle pressure and not forcing to go too fast into the wood, and still had some problems, but that was also before the suggestions here, and still haven't made it to the shop to try what I learned from you all in this thread. Anything else you think of and post I will try. Thanks
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