I bought a general mortiser. It works great. I sharpened the bit and the chisel. It works fine starting out. After chopping some mortises the bit starts to rub against the chisel and makes an unbearable grinding noise. I then take the whole setup out and grind the inside of the chisel. The problem is solved but then it happens again and again. I know I am not doing something right. I have tried changing the chisel depth too. I have the general chisel set. Do I need to get a better set of chisels or what is the problem here. I really appreciate any help.
Replies
You probably don't have enough gap between the bit and the chisel. Try lowering the bit by 1/32 to 3/64th and firmly tighten the chuck so that it doesn't slip.
The augur is rising up into the chuck- find out why.Or (less likely) the chisel is being pulled down onto to the augur when you withdraw.
There should be plenty of clearance between the tips of the chisel and the shoulders of the augur ie it must drill before the hollow square chisel can do its work.
Another cause could be that the augur is being distorted under load and becomes bent- cheap chisel sets do that.
And the machine is only as good as the chisel and bit set- it pays to have a good quality one.Philip Marcou
Edited 8/30/2006 9:57 pm by philip
Mine screeches too. I set it correctly but untill I start cutting there is steel on steel in the chisel. I suspect it is that the bits aren't very good (Delta OEM). But it has never caused a problem.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
Mike, if the screech is due to the sides of the augur rubbing the walls of the chisel there is no problem: you can get rid of it byapplying some fine grinding paste to smooth out any rough spots. When in use if you let it eat some candle or similar wax that helps. But the shoulders of the augur should never be contacting the edges of the hollow square chisel-that is the kiss of death.Philip Marcou
Stein, do you mean that General Machines of Canada, them that made that lathe and some other items like the thicknesser etc have gone to the dogs as well?
Sorry, not General of Canada
I'm not sure you will ever get rid of all the noises a mortiser makes but I do have a story at the link below that shows the process for setting the bit/chisel to establish a good gap that helps insure a path for the chips and lets the drill do its work ahead of the chisel, as it is supposed to.
http://www.newwoodworker.com/setupmort.html
Tom Hintz
Because there is always more to learn!
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