Delta Mortiser question

[Geoff Potter]

Picked up a Delta mortiser (used) today. Works great but I am wondering why bit seems to squeal even when not under load. Bad bit or something with the machine?

[Steve Clardy]

I have a Jet. Close to the same as the Delta.

My bits squeal too. I just try not to let it run very long between punching holes. Nature of the beast I think. Metal to metal contact.

[Leo Graywacz]

Waxing the bit helps for a while. Like Steve said, nature of the beast. I nicknamed mie the pull and squeal.

[John Thompson]

[quote=Geoff Potter;747344]Picked up a Delta mortiser (used) today. Works great but I am wondering why bit seems to squeal even when not under load. Bad bit or something with the machine?[/quote

The chisels that come stock with bench mortisers are well.. not exactly candidates for the Machinist Hall of Fame. Not great tolerances and if you look closely you will see some pretty heavy machine marks.

So what you hear "squealing" is metal to metal contact. And that could be caused by several things. First... make absolutely sure your bit is centered properly in the chuck. Make sure you have squared the chisel to the fence before securing it in the ready position.

Now.. make sure you seat the leading business end of the drill slightly forward of the chisel tip. That is your most likely candidate that's causing the squealing. You also need to go back and hone the chisels outside and inside. The inside can be done with cone abrasives.. Again.. the factory tolerances aren't good on those cheap chisels. You have to pick up where they left off and rest assured on a $30 set of chisels, they left early for the day. :)

And BTW.. if you set the drill bit forward to insure clearance, you will find that you have a round hole slightly lower than the squared bottom of the bit. Don't panic.. it will give a nice pocket for glue and nobody will ever see it but you before you insert a tenon. Just us with mortise machines little secret. ha.. ha...

Regards...

Sarge..

[Norman Pyles]

My HF does the same thing.

[Scott Vigder]

My General squeals a bit when not under load. I put a dab of wax on the bit and it takes care of the noise for a few plunges.

I got into the habit of turning off the machine as much as possible i.e. don't let it run when switching form one workpiece to another.

[George Bregar]

As has been mentioned, the drill should be proud of the chisel. I use the "dime" method, and a nickel for 1/2". Squeal also occurs when you get a chip stuck in the chisel.