Jet Hollow Chisel Mortiser problem

[Rob Littleton]

Why am I getting round edges on my square holes? Not only that, but the round edges are bigger than the square holes.........

SIGH!!!!!

Anyone know?

[Jerry Olexa]

Rob is this a fairly new Jet mortiser?? Sounds like a bad set of bits or poss heavily used? Give a little more detail and maybe we can help...I have same mortiser and it works fine...

[Russ Massery]

Sounds like you have the bit too far below the chisel.

[Jim Becker]

Sounds like you have the bit too far below the chisel.

Agree...and it's wandering. 1/8" (about the thickness of a nickel) or just a little more is sufficient exposure of the bit.

[Steve Clardy]

I set my jet with a dime as a spacer.
Any more, and the bit wobbles in the shank too much

[Rob Littleton]

This is a new tool. I am using the bits that come with the tool too (so I suspect they aint the best quality).

Anyways, I have heard people say that they set their machines using nickels or dimes, but dont quite understand what that means.

If I install the drill piece and then move the chisel down, I get a mighty squeak. Where are the "nickel" and "dime" measurements taken from and where do you use the coins.

Sorry if this seems a crazy question.

Thanks for your help though

[Kent Fitzgerald]

Where are the "nickel" and "dime" measurements taken from and where do you use the coins.

Here's the routine:

1. Insert the square chisel in its collet. Use a dime as a spacer between the shoulder of the chisel and the collet (i.e., so the chisel doesn't seat all the way in). Don't worry about squaring the chisel to the fence yet. Tighten the chisel set screw.

2. Insert the drill bit in the chuck. Using a piece of scrap, push the bit as far up as it will go and tighten the drill chuck.

3. Remove the dime (it probably already fell out), loosen the set screw, and slide the chisel up. This leaves a dime-thickness gap between the bit and the chisel.

4. Square the chisel to the fence and tighten the setscrew.

It is normal for thr bit to squeak when running idle. It should quiet down under load.

[Tom Hintz]

Rob,
See the link below for a story about setting up a motriser. It has photos of the procedure that will make it more clear. Once you see it, its simple.

http://www.newwoodworker.com/setupmort.html

[Rob Littleton]

Now I get it.........thanks to you guys.

I'm gonna try this tomorrow and see what I can do.

'ppreciate the help. U guys rock.

[Rob Littleton]

GOT IT!!!

Thanks guys. Still a very slight round edge on 2 sides but not half as bad as it was. I will continue to adjust but I am on the right track.

Thanks again.

[Norman Hitt]

Here's the routine:

1. Insert the square chisel in its collet. Use a dime as a spacer between the shoulder of the chisel and the collet (i.e., so the chisel doesn't seat all the way in). Don't worry about squaring the chisel to the fence yet. Tighten the chisel set screw.

2. Insert the drill bit in the chuck. Using a piece of scrap, push the bit as far up as it will go and tighten the drill chuck.

3. Remove the dime (it probably already fell out), loosen the set screw, and slide the chisel up. This leaves a dime-thickness gap between the bit and the chisel.

4. Square the chisel to the fence and tighten the setscrew.

It is normal for the bit to squeak when running idle. It should quiet down under load.

Kent, you should take up "Tech Writing", as that is the Simplest, Clearest and Most Concise explanation of that procedure that I have ever seen, and it is Right On Target. Good Work.;)

[Vaughn McMillan]

Kent, you should take up "Tech Writing", as that is the Simplest, Clearest and Most Concise explanation of that procedure that I have ever seen, and it is Right On Target. Good Work.;)
I agree wholeheartedly (and I'm a tech writer). It answered some questions I've had about my relatively new Shop Fox mortiser. I've been setting the bit about right (but not as easily as using a coin) and getting good results, but I'm glad to hear a bit of squeaking is normal. Thanks Kent. ;)

- Vaughn