HF Mortise bit chatter & vibration noise

[Uncle Hook]

I recently purchased the Harbor Freight Mortise machine. The motor runs smoothly when the mortize bit is not installed.

I get bit vibration, chatter, and a bothersome noise when running the machine with the mostise bits installed. The noise is worse with the larger bits. Lowering the bit below the chisel does not eliminate the problem.

I have no prior experience with mortise machines and I am interested in hearing from others about their experiences.

Is bit vibration, chatter and noise normal with mortise machines?

Any suggestions for determining whether the problem lies with the bits or whether the machine is at fault?

Any suggestions for things to try, beyond bit lubrication which does not seem to help?


I have until the end of the week to return the machine for a refund.

[LCHIEN]

probably the mortising bit is not well centered in the chisel. This causes a lot of rubbing and vibration as the bit repeatedly hits the inside walls of the chisel.

There should be some minor adjustability by how the chisel is fastened to the supporting arch mechanism. The bushing may be cocked for example (not parallel to the chuck and bit) or maybe not centered under the bit.

Check the bit alone (no chisel) in the chuck, see if there is a lot of runout or bit wobble.

If you can't correct it, you'll have to take it back, I would think.

[eddy merckx]

I get a little bit of high pitched scraping noise while I'm running my HF mortiser. I doesn't affect performance, so I assumed it was normal. Maybe the higher end chisels offer a better fit. I did file out the inside of my chisels to eliminate the machining marks and allow an easier path for the chips.

Eddy

[Uncle Hook]

Everyone - Thanks for your replies.

I returned the mortiser to Harbor Freight after checking the runout using a high speed steel bit. Did not know what else to use.

I used the Harbor Freight dial indicator and found a difference of 17 indicator ticks in total runout between the opposite sides of the bit.

[LCHIEN]

Everyone - Thanks for your replies.

I returned the mortiser to Harbor Freight after checking the runout using a high speed steel bit. Did not know what else to use.

I used the Harbor Freight dial indicator and found a difference of 17 indicator ticks in total runout between the opposite sides of the bit.

I'm pretty sure that would explain it.