I bought the Delta benchtop mortiser about a month ago, tried
a few 1/4 inchers and was satisfied that all was ok.
Fast forward. Today I had a real project. Four M&T flat paneled
doors (roughly 72 x 24). Poplar R&S w/1/4 oak ply panels -
paint storage cabinet for the workshop.
Anyhow, I get to mortise #6 on stile #2 and the damn bit snaps.
This is crap for sure & I guess I should have known better than
to expect more when the bit set is 'free' with the machine.
My question is how do the Delta "professional" chisels/bits compare
to this? I would like to get a good set from somewhere, so if someone
could recommend another set, I would appreciate it.
How much gap did you set between the bit and the chisel?
Too much and the bit can move laterally. Tool little and
the bit binds against the inside of the chisel. Either one
can snap a 1/4" bit.
Did you polish the sides of the chisel and sharpen the bit
Were you getting any burning or did you hear any
squealing while making plunge?
Try The Forty Cent Method
Fisch makes pretty good chisel/bit sets.
I was very careful about following Delta's instructions on
the gap - about 1/8 inch as I recall. I don't think this
caused the bit snapping.
No, I didn't do this. I'll try it ob my next set.
No, I didn't have any indication that anything was going
wrong. No burning. I was not forcing the bit in any
way. I was trying to be careful since this was the first
time using the machine 'in production'.
I checked this out. It is similar to a method outlined in
Woodworkers Journal (I think) a month or two back.
I have the same Delta set. I helps to polish the outsides. I used my water
stones. I also bought the conical sharpener from Lee Valley. That helped
also. Then I used a thin file to sharpen the augers. Just follow the angle
and take a half dozen strokes. Do both the bottom cutter and the side
My guess is that there are still better sets out there, but a little work
made big improvements.
I think I figured out what happened. After re-reading some
articles on mortising in Wood magazine, I realized that
I was taking off too little material with each plunge.
I was using the 1/4 inch set - the most vulnerable to stress
when you plunge. The article suggested boring a starter hole
at each end, then take "only slightly overlaping" plunges between
them. Thinking I would "save" the bit, I was plunging
only about half of the chisel width which
causes the drill bit to deflect a bit and probably caused
the stress which snapped it. I could see the chisel deflect
somewhat also. Operator error!
To finish my small project, I dug out my 1/4 bit from my
Grizzly set that I used with my drill press - slipped nicely
into the delta chisel, but I had to hacksaw off about 4 inches.
Since I will probably use the 1/4 and 5/16 chisels the most,
I think that I will upgrade those two sizes.
Thanks for all the help!
I read that article. I've done the same thing thinking I'd get an easier
Making the plunge at each end has a side benefit also. You won't overshoot
the mark is it is covered with chips when you get to it.
Even without snapping, repeated stress like that could ruin the chisel. Cut
evenly whenever possible. Also suggest the FW articles on chisel tuning. In
addition to what's mentioned below, an outside relief in the body cuts down
the friction from plunging. Inside should be cleaned and ejection slot
deburred well, both to allow better chip ejection. I've used several types and
agree with what I'm seeing here, that the Delta (Austrian) work well.
Thanks for the info Gerry
Those seem to be good suggestions. I'll have to search my FW
collection for the article you mentioned.
When you say Delta (Austrian), are those also called
Delta "Professional" (by Amazon/Tool Crib)?
The Delta chisels I bought a couple years ago are from Fisch - got them
at the orange Borg. One has to read the country of origin and look for
Sweden/Holland/Switzerland or somesuch (wherever Fisch are made).
Owen Lowe and his Fly-by-Night Copper Company
Offering a shim for the Porter-Cable 557 type 2 fence design.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.