Thread: Hollow chisel morticer bits

Inside they can be sharpened with a cone shaped die grinder/dremel bit, outside can be done on a stone.
They dont need much sharpening to be sharp, dont go to far as you'll shorten the life of the chisel.
You can sharpen the auger bit too with a file, generally they are not sharp to start with I did mine and got a surprise how much better it worked...

Oh and remember to allow plenty of height clearance between the bit and chisel, bout 1~1.5mm for dry hardwood and 2~2.5 for pine etc etc.

Originally Posted by Harry72

Inside they can be sharpened with a cone shaped die grinder/dremel bit, outside can be done on a stone.
They dont need much sharpening to be sharp, dont go to far as you'll shorten the life of the chisel.
You can sharpen the auger bit too with a file, generally they are not sharp to start with I did mine and got a surprise how much better it worked...

Oh and remember to allow plenty of height clearance between the bit and chisel, bout 1~1.5mm for dry hardwood and 2~2.5 for pine etc etc.

Harry - thanks very much for that
I didn't think to sharpen the auger as well. . .
Thanks for the tip about clearance - says in the onstriction boyk to hallo 1 - 16mm clarence bitwin sharp chesil and bit piont
(I took it to mean 1 - 1.6mm)
I'll try the 2 - 2,5 clearance
Thanks again
Jedo

Use a 5c or 10c piece as a clearance gauge, put the tip of the bit on a piece of timber (while in the chuck) slide the coin across and drop (gently) the square bit onto the coin, tighten up and retract and reclaim your coin.

I did this at school.As the cherubs had made a mess of the chisel and they were going to buy new one s any way.

I found a tapered mounted stone, the type which hardware shops sometimes carry as a mixed set.

I put the stone in one of our lathes and pinched the fitters diamond for truing the grinding wheel. Held the diamond tool in the tool post and tapered the mounted stone to the same taper angle as the chisel center.

Placed reshaped stone in bench drill chuck a ground inside of chisel until sharp. I filed the bit cutting edge. It worked for a good while until the cherubs turned it blue by mis adjusting it.

It may work for you
Grahame

Originally Posted by Iain

Use a 5c or 10c piece as a clearance gauge, put the tip of the bit on a piece of timber (while in the chuck) slide the coin across and drop (gently) the square bit onto the coin, tighten up and retract and reclaim your coin.

Hi Iain
Hmmm - sounds easier than my way. . .
I been mounting the auger in the chuck then lowering the chisel and putting a 5c between the shoulder of the chisel and the housing - tighteneing the housing screw and removing the 5c
You way sounds easier
Thanks
Jedo

Originally Posted by Grahame Collins

I did this at school.As the cherubs had made a mess of the chisel and they were going to buy new one s any way.

I found a tapered mounted stone, the type which hardware shops sometimes carry as a mixed set.

I put the stone in one of our lathes and pinched the fitters diamond for truing the grinding wheel. Held the diamond tool in the tool post and tapered the mounted stone to the same taper angle as the chisel center.

Placed reshaped stone in bench drill chuck a ground inside of chisel until sharp. I filed the bit cutting edge. It worked for a good while until the cherubs turned it blue by mis adjusting it.

It may work for you
Grahame

Hi Grahame
Well - dun havva lathe. . .
Read about doing the same kinda thing using a drill press though. . .
Shaping tapered stones to suit each hollow chisel
Then using the re-shaped stone to sharpen each hollow chisel
Up to now - been just using a round pin file - manually "honing" the inside curve, then a rub with a flat file on the outside face to clean up the burr
Seems to make a difference. . .
Thanks a lot
Jedo

AND NEVER OVERTIGHTEN THE QUILL, the buggers break.
(Yes, I was shouting but this part is prone to damage more so than any other part of the setup).

Yep right about the coins... 5c~10c for hardwood and 10c~20c for softwood.
Be careful grinding the center of the chisel if you go to far you will affect the augering action and cause burning from friction of saw dust rubbing. Easy way to tell is on the 1st plunge of your mortice it will smoke and blue the bit/chisel.

Originally Posted by Harry72

Yep right about the coins... 5c~10c for hardwood and 10c~20c for softwood.
Be careful grinding the center of the chisel if you go to far you will affect the augering action and cause burning from friction of saw dust rubbing. Easy way to tell is on the 1st plunge of your mortice it will smoke and blue the bit/chisel.

bit late then Harry - eh?

Yeah I did it to one of mine to start with, it still works slowly and with a bit of smoke, its gradually getting better as am sharpening it every time I use it.
What happens is there is to much clearance which allows the chips to build up, then the bit rubs against it causing it to heat up... and its a double whammy if its resinous wood like pine, the heat melts the resin's making it even more sticky.
Once you've smoothed out the outside of the chisel there's no need to touch it again, just the occasional touch up on the inside and then remove the wire edge.
These chisels do stay sharp for quite some time unless your morticing into very abrasive wood.(or using real cheap chisels/bits)