Delta Mortise Machine Chisels

[Sean Troy]

I have a Delta Mortise Machine and the four chisels that came with it. I bought it new about 6 years ago or so. It hasn't seen a whole lot of work but I get the feeling using it, the chisels are not near as sharp as they could be. Should I just sharpen the chisels with a cone? Could it be the bits? Should I just replace the chisels with new because Delta Chisels are garbage? Any help would be appreciated. Thanks, Sean

[Rick Potter]

I have some nice ones...made in Germany, I believe. I also have some not so nice ones, made in Taiwan. All Delta.

Sharpen them. What do you have to lose?

[Sean Troy]

I have some nice ones...made in Germany, I believe. I also have some not so nice ones, made in Taiwan. All Delta.

Sharpen them. What do you have to lose?
I guess I've got nothing to loose. I need to purchase a cone to sharpen with for these or new ones anyway. Thanks, Sean

[Mike Cutler]

Sean

Sharpen and hone the chisels. Use the cone on the inside and a honing stone on the outside. Ensure that the leading edge of the drill bit is also sharp. The flutes may need a little light dressing, very light.

Those chisels will do a better job than you may have been led to believe, once you get them sharpened up. They're not Clico's. but they are very capable of performing decent work.

[Ken Fitzgerald]

Sean,

I have a General International mortiser and initially I wasn't very happy with it's results. Then I bought the following two sharpening tools http://www.woodcraft.com/product/144385/mortise-chisel-sharpening-kit.aspx and http://www.rockler.com/3-piece-mortise-chisel-sharpening-set . I use the kit from Woodcraft to cut a new edge on the mortiser chisel and the kit from Rockler to diamond hone it.

I also sharpen the cutting edge of the bit with a jewelers file.

It is also important to flatten/hone the 4 sides of the mortiser chisel!

The results made using my mortiser a enjoyable snap.

[Sean Troy]

Sean

Sharpen and hone the chisels. Use the cone on the inside and a honing stone on the outside. Ensure that the leading edge of the drill bit is also sharp. The flutes may need a little light dressing, very light.

Those chisels will do a better job than you may have been led to believe, once you get them sharpened up. They're not Clico's. but they are very capable of performing decent work.

What would be best used to sharpen the leading edge of the bit? Thanks, Sean

[Sean Troy]

Should I flatten/hone the 4 sides as I would the back side of a bench chisel ?

[Ken Fitzgerald]

Sean...that's what I do. I hone all 4 sides. It's the last thing I do.

[Stan Calow]

I gave up on the chisels that came with my Delta. I thought the bits were just not right.

[Sean Troy]

Sean...that's what I do. I hone all 4 sides. It's the last thing I do.
Thank you Ken

[Howard Acheson]

There are two steps to sharpening a mortising chisel. The first is to use a cone shaped grinding bit the sharpens the inside of the bit. The second step is to carefully hone the outside surfaces until they are as smooth and shiny as you would get the backs of your hand chaises or plane blades. I used my wet stones for this step. This step allows the chisel to more easily enter the wood and produce a clean edged mortise.

[Howard Acheson]

I meant to add to my above posting that my Delta chisels and bits are 25+ years old. I don't use them a lot but they have remained in excellent shape.

[Mike Cutler]

Should I flatten/hone the 4 sides as I would the back side of a bench chisel ?

Sean
Yes all four side of the mortise chisel need to be honed liked the back of a chisel. Don't go crazy though. Hone the inside first and then the outside. Just like removing the burr from a chisel. Those four chisel corner points should be extremely sharp. Essentially you are making corner chisels.
The drill bit makes contact first, then the chisel takes over. The drill bit is then clearing waste, and staying just ahead of the chisel.

[vince dale]

I used this method on my chisels and they are a pleasure to use again. You can get replacement chisels and cone sharpeners from lee valley

http://www.finewoodworking.com/tool-guide/video/sharpening-hollow-chisel-mortising-bits.aspx

[roger wiegand]

Sharpening, as described above, makes a huge difference in the performance of these machines. The one's that came with my General were very rough, it took a lot of work to get them into shape and there were still imperfections in the metal that give rise to ragged edges. The good ones from Lee Valley started off dramatically better and only took a little work to polish up. I don't know yet whether they stay sharp longer.