Hollow Chisel Mortiser Table Modification

[Kris Cook]

I have a Jet bench-top mortiser. It works fine but the clamping system leaves a little to be desired. I have been wondering if I could modify the table with some kind of retrofit x-y table. I have seen some of the x-y vises that are available for milling applications. I haven't found one that doesn't take up a lot of the vertical travel available (raises the work piece too high).

Has anyone done this kind of modification? Any idea where to look for a table/clamp that might work?

Thank you,

[Tom Trees]

Here is a recent youtube video on the subject.
I found it an enjoyable watch
nqItaZA_LqE
I can't seem to post videos, so here's a link instead...
https://www.youtube.com/watch?v=nqItaZA_LqE

Tom

[Kris Cook]

Hmmm. Yes, interesting to watch, and impressive fab skills for sure. Probably not going to go to those kind of extremes. If I can't find something that is readily adaptable I may try to brainstorm some kind of homemade solution. Or, just buy something that has the functionality built in. :cool:

Thanks for posting the video.

[Jay Kepley]

I just skimmed through the Youtube video. That's an extreme option! Here are a couple of thoughts on a more modest level. I own a Jet benchtop mortiser. I haven't used it much, but I'm working now to figure out how best to use it. The hold down works generally well. I put the hold down close enough to hold the piece I'm mortising, but not too close to cause it to not slide when I want to slide the piece. I usually use a doubled over piece of paper to set the hold down. That's worked well. I also clamp the piece using a track saw type clamp that is easy and quick to use. That keeps the piece from moving when I'm cutting the mortise, and it only takes a quarter turn to slide the piece and a quarter turn to tighten again. I also turn the chisel ejection side to the right, allowing good dust collection simply by holding a shop vac hose within an inch of the mortise with a bungee cord. That allows for better visibility and probably reduces heat (but that's a guess). I start on end of the mortise I want, then go to the opposite end, then the middle, then fill in to complete the mortise. This approach allows for easy mortising and seems to minimize flexing of the chisel. I haven't done this yet, but if I need a mortise wider than my chisel, I going to try a shim between the piece I'm mortising and the fence (instead of trying to move the fence in some precise way, which might be difficult with this machine). Please let me know if these doesn't make sense. I'm still trying to figure out how I can best use this machine. One last thought: I ordered a bit and chisel from Lee Valley, and it was a lot nicer than the OEM Jet bit and chisel set (no surprise there). Good luck!

[Kris Cook]

Jay - thank you for your input.

I have used mine a fair bit to date, and for my needs the stock chisels seem fine. I did get the conical sharpeners from LV to tune the chisels up. There was a pretty good article in (I think) FWW on tuning up the chisels and bits. I think it was written by Bob Van Dyke.

I generally turn the chisel opening to one side and work away from it - this gives the chips a place to go, and minimizes binding and heating.

I may try to come up with some kind of lead-screw that will move material on the "x" axis, which would speed things up a bit. The front-to-back ("y" axis) adjustment is a bit kludgy and generally moves when you tighten the fence clamp. A shim strip of some kind as you mention would certainly help.

[Brian Holcombe]

Every once in a while I see an old mortiser up for sale and they’re usually pretty cheap, less than what it cost me to modify my Felder. :D

[Kris Cook]

Brian - if you haven't looked at the video above you should check it out. Maybe a little coarser than your approach to modifications but impressive nonetheless. Also - was nice to see your work in FWW - congrats.

[Brian Holcombe]

Thanks Kris!

It's a neat modification, looks very much purpose built.

The trouble with the bed area is that the table and ways need resistance against bending, so easy things like linear bearings are out (IMO). You'd be in the territory of boxed ways since they can be made in a way which supports against bending forces being applied by the chisel.

https://wiki.opensourceecology.org/wiki/File:Xyboxed.png

You'd also need a screw assembly to position the table and locks to keep it in place.

[Jared Sankovich]

Or, just buy something that has the functionality built in. :cool:


That would be my vote.. i was in a similar situation. while i have the machines to modify the stock jet and add a table, rarely is it worth the time and effort.

In my case i just bought a bigger mortiser with all the capability id ever want. All things considered not that expensive and a lot faster.

403656

[Kris Cook]

Jared - yes a machine like that would be the ticket. I will keep my eyes open.

Thanks

[Kris Cook]

Brian - that looks like a slippery slope and maybe not worth the effort for this machine.

Guess I will use what I have and keep an eye out for something else.

Thanks