Experience with new Delta Mortiser

[Ken Weaver]

Ken,

Very nice pictures and good tutorial. I have the Jet mortiser. I have cut the mortises like you suggest but I do not anymore. I do not enjoy that first cut and have found I can get straight sided cuts without several plunge cuts and then clean out cuts. I just do the one 4 sided plunge cut and then go to the other end. I have also gotten to where I can slide the material down the fence and get a square sided cut consistently (at least the last few I did were fine). It is safer to clamp, like you recommend, however. I have also messed up doing the cuts without clamping. Fortunately messing up in this case is a slightly oversized mortise which will work but there is a loss of strength.

My mortiser is mounted lower than my workbench, it looks like yours may be higher. Lower allows me to get more leverage for 1/2 mortises in hardwood, my handle does not adjust.

Do you mortise deeper than the tenon will be long so you do not have to clean up the bottom with a chisel or do you clean it up? I used to go over-deep but have started cleaning up in recent projects. It doesn't take that long and seems like a better way to do it. On the other hand, who but me would know?

Jim

Thanks for looking Jim. You're right, the first cut is the hardest, so far I do each end and then split the difference, what's left usually come right out as in the picture. I May change the technique as I get more comfortable with it, right now I'm still a little intimidated by it. So far anything off has been within the shoulder clearance of the tenon stock. Mine is set higher which seems to give the best leverage for my bursitis. Right now I go just slightly deeper to give room for the glue, I still clean out each mortise tho.

[Jeffrey Schronce]

Well DOHH! Helps if you put in all the parts! Will have to change the tutorial tomorrow. Am glad it wasn't something important like the chisel or bit.

Well so much for your stinking tutorial! I thought you said the manual was good! LOL!
Just busting your chops a little. Glad you got it staightend out. Your good deed of documenting using this machine in the tutorial was rewarded by pointing out a fix for a problem you were having. Karma.

[davidtu]

Thanks for the info Ken!

Is there general consensus on one of Ken's suggestions regarding spacing out consecutive cuts? The Delta manual incidates one should move cut by cut adjacently to allow the chips to come out the open side of the chisel (assuming of course you are moving "away" from that side).

[Ken Weaver]

Thanks for the info Ken!

Is there general consensus on one of Ken's suggestions regarding spacing out consecutive cuts? The Delta manual incidates one should move cut by cut adjacently to allow the chips to come out the open side of the chisel (assuming of course you are moving "away" from that side).

Not sure - I've seen other sources that recommend what I did on the rationale that eating away down the line may deflect the chisel sideways. I plan on trying Jim's method next time and see how it feels. Either way the key thing is to keep the chisel and bit clear. As long as you do that, it may only be a matter of preference of personal preference.

[MBG]

Ken,

I just do the one 4 sided plunge cut and then go to the other end. I have also gotten to where I can slide the material down the fence and get a square sided cut consistently (at least the last few I did were fine).
Jim

Jim - can you explain your technique a little better for me - not getting a good visual on "one 4 sided plunge."

Ken - nice tutorial!

Just made one good mortiser out of two broken ones I got from Amazon (first had a crack in the top motor mount casting - second had a broken fence). After setting up the tool I made a couple of test cuts (1/2" bit) in a piece of oak. The first two cuts had a little burning and I had to use more force than expected. I then re-set the drill bit to protrude a little further and made another two cuts and it cut the easiest of all, but, then I made a third cut at this setting and got smoke and chips caused smoke and the bit to stall.

How far do you guys protrude the bit beyond the chisel?

Is the chisel dull?

Do you try to make cuts with one stroke or pull the bit in/out of the hole?


Thanks,

Mike

[Jeffrey Schronce]

A little more on bit and chisel set up per FWW :

Insert the bit and chisel, and tighten the chisel.
Place a piece of scrapwood on the table of the mortiser, then slip the bit into the chisel. WIth the tip of the bit supported by the scrap, slip the shank of the chisel into the mounting bushing, then tighten the shank to allow about 1/8" space between the shank and the bushing. To help wood chips eject as easily as possiable when you're cuttin a mortise, position the slot of the chisel so that it faces either left or right.

Reposition the bit and reposition the chisel.
Use the lever arm to lower the chisel until it just touches the scrap. Tighten the bit in place. Lossen the chisel and push it up until the shank butts against the bushing. Theis positions the end of the bit 1/8" below the chisels end. Place the crap againste the fence and slide the fence until the scrap butts against the chisel. hold the chisel, loosen the setscrew and rotate the shisel until one face is parallel to the scrap.

[Ken Weaver]

Just made one good mortiser out of two broken ones I got from Amazon (first had a crack in the top motor mount casting - second had a broken fence). After setting up the tool I made a couple of test cuts (1/2" bit) in a piece of oak. The first two cuts had a little burning and I had to use more force than expected. I then re-set the drill bit to protrude a little further and made another two cuts and it cut the easiest of all, but, then I made a third cut at this setting and got smoke and chips caused smoke and the bit to stall.

How far do you guys protrude the bit beyond the chisel?

Is the chisel dull?

Do you try to make cuts with one stroke or pull the bit in/out of the hole?


Thanks,

Mike

Mike -
Don't have the manual with me but I believe they recommend 1/8 - 1/16". It could be that the chisel is dull and you should dress it.

I also found that if I took smaller bites, i.e. lifiting the bit quite frequently, it helped the bit to clear itself. Be sure that you face the slot in the chisel to one side so the cuttings can clear from the bit. Every time I tried to go all the way in a single stroke (at least in oak) I got burning. It may be different with a softer wood, its part of getting to know the machine. The difference in the force is quite obvious and is startling at first, but once you get the feel for it its not as troublesome.

HTH -