This will only be the second time that I’ve used the old Delta chisel morticer I bought 2nd hand long ago.
The last time I was cutting Mahogony and it cut like butter. It’s been well over a year since then and this time I’m cutting White Oak so I didn’t know what to expect. I had bought the cone shaped diamond hones to sharpen the chisels and they are still really sharp, but I did touch up the boring bit tips with an India slip stone.
I have the machine set up with an X-Y vise and mounted it behind my drill press on a stand made from an old wooden desk with a mobile base, so I can easily pull it out when I use it.
I reviewed the manual and took my time setting up. The oak is really hard and dense, so I set the bit 3/16” below the chisel tips. Even so it took a LOT of downward force to make the first cut, so much so that the lag bolts securing the machine to the softwood riser block pulled out. So I had to remount it with through bolts.
It still took a lot of force, but with the base securely mounted I was able to make good clean cuts. Most of the mortises are all the way through so I cut in from each opposite face making sure to keep the same side referenced against the fixed jaw of the vise. My layout proved accurate as the opposing cuts met with barely any perceptible step.
I was only 0.010” off center and just a pube over 0.5” wide.
About half way through the job I noticed that one of my chisel tips was getting bent, so I dresses the edges with the India stone with the chisel still installed, as I didn’t want to lose my setup.
I used an 1” Aluminum block and a poly shim to set the depth stop for the blind mortises.
And before long I was done making a big mess.
I’m hoping to make the matching ottoman and coffee table next, so I’m going to keep the morticer set up, which will save a lot of time.
-- Matt -- I yam what I yam and that's all what I yam
2 comments so far
stefang
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#1 posted 02-09-2019 11:56 PM
It looks like the mortises came out very nice. I’m a little surprised you had a problem with the chisel as I find that white oak isn’t that difficult to work with. Maybe you need a better quality chisel or a sturdier bevel angle.
-- Mike, an American living in Norway.
Mainiac Matt
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9853 posts in 3379 days
#2 posted 02-10-2019 12:47 AM
The chisels came with the mortiser when I bought it so they’re really nothing special. The cone hones did put a very shallow angle on them, however. So the tips are rather fragile. But the flip side of that is that they are wicked sharp.
-- Matt -- I yam what I yam and that's all what I yam
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