I was pulling some mortises last night, noticing the pull stroke action required more and more force. Then I noticed that the (gib?) 1/8″x1/2″x10″ shim in the dovetail way was sliding out. if the head was tight in the ways, does that happen when you neglect to grease the ways?
I don’t have a manual, as I bought it ‘scratch & dent’. Even if I grease it, how do I get it to stay in position? is there some dimple (detent) in the shim that binds on the set screws?
Thanks!
mike in olympia
Replies
Mike,
On some mortisers the gib will have small hollows milled into it to accept the tips of the adjusting screws, although many import machines will just depend on the tips of the screws digging into the soft brass to hold the gib in place. If the screws were a bit loose and there was added friction from dirt and lack of lubrication, it is possible that the gib would be dragged out of position.
The fix would be to back off the adjusting screws and drop out the gib to clean it off and to remove any burrs on it with a file. At the same time you can clean off the faces of the dovetail ways.
If the gib has hollows milled into it on one side, and set screw marks on the opposite face, then the hollows are meant to go against the post side of the dovetail rather than to serve as pockets for the tips of the adjusting screws. The milled hollows, in this case, are meant to prevent the pressure from the tip of the adjusting screw from creating a small high spot in the sliding face of the gib that would eventually wear a groove into the relatively soft cast iron dovetail surface of the column.
Usually the gib is installed with one end of it flush with one end of the casting, typically the bottom edge. You can figure out the correct orientation by holding the gib up to the casting along the edge with the adjusting screws and noting the orientation that lines up the screw marks in the gib and/or the pressure relief hollows with the heads of the adjusting screws and one end of the casting. If there are no milled indents for the adjusting screws you can drill shallow dimples in the gib with the tip of a twist drill to create them.
John W.
Edited 10/15/2003 6:00:38 PM ET by JohnW
Thanks John!
that looks like very complete advice, I'll work through it this weekend.
Sometimes I wish I would have persued a slot mortiser instead - and maybe someday I'll trade up. I should probably start a new thread, but just wanted to ask if you knew what decent set up might cost, or recommend a mfg? Do you know if it's a good replacement to cutting tenons on the table saw as well?
regards,
mike in olympia.
Thre is a guy from Rochester NY who is on ebay, always, selling solid rods from 1/2" to 2 or 3" dia., with linear bearings, far discounted from retail. I think they are Thompson rod and bearing sets. I was thinking that these would be the start of a slot mortiser, but am no machinist, so would need a plan. email me if you can't find him as I have his #. He is a retired inventor/ machinist, and interesting to speak with.
Alan
hmm, interesting s4s...
I was also just musing over my PM719 in metamorphisis ~ what if you could put a bearing up in the spot that the chisel bushing goes? It would fit the shaft of a long, say 3/8" x 6" end mill. the new bearing would soak up the lateral stress during bed movement that the mortising motor would not be suitable for? You kinda see what I'm getting at? Getting the new bearing to be concentric with the drill chuck on the mortise motor might be too difficult... and the motor speed's probably too slow...
just a thought.
mike.
oh, heck, I meant to ask what a linear bearing was... is that for the bed movement or the cutter?
thanks,
mike in oly
Edited 10/16/2003 7:38:16 PM ET by MIKECREAMER
Mike,
Most if not all of the slot mortisers seem to be made in Europe these days and are most commonly seen mounted on the sides of combination woodworking machines, but they are available as free standing units. I think the cost starts at a around a thousand and goes up from there. A search might turn up a nice used machine at a good price.
Slot mortisers are usually used with loose tenons, that is a slot is cut into both pieces to be joined and a separate piece of tenon stock with rounded edges is used to join the two pieces, it's a very efficient way to make a sturdy joint.
John W.
Hi John,
yup, I've seen the Robland video where the guy builds a loose tenon door. (I even looked at that x31 at the woodworkers show several years ago - man, a lot of uglyness close up, lol) Anyway, guess I was thinking that if you can use a router to make tenons, like the new Leigh set or similar home-made versions, wood rat, etc, surely you could do it on a slot mortiser as well?
guess I out to get some work done today! I've been running my mouth a little...
mike.
Mike, give a call to the Jet/Powermatic folks. They'll send you an owner's manual. You buy it at the outlet down near the Jet warehouse? That's where I got my jointer, good deal!
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Good idea Forestgirl, and sorry if I was a bit sarcastic with you before ;-)
Yea, the auburn outlet is a good place to spend $! I also hope to make it to the woodworking show at the T-dome this weekend - to google over some slot mortise machine, if someone brings one.
regards,
mike in oly.
I'm still on the fence about Tacoma -- wanted to go but have zeeeeerrrrrooooo $$ so would be going down just to drool and socialize with the WWA guys at lunch. Mortisers, eh? I'd love to see the new, upgraded Delta mortiser side-by-side with the Shop Fox, which has been my front-runner until recently. If you see 'em, let us know what you think!
PS: That place in Auburn is dangerous! I'm glad I'm across the water, and well out of range. That's where I'll go, though, if ever in the market for a PM66.
forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Edited 10/16/2003 6:00:53 PM ET by forestgirl
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