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Hi,
I’ve looked and to date have not found the right answer to the question of how to quickly and accurately cut mortise and tenon joints. I don’t yet have a mortising machine (this may drive me there), and hand cut is way too slow, the multi-router is way too expensive and looks like it would take a long time to set up, so I’m down to the good ol’ plunge router.
I want to set up quickly, accurately, and repeatably. I want to be able to put a mortise near the end of a board (where the router or guide starts to fall off the end). I’d like the joint to fit without any hand tuning. During the cut, the router needs a wide base of support, even when putting a mortise in the edge of a narrow board. I want to minimize the hand cutting required to square up the ends of the mortise. I have a strong preference for fixtures that ‘self-align’ – no fine tuning desired. And I would like a $10,000 gift certificate for tools for Christmas!!
I’ve built a couple of fixtures and conceived of several more, but all have some shortcoming or another (yeah, they work, but it takes me too long to get the job done). I figure, right here in River City, is about the best set of resources in the world, so help me out. How do you folks cut them?
Thanks,
Frank
Replies
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If you're not tooled for production, mortises and tenons are a time consuming chore. I tend to want to work fast, but in this case, it's all Zen. I use a Delta tenoning jig and a mortiser. It's slow and it takes a lot of patience to get it right. I now prefer to use the tenoning jig for both 1/2 of the joint. It's an exposed joint, but it works well for most applications; glued and clamped, it'll never go anywhere.
fv
*I forgot, watch that fluorescent fixture above your table saw!fv
*Frank, Have you considered using loose tenon joinery (sometimes called floating tenon)? This procedure involves cutting mortises with a plunge router in both members and gluing in a tenon to join them. It's sort of like doweling, but using elongated slots instead of round holes. You should be able to find out more info if you search the index. When I use this procedure, I use a mortising jig called "Mr. Mortise". This provides a stable base for the router which helps overcome the problem you mentioned of trying to balance the router on narrow edges. It used to be marketed by Ken Picou, but haven't seen it advertised lately. In case he is no longer in business, it would be a very simple jig to make. GPW
*I chain drill some holes to the proper depth, using a drill bit the size of my mortise. I use a dowel guide to keep the holes straight. I square up the mortise with chisels.
*Frank:What ever type jig that you build,put a small spacer at each end of the mortise guide slot to hold the jig slightly up off the work piece.This gives a space for the chips to be ejected from the cut.Otherwise you must constantly be removing chips that clog up the guide slot and get in the way of the guide bushing.PAT
*No one has mentioned a router table. I found it to be much quicker set up. Although I prefer to use my drill press and square them up by hand (I dont do this as a business)...I used the router table to cut the 60 mortises for the spindles in a Stickley Morris chair. You do have to round off your tenons or lengthen the mortises using the router table.
*My router table leaves much to be desired.Some day I may build one with all the bells and whistles.Now I have more control if the work and jig is clamped in the vise so that I can more easily see what I am doing.I do use the table for mouldings and edges where stop cuts are not required.Our Saturday friends,the Rosenthals,on P.B.S can tell you most anything you need to know about routers and fixtures.Find them at http://www.routerworkshop.com PAT
*Have you seen Pat Warner's book: Fast, Easy, and Accurate Router Jigs? His mortise jig might be what you want. Check http://www.patwarner.com/
*Major,I have that problem on my mortiser you described: clogged bits.Would you run your solution one more time w/ a bit more detail.Just what do you mean by slotting "guide"? I appreciate your suggestion...Jose
*JOSE: my description was meant to apply to the use of a plunge router for the mortises Sorry for the confusion.For my hollow chisel setup, I have found that the bit and chisel need to be sharp and smoothly polished.Especially on soft wood,a touch of candle wax on the tip of the bit,makes the shedding of the chips much easier.If you are cutting a deep mortise the sides may be keeping the chips in the chisel.In this case,rotate the chisel so that the chips are discharged into the mortise instead of against the sides.PAT
*Frank,Since you asked I cut mine on a Delta 12" drill press with the Delta mortising attachment, takes me very little time in terms of set up and practacally no clean up of the mortise is required. Dano
*Slot mortiser...laguna/robland or even cheaper build the one with drawer slides as seen in FWW a few issues ago.
*My solution for speed is holding the workpiece in a two way vice bolted to the drill press table. When positioned side to side, lock that travel and of course the table. Then it just happens that each turn of the other crank moves the workpiece 1/4", with the depth set it becomes a two handed operation - one on the vice crank and one on the drill press. Time elapsed for a 3" mortise is lest than two minutes. Don
*Some key information is left out of your post. Are you using a router cutter to make the slot or just drilling a progession of holes. Any chuck that is just held on using a jacobs taper or morse taper will come loose with lateral pressure. Some drill presses use a threaded locking ring to hold the chuck on and that's the only kind I would put lateral pressure on. The thought of a high speed chuck and cutter bit coming loose gives me the shivers.
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