Hi – I need to mortise 4 table legs. I was going to build one of the mortising jigs described in FWW and use a plunge router. But I thought I could do this on a router table by setting up 2 parallel guides seperated by the width of the leg (to keep the leg from moving side to side), and make some marks on the table to indicate where to stop the mortise. Then I plunge the wood onto the bit and slide the leg forward/backward to create the length of the mortise. So instead of bringing the tool to the wood, I bring the wood to the tool. Has anyone tried this and have some comments? Maybe there is something I am overlooking that will make this either difficult, inaccurate or dangerous. Thx -Yurij
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Replies
It can be done, but it's hard to control the piece you're trying to mortise. The accepted way of mortising using a router is to plunge to full depth at each end of the mortise, and then take lengthwise passes, about 1/8" deep at a time, to clean out between. That's tricky and time consuming to do with the router in a table.
-Steve
Saschafer - Thx, I see. With the plunge technique you get clean ends. With the touer table I need to always lower the piece so that the bit is in the middle and then move to the ends, resulting in uneven ends. It just depends how accurate the stops are. On the flip side, all the chips "fall" right out using the router table, which might be benefit.
Not only do you get uneven ends, but when you cut the entire mortise at full depth, the torque on the workpiece tends to cause it to rotate ever so slightly, causing the axis of the mortise to be misaligned with respect to the axis of the workpiece:
View Image
-Steve
I would think that the 2 fences would be tight enough against the leg to prevent this from happening, while allowing movement along the axis. maybe not.
"I would think that the 2 fences would be tight enough..."
Yes, you would think that, but it's surprising how much flex and slop there really is in a supposedly rigid structure when you stress it.
-Steve
looks like i will be building a mortising jig. too bad. i thought this router table method would work pretty well.
Steve's advice is right-on. I've tried a couple of different "plunging" operations on the table and discovered the hard way that bringing the tool to the stock would have been a better idea, both with regard to the quality of the cut, and to safety.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
Using a quarter-inch up-cut spiral bit, I've occasionally had the bit work loose and climb into the work, when I've tried to take too deep a cut. It's never happened with a 3/8 or larger bit, all of which have 1/2 inch shafts. The damage caused isn't usually visible, but annoying all the same.
Jim
Lowering the work on a live cutter in the router table, tho garden variety suicide, is common. And some folks claim excellent results.
In my view, it's dangerous, inaccurate & overly technique sensitive. So what else is there? Hand routing.
Tho not a triviality (see the link) it works well if you're well fixtured.
Yuri,
The Lee Valley router table can be fitted with a "router jack" - a mechanism that allows you to push the router up from below the table with the bit spinning and the workpiece already flat on the table. It uses a foot-operated pedal so both your hands are still free to move the workpiece back and forth along the fence.
If you use also their end stops (to limit the travel of the workpiece to get the mortise length required) and their hold-downs (to stop the workpiece rotating on the table) you can get good mortises with the "drill both ends then route out between with several passes" method.
I have done this but didn't personally like the router jack as it tended to interfere with other kinds of routing operations I wantd to do. (It is a bit of a fadd to take it on and off and LV assume it will always be left on, as your main router-raising method). However, it does work better than lowering the workpiece on to an already raised bit.
http://www.leevalley.com/wood/page.aspx?c=3&p=43039&cat=1,43000
Lataxe
lataxe - thx for the pointer to this. but i think i'll build one of the simple mortising jigs described in FWW. the simpler the better.
yurij,
I cut mine all the time on the router table, I've never had any twist. I just set the fence and mark a couple of beginning/ending pencil marks on the fence and the stock...take 1/4 deep cuts with 1/4" bit...less if bit is thicker. I do not drop it in the middle and work to each end..that is a mistake. Just move stock down over cutter on left end and move stock to the left slowly.
BG - So you feed it so the cutter will pull the leg toward a single fence. That should keep it aligned. Do you use a spiral bit? The nice thing about the table method is that I can set the height of the bit 1x, then route all 8 mortices, then bump up the height and do it agin, etc... good to hear you had success with it. Any advice on lowering the leg onto the bit? i.e. putting the mark somewhere so its exact? I will have to try it on some scrap. thx -Yurij
Yurij,
I have had mixed results with spiral bits, I love them, ut they can slip if not totally clean when tightened.
Marking: I take a block of wood, lay it up against the bit and the fence and draw a pencil line on both sides of the bit...that gives me my start and stop points. When marking up the stock, I continue the shoulder line around the stock, all four sides. It makes it rather easy to align the starting point/end point on the mortise and match that to the bit.
BG - So I don't really need a spiral bit to do this, just a regular bit is fine? -Yurij
Yurji,
I've tried Whiteside spiral bits in both the table and hand held mode and have had them break and/or slip out after very little use, so I just don't trust them all that much. They do cut easier but the regular bits cut too...so...not trying to sell anybody, just my personal experience.
BG - Thx, I'll use my regular bits and see how it goes. I am planning on making a mortise that is 1/2"W x 3"L x 1"D and have it inset from the edge of the leg by 1.5" (the leg is 5"x5" at the top). Should I have a 1/4" bit and make multiple passes to get the width, or a single pass with the 1/2" bit? (of course I have to make multiple passes to get the depth for any bit I choose). -Yurij
Yurji,
Personally I prefer to use the 1/2" bit so I don't have to move the fence. I just make sure the fence is square to the router table top, I align the marks on the fence with the shoulder on the stock and push down. After sliding down the 3" to the rear markings I'll either lift straight up or back up a bit and tilt up the stock from the right side.After the first couple of passes the bit is somewhat controlled by the previous cuts and the push down part is less tense... don't forget to have fun
BG - all of it is fun, except when its not.
I have had a lot of success with a plunge router and upcut spiral. The secret - as everyone has said - is to make light passes. That's when the turret depth stop comes in handy.I built a really complicated jig when I cut them before, but that thing was difficult to get and keep aligned. Now, I'm a big fan of using the edge guide to dial in the cut... works like a champ.Tom Iovino
Tom's Workbench
http://tomsworkbench.com
When I use the router table for this, I do as you do. However, I take a series of light passes and make the mortise just a tiny bit short on each end. I finish with a chasel. Works for me''Wayne
I also do it this way and it works just fine.
FB
Forget plunging. Make one of these. You'll have it forever, and it works perfectly.
Jeff
That is how I just complete my legs but with out the jig just the pc router and fence.Webby
Jeff - looks almost too easy. will give that one (but using plywood instead of solid stock) a try. -yurij
yurij
It doesn't matter what material you use, as long as it's wide enought for the router base to ride on without tilting. You can glue up several pieces of plywood to make it around 6" thick. My cherry block is 5" square, and was a leftover piece from some leg stock I had laying around when I made it. Just make sure, and this is critical, that it is square and true. Otherwise, your mortises will be off 90°, and your pieces won't register or fit properly.
Jeff
Hello Jeff,
I have the same router and guide. Could you give more detail of the set-up you are showing?
Bob, Tupper Lake, NY
It's the exact same mortising jig found in Jeff Miller's "Chairmaking and Design" book. It's simply a block of SQUARE wood that acts as a base, and a place to register the router guide to. It also has a channel in the back for the guide to run in, so it doesn't stray off course. It works well, and repetitive cuts are easy. Once you have one setup done, you can batch cut all the mortises without changing anything.
His book was out of print for a while, but it now is available again. It wouldn't be right for me to print his diagram to build it here. Buy his book, as it's a great book on chairbuilding anyway.
Jeff
Thank's for the info Jeff. I'll give the book a look; your description was quite good though.
Bob, Tupper Lake, NY
Jeff,Looking at your jig, what do you mean by forget plunging? Don't you still have to plunge the bit into the workpiece? Also, is the width of the mortise the same size as the bit or can you cut wider mortises than the bit?thanksQuaffer
I meant "forget plunging", meaning plunging the wood onto a raised bit on the router table.
I always use a bit that's the same size as the mortise, but you can definately make larger mortises in two series of passes. However, you'll just have to clean up the ends where the arcs meet with a chisel or gouge. I prefer to round the edges of the tenons, which is quick work with a rasp, vs. squaring up a mortise made with a router. It's simply a matter of speed to me. Time is money.
Jeff
I like it!I am short on cherry, but I have a nice piece of lyptus that will stand the task.
Thanks Jeff.Don
Edited 2/13/2008 9:21 am ET by Don01
Jeff are those stop blocks on each side of router.Thanks Randy
Yes. When I have a large batch of similar mortises to make, it makes sense to have the stops. I register one stop on each end of the mortise, and then I don't have to be careful about overrunning the length of the mortise. When I have one or two, I freehand it. When I have 72, like in a set of chairs, then it makes a lot of sense.
Jeff
Before I got a Woodrat, I used this for many years.
View Image
Edited 2/8/2008 11:18 am ET by knuts
Edited 2/8/2008 11:19 am ET by knuts
Edited 2/8/2008 11:19 am ET by knuts
I was at The Woodworking Show last month and ran across this jig called The Router Wizard to cut mortises as well as dadoes, rabbets, circles, etc.. I bought one and tried it at home and I simply love it! So easy to use and not complicating to set up. Does everything it says it'll do and more. Definitely worth a look at if you're in the market. http://www.eaglejigs.com/
Mvflao- The show is coming to NJ this weekend. I'll be sure to look this up. thx -Yurij
I checked the Somerset schedule and it looks like they may not be there (they're not mentioned as an exhibitor). You can view the demos on their website and get a good idea how the jig works. I paid $200 for the jig and after using it and seeing it's capabilities, I'd pay $300.
mike
I've done mortises a number of times on a router table. You only need one fence, as this sets the distance from the edge of the piece. A second fence would only get in the way. I've never seen the twist that some described, like most table routing you just hold the piece against the fence and the mortise will be parallel to the edge of the piece. A spiral bit is *much* better than a straight flute.
I don't use stops, I just make a pencil mark for each end and a pencil mark on the fence. Always start the cut in the middle, and take light passes each time. Also, mark your pieces carefully to avoid machining the wrong side.
Pete
Two things can make it inaccurate or dangerous. As you drop the work down, it travels in an arc. The deeper the cut, the more chance of catching or kicking.
I was using a simple mortice jig yesterday and took some pictures. The jig is nothing more that a piece of plywood with a groove, the same size as a template guide. There is an adjustable fence. I screw it to my front vice, it can also be clamped to the work. This particular template guide will take up to a 1/2" bit. To limit the length of the mortice, I put a plug in the groove. Attached to my vice, I can clamp a stop for the work either on the bench or on the jig, as it shows in the photo. You can make these in any size you need, a small cabinet mortice, like the ones I'm doing or large timberframe work. The groove doesn't have to match the template guide if you need large mortices. I don't recommend an up spiral bit with this jig, it fills the groove with dust and the guide won't move. I just use a straight bit. A plunge router is a big help, take a little bite at a time.
Beat it to fit / Paint it to match
Edited 2/13/2008 9:16 am ET by hammer1
Hi - I need to mortise 4 table legs. I was going to build one of the mortising jigs described in FWW and use a plunge router
Y
Build the jig and plunge in from the top. I have used both methods you are considering and like Steve said and illustrated, you get uneven mortises doing the blind plunge. The jig is just easier to use, doesn't take up as much space, and you can take it some place and work on site.
I have a crude jig I use all the time with upcut spiral bits and there is no problem with things getting clogged in the mortise. I like my router set up so much, I have not turned my hollow chisel mortise on in 5 years. Its sitting in a barn under a bunch of other stuff I don't use.
If you want a couple of photos of the jig I use send word.
please send. the cruder the better (jig that is). thx
please send. the cruder the better (jig that is). thx
Here's a few photos of the portable mortise tool. I welded up some threaded rods but you can get creative and build something prettier. The piece "B" is fixed to the base. The piece being mortised slides between the A and B parts. When you establish the mortise ends you place the stock in the tool. Transfer the mortise end marks to the A and B parts with a pencil. Take the block(the distance from the router base edge to the cutting bit edge and set the stop blocks and tighten the wing nuts. All of the mortises will be exactly the same length. I use one bit for 5/16 or 3/8 mortises. With the router it is very fast and the surfaces are very nice. I prefer squared mortises to the rounded ends but thats just taste really.
Lot's of people have seen this and they adapt it one way or another but its basically the same tool. I'd imagine over 25 years, maybe 30 people have measured that ugly thing and made one of their own. It is not an original design of mine by any stretch. I saw this idea being demonstrated in a book by Tage Frid and figured I'd try my luck. Very happy camper. I do a bunch of mortise work. I have no bisquit joiner or floating tenon equipment so... if it has stiles and rails and it comes thru Durham, it goes out with M and T.
Note: You are probably wondering why the threaded bolts are so long? The first generation tool was used to cut 200-250 mortises for a post and beam shop. After I was done making about 150 identical parts I converted it to a smaller tool. I was just hesitant to cut them down -- you know the first time you cut them somebody calls and asks: Could you do me a job like so and so over in...? I still haven't heard the phone ring. Oh well.
good luck and let me know if the photos are helpful enough.
dan
Edited 2/14/2008 4:22 pm ET by danmart
very helpfull. it looks almost too simple not to build! thx
Please pardon if this has already been mentioned, as I'm not going to read through 46 posts to find out. But you could avoid over stressing the router bit by making a series of plunges, rather than trying to move the piece with the bit that deep. That way you avoid the pulling, which is what would cause a crooked slot. After making the series of plunges, move the piece back and forth to clean up the mortise.
Just a thought I felt worth sharing. :)
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