I’ve recently constructed several projects using M&T joinery. I had some problems getting the shoulder tight to the mating piece. I believe I discovered two possible causes and I’m looking for both verification and direction.
Problem 1 – I’ve been using my Rockler miter gauge stop to cut the shoulder and I always seem to have a slight difference in the location of the shoulder as it goes round the stock causing a gap when the joint is fitted together. I’m thinking of using a stop on the fence instead – will this help? I also tried using my bandsaw to cut the tenon with mixed results, though I had not constructed any special jig for the operation and expect that this would help with the accuracy. Does anyone care to comment on bandsawn tenons?
Problem 2 – This one I kick myself for. I’ve been using a random orbit sander to prep my parts for finishing and, after finding that some joints did not fit as tight at final assembly as they did during test fits, I realized I must be rounding over the narrow edge of the board just a little causing a gap to appear along the shoulder line. So, what’s the best way to sand the narrow edge without risking a tight fitting joint?
Regard it as just as desirable to build a chicken house as to build a cathedral.
Frank Lloyd Wright
Edited 5/8/2006 11:09 am by Rennie
Replies
Whether I cut my tenons by hand or on a RAS, I leave them a bit proud. I scribe the exact measurements with an awl or marking knife. I place a pencil line just next to the awl scratch, on the waste side. I cut to the pencil line and leave the the tenon a bit thick (by ~ 1/16 to 1/32). I then finish the tenon- cheeks and shoulder with a shoulder plane or a little rabbet plane (e.g. a #90).
This allows me to ease everything to exact length/width/thickness. I use the scratch line to determine the shoulder (if you cut the line smartly with a marking knife, it can help to minimize tearout when planing the end grain). I plane the thickness/cheeks and stop and check against my mortise- I do a little on every side until it fits.
I don't sand the tenon at all. Any rough, torn fibers are crushed with the glue and will swell, improving the fit.
I don't have a production shop, so speed is not essential- and the time it takes for me to hand fit a tenon is small. Also, it seems to works well every time.
Just my 2p
Glaucon
If you don't think too good, then don't think too much...
The answer is to very slightly undercut the shoulders of your tenon pieces.
I can see that this would give the tight fit...on the sides. Forgive my inexperience, but how would you cut the top and bottom shoulders without either leaving a high spot or a notch in the undercut side shoulders?Regard it as just as desirable to build a chicken house as to build a cathedral. Frank Lloyd Wright
And that's the small booger-bear, it will be ever so slightly noticeble when the door is viewed from the top, when open.
You are maximising the aesthetics of the face-on view. This has been done for years.
If you want a tight fill all around, which is certainly possible, then you're simply going to have to cut a better joint with very tight tolerances. Your stock needs to be dead flat, square, and the ends MUST be cut perfectly square.
After having cut these things by hand for many years now, I really don't know how I ever achieved a good joint with machines. Looking back on it, I think it was blind luck. Marking out and cutting the joint by hand really ends up being easier than tweaking the machines and jigging to the level necessary to produce the perfect joint you're after.
The ROS is a lousy idea and your tablesaw technique probably needs sprucing up a bit.
A Starrett combination square and a marking knife combine to make a very powerful 1-2 punch as far as accuracy is concerned.
Edited 5/8/2006 1:35 pm ET by BossCrunk
Thanks very much for the guidance - I'll keep trying. My hand tool skills could use some polishing too.
One last question. ROS?Regard it as just as desirable to build a chicken house as to build a cathedral. Frank Lloyd Wright
Random orbit sander.
If I understand correctly, the shoulder of the edge (the short shoulder) is not on the same plane with the long shoulder, therefore you have a gap,
That is probably because the end of your piece is not perfectly square.
Cut your long shoulders first using the mitre gauge and the fence (you can do that because you are not cutting through).
After that move the fence towards the blade 1/32" and cut the short shoulder.
When you are done cutting your tenons, you can pare the short shoulders with a chisel using the cut of the long shoulders as a guide.C.
Problem 1 - I've been using my Rockler miter gauge stop to cut the shoulder and I always seem to have a slight difference in the location of the shoulder as it goes round the stock causing a gap when the joint is fitted together. I'm thinking of using a stop on the fence instead - will this help?
If your mitre gauge is not cutting evenly around the tennon, either the end of your workpiece that rests on the stop is not flat/square, your mitre gauge is not square to the blade or has slop in it somewhere; or the workpiece is moving sideways off the stop as you cut it.
You can use the fence to locate the work piece instead, as you suggest but you still need to ensure that the workpiece and mitre gauge are square to the blade and stay that way throughout the cuts. You shouldn't have the work piece actually against the fence as you cut, because the long work piece might catch, slew, jam and kickback. The fence should be used only to position the work before you make the cuts.
I also tried using my bandsaw to cut the tenon with mixed results, though I had not constructed any special jig for the operation and expect that this would help with the accuracy. Does anyone care to comment on bandsawn tenons?
You still need to guide the workpiece with a fence and mitre gauge. All those surfaces still need to be square. After all, you're just doing the same operations with a different shaped blade. Bandsaw cuts tend not to be quite as clean as TS cuts, all things being equal. This might exacerbate your shoulder-clean up issues.
Problem 2 - This one I kick myself for. I've been using a random orbit sander to prep my parts for finishing and, after finding that some joints did not fit as tight at final assembly as they did during test fits, I realized I must be rounding over the narrow edge of the board just a little causing a gap to appear along the shoulder line. So, what's the best way to sand the narrow edge without risking a tight fitting joint?
If you use a RO sander, get a hard pad for it so it doesn't deform around the edges. Not all RO makers provide hard pads though.
Just lately I've substituted a block plane for sandpaper when cleaning up sawn edges, including those arounf tenons. I tried planes years ago and hated the constant fettling and poor performance of the only ones I could afford then (Record). Now I have a Lee Valley and its performance is a revelation.
But if you still want to sand, hand sanding with a sandpaper-wrapped hard wood block is the time-honoured way, where 90 degree edges are involved. Its hard and boring work, I know only too well. :-)
Of course, you could get a woodrat - clean, square and perfectly fitting tenons straight out the machine.
Lataxe.
Sounds like you have just performed the test to demonstrate your miter guage is not accurate. ; -)
I usually cut tennons as follows:
1) set up the outside blades of a dado set with a spacer between them so they cut both cheeks of the tennon at the same time using a tenon jig. I have zero-clearance inserts for each commonly-used tenon size. Blades are raised just shy of the finished length of the tenon.
2) Cut the shoulders on the radial arm saw or table saw. Blade raised to cut the shoulders to the exact depth or a few thou' deep. For either type of saw, set up a stop to set the cut location exactly, cut it, flip it and cut it again. I prefer to cut square rather than undercut, but you could do either. NOTE: Do NOT use your fence as the stop. You'll bind the piece and have problems. Use a short piece of wood clamped to the fence well behind the blade so the workpiece is clear of the stop before it touches the blade. If your RAS or miter guage is not EXACTLY square, your shoulders will not line up on either end of the cuts.
3) If the tenons are not the full width of the piece, carefully trim them to the proper width, either with the formerly-described RAS or table saw method or by hand, using a dovetail saw or a Japanese pull saw. (I prefer the former. My wife prefers the latter.)
The other likely problem for poorly fitted shoulders is the mortise not being square. The mortise is far harder, in my experience, to get exactly square than the tennon. Requires lots of patience and accuracy in setting up the drill press, mortiser or router, depending on your choice of method. An out-of-square mortise will keep the shoulders from seating fully as often as problems with the shoulders.
Mike Hennessy
Pittsburgh, PA
Mike & Lataxe,
Thanks - really good advice. I have the Rockler miter, positive 90 degree stop (one hopes), so I think I'll check the miter slot/blade alignment. The stop on the miter gauge does have a bit of slop, though I though I had overcome it by really tightening it down. Perhaps not.
I've noticed that I often see a stop block clamped to the fence as the guide for cutting tenon shoulders in many published plans and magazines. Perhaps now I know why.
The ROS (I'm catching on to the lingo) does not have a hard pad - problem. I don't know if the DeWalt is available with one, but think I shall find another solution as I'm not sure I can trust my self to hold a spinning and vibrating machine exactly 90 degrees to the work piece anyway. The Leigh Nielsen solution is a bit out of reach for me right now....sanding block, here I come.
The woodrat is a fascinating machine. Maybe someday......
Have any of you had any experience with the Leigh FMT? The local Woodcraft has one in its discount pile (bad sign?) at a good mark down.Regard it as just as desirable to build a chicken house as to build a cathedral. Frank Lloyd Wright
Lay the joint out by hand and then cut with your machines. You'll quickly see where the problem lies.
You need a Starrett or other good quality combo. square to check for square ends... as a check on your machine set up and technique if you will.
I'd second this. Laying out the shoulder line with a knife and a square may tell you a lot. It also shows the precision needed to really get tight fitting tenons.
Sanding isn't precise enough to be used prior to glue up of most M&T joints, which should be planed or sanded together so rail and leg, for example are exactly flush. (Those little set backs you see in factory furniture are mostly to hide the lack of precision--a rail set back 8/64th" won't look different from one set back 9/64th" but let it be 1/64th proud of being flush, and it will scream. ) That's one of many reasons why bench made furniture is so often better than factory made.
My tenons are made on a RAS and are generally too big for the mortise. I then take a chisel and pare them to fit.Regards, Scooter"I may be drunk, but you're crazy, and I'll be sober tomorrow." WC Fields, "Its a Gift" 1934
R,
I have no experience of Leigh jigs as they look too expensive and are also in my classification of tools labelled "only does one trick and therefore not good value". M&T is a pretty fundamental trick, admitted; but why spend all that money on a one trick pony when a woodrat will be a ball-balancing seal, a hoop-jumping alsation and a dancing giraffe as well?
Lataxe
By 1920, at the latest, the Industrial Revolution presented mankind with a machine that would cut all the relevant woodworking joints needed to build a piece of furniture. Industrial sized dovetailers by Brookman, Wadkins, et al. are but one example. With a few weeks of training the completely uninitiated could run these machines and create perfectly fine joints. They became excellent Brookman Dovetail Machine operators. They were not woodworkers.
Charles,
Nomenclature and taxonomy are useful conceptual tools but do not necessarily reflect the surprises of reality nor even the predelictions of personal taste.
When woodworking becomes a religion, inclusive of dogmas, catechisms, priestly hierarchies and inquisitions operating via rules of heresy, I shall take up juggling, on top of poles and also in the dark.
Meanwhile, can you send me one of those Brookmans to play with?
Lataxe, a self-declassified life-form.
Good luck with your juggling and good luck with your Woodrat. The two are not mutually exclusive. The latter will leave you plenty of time to learn the former, and I'm sure that must be comforting.
Edited 5/13/2006 7:54 am ET by charlesstanford
Charles,
Thank you for the comfort. I need comfort because I am becoming old, silly and cantankerous, as you can probably tell.
I caught the lady-wife reviewing the life insurance policies just the other day. She has probably forseen a serious juggling "accident". (He really wasn't safe up that pole, officer).
Lataxe
because I am becoming old, silly and cantankerous,ME TOO! NOW the kids don't ask me so many stupid questions...
Will,
I practice cantankery on the grandchildren, via the exciting characterisation of "evil grandad". This involves hobbling rapidly after them waving a gnarly length of wood and threatening to eat their livers, dismember them slowly and so forth, as they run off squealing.
For some reason they seem to enjoy it, possibly because I never seem to catch them and often trip over my own gnarly stick, to hoots of mirth.
I'm lulling them into a false sense of security and always carry my bottle of Special Liver Sauce for the Moment of Truth.
Lataxe, an old fool.
Edited 5/18/2006 8:00 pm ET by Lataxe
I'm lulling them into a false sense of security??They know YOU BUT still SCREAM! They enjoy it... "evil grandad" Yep wnen they want ME to go to the park with them, and I say NO , because it is 4 miles away and I'm tired of pulling the waggon they sittin' in!BUT I do it all the time! Sure hope they they get 18 or so and go off on their own way! God love em!
Edited 5/23/2006 11:22 am by WillGeorge
Will,
They might go their own way at 18 but if experience with my daughters is any guide, the little boogers will be back regular-like to dip in my wallet, AGAIN!
Even a gnarly stick can't fend them off.
Lataxe, a pensioner who is a bit poorer than he planned.
Lataxe,
"When woodworking becomes a religion, inclusive of dogmas, catechisms, priestly hierarchies and inquisitions operating via rules of heresy, I shall take up juggling, on top of poles and also in the dark."
Buddy, I'm sure that you've been on this forum long enough to know that there are a few members here of the Church of My Way is the Only Way.
However if you choose to turn your own pins to juggle, and work the pole down from a spar you felled yourself, we'll be here to tell you how best to do it! Esp if we've not done it (or anything similar) ourselves.
Here's my advice, for starters: Open the door to the sanctuary with a pull-stroke. Kneel at the altar of L-N first, and then annoint yourself with camellia oil.
Cheers,
Ray
Ray,
<<Open the door to the sanctuary with a pull-stroke. Kneel at the altar of L-N first, and then annoint yourself with camellia oil.>>
ROFLMAO: Thou hast slain all of mine sacred dragons in one fell sentence....
<<still chuckling...>>
James
Edited 5/17/2006 12:59 pm by pzgren
James,
Your levity amounts to blasphemy. Bend over this granite slab, while I give you 20 lashes with a sheet of 60000 grit.
Ray
Ray,
Please sir! Anything but the 60000 grit!! I promise, I'll never do it again!!!
James
This observation is based on my experience only. But if there is any slop in your Rockler miter gage then it is a piece of junk. But I think that you already suspect that. Incra makes a reasonable miter gage for about $59, I think that they call it a V29. Install a wood subfence, apiece of quartersawn oak and cut it to lenght for both miter gage slots and you will always know were the cut line is. This miter gage is both reasonably priced and, once it is adjusted,it is very reliable and easy to use. Quit trying to do precision work with junk. The two are not compatible and very frustating to boot.
I get better fitting tenons by eliminating the cheek cuts by nibbling the sides of the tenon in the tenon jig. Mine is home-made and slips over my BT3100 table saw rip fence. Using the micro-adjust it is easy to move the fence in 7/64 increments until I have the thickness of tenon I want. I then reposition the fence and cut the ends of the tenon with the table saw height the same. This does not always give me perfect tenons, just better than when using a stop and the sliding miter table of my table saw or my radial arm saw with a stop. To get it perfect, I think I will have to get a Vertas shoulder plane.
The other technique that I have tried is a horizontal router table and a spiral carbide bit. That works pretty well and is fast but again the shoulders are not always perfect.
I have also undercut with a chisel but it takes a long time and is difficult to do much more than improve things a little.
Jim
First make sure the end of the rail is square. Clamp a block to the fence before the blade,so the stock passes the block before cutting. The distance from the block to the blade is the shoulder. Make a pass.turn and repeat until all four sides are cut. If you set up the saw correctly and the miter gauge is square,then the shoulder will line up all the way around.Make sure blade is squre to the table.
mike
This forum post is now archived. Commenting has been disabled