At the risk of reopening old threads (and wounds), being new to this group, I need advice on biscuit joints. While I would pure-D love to use them everywhere, including panel glue-ups, my joints are too loose. I use a Porter-Cable joiner and Porter-Cable biscuits. Why do them seem too loose to help me align edge glue-ups? Am I asking too much, or is my blade out of whack, or are the biscuits bad? Thanks for any advice.
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Replies
They are supposed to have a little slop left and right. They also should be a snug fit or less top to bottom. When the glue gets absorbed, they are supposed to swell and lock in place.
If your slots are wobbly loose, the first place I'd look is at your technique; you may be tipping your cutter up and down during the cut.
Of course, this also begs the question whether or not biscuits are designed to be alignment aids. One which I shall not answer.
It's normal to have a little bit of slop between biscuit and slot, up to about 0.2 mm (0.008") or so. And since the tolerance applies to both halves of the joint, you could see up to twice that amount if you rattle the joint back and forth.
The nominal slot width is 4.0 mm (0.157"), but I think up to 4.1 mm (0.161") is considered to be good. Likewise, the nominal biscuit thickness is 3.9-4.0 mm (0.154-0.157").
I've checked my Porter Cable joiner, and the blade width is dead on at 0.157". The resulting slots are typically 0.158-0.160". There seems to be a lot of variation in biscuit thickness, even within a single batch, but the intent, at least, is that they will invariably swell enough to fit the slot when wet with glue. Most of the time, I find that the biscuits fit the slot pretty loosely when dry, although I occasionally encounter a "linebacker" biscuit that's a very tight fit.
-Steve
Has there been a problem with this jointer before or is it new ? I took in a return a few months ago and found the blade had a wobble and that surely will make a sloppy slot. The chap only had it a few hours.
Work Safe, Count to 10 when your done for the day !!
Bruce S.
IMHO they are a complete waste when used in panel glue ups. I do however love them for face frames, dust frames and the like.
When I worked for a tool dealer we only carried Kaiser or Lamello biscuits. They were the most consistent. Biscuits are a waste of time for panels. Cauls do a better job of aligning the boards.
I got called out of town unexpectedly, but I'm glad to get everyone's comments. My PC joiner has been cutting "loose" slots forever, and a second machine gave me the same results. I have tried very hard to use good technique, but it is always a possibility that I'm doing something wrong. It sounds like biscuit joinery is not the way to go for alignment of panel glue-ups because of the inherent play side-to-side. My experience is also that with practice and cauls, panels can be made pretty flat. I was hoping that there was some clear step I could take to make life easier in this regard. Okay, how about aligning/gluing/trimming solid wood edge banding on plywood panels? My latest monumental migraine involves a project where I thought it would be really classy to edge high-quality 3/4 birch ply with 3/4 by 1" solid birch. After fighting the real vs theoretical thickness of birch plywood, the bowed birch stock on hand, and the 1 molecule thickness of the birch plys and their apparent death wish when a sander is even turned on in the same room, I am now going to iron-on edging. Is there a way to make solid wood work that is not subject to the vagaries of a fool such as I? Splines? Tongue and groove? Prayer? Thanks.
Kingsun,
Use splines. Cut the grooves with the show face of each piece registered against the fence, and cut them all at the same time. One set up only. Then make your own hardwood splines. Cut them oversize and use your planer to take them down 1/64" per pass until they fit snugly. If this is done properly you would have to try to get an uneven surface.
Rob
Edited 12/18/2007 10:04 pm ET by Rob A.
I have tried very hard to use good technique, but it is always a possibility that I'm doing something wrong...I do not have a PC biscuit cutter. I have a inexpensive Ryobi. It works just fine but I do have to admit that I do not use biscuits that often but I find them helpful during glue up of panels. Just for keeping things aligned while clamping.Try clamping a scrap of wood to your bench and set your cutter flat on the bench. Make the cut while making sure you are holding it flat to the bench. If it is a good fit, it is probably your technique. If the fit is not good then you used two bad tools.Just a thought...
Edited 12/19/2007 10:24 am by WillGeorge
King,
You also ask:
"Is there a way to make solid wood work [as lipping on veneered ply)"?
There is!
Make your lipping a little over size. Eg if the ply is 18.2mm (a not unusual thickness for "3/4" ply) then make the lipping 19mm or even 20mm. If your stock is bowed a lot and you don't fancy the biscuits to align lipping to ply-edge, then make the lipping even wider.
You can stick solid lipping to py with no spline, biscuit or other aid, if the surfaces of the ply-edge and the lipping are well prepared - ie smooth and flat/90 degrees across their width. Those ply layers that are long grain will glue well to the long grain of the lippng.
Once you have stuck lipping to ply edge, you should have a slight overlap of lipping on each side of the edge. Now run a router with a bearing-guided straight bit along the top of the lipping with the bearing agin' the ply and the blades across the whole depth of the lipping-side. This removes the excess lipping and does not touch the veneer of the ply at all. (The bearing and straight bit diameters must obviously be identical).
There are many bits of this kind. I like to use a 1/2" shaft CMT one that is 20mm diameter, with a 2 inch cutting length and shear-cut angles on the blades. This gives a very smooth and perfectly flat, co-planar side to the lipping.
To help keep the router flat on the edge, clamp a batten to the ply/lipping panel, co-planar with the front of the lipping and on the opposite side from the lipping overhang you are routing away. Repeat on the other side.
I've made many a carcase of 3/4" veneered blockboard, typically with solid lipping around 1" deep. I use the biscuits to get the show face of the lipping lined up perfectly with the panel from the start (so it can be done) and leave only 0.5mm overhang on the other edge of the lipping to be routed off.
Incidentally, you can avoid spelching the veneer if you cut the panels with one of those TS blades having 45 degree ATB teeth. With a zero-clearance insert in the TS, these blades leave a super-clean cut even across the grain of the veneer; and in timber veneers that are often inclined to spelch (eg oak and ash).
Lataxe
EDIT: Have a look at http://forums.taunton.com/fw-knots/messages?msg=29649.9
Edited 12/19/2007 2:25 pm ET by Lataxe
"Spelch" was a new word to me. A Google search for the term ran into a few x rated definitions but none that, I hope, apply to woodworking. A British word?
John W.
John,
"Spelch" is a word I've used all my life but it may well be Northern English slang. It means, those rough spelky edges you get when you cut across the grain with a rough saw. A piece of wood with a spelky edge is said to be spelched.
Presumably the word is related to spelk and to spell. "Spell" is a Northern English word for spelk; or any thin, long, pointy piece of wood - as in the pointy-ended slats used as the mainframe for woven oak baskets - "swills" as they are called in Cumbria.
These words have the sound of Norse or one of those other old Northern European languages. There are many such words in both Northern English local slang and embedded in the old place-names of Northumberland, Durham, Cumbria and Yorkshire. Over the centuries since the Romans left, there were waves of such Northern Europeans settling in what are now those counties, then being displaced by the next wave, often leaving behind remnants of their language.
Lataxe (another old Cumbrian word, for froe).
John,
I'm with you on that one. I still haven't figured out what he means by memes?
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
http://en.wikipedia.org/wiki/Meme
Biscuits come in different sizes. Make sure you have your joiner set to cut the properslot for the biscuits you are using. I think the sizes are 0,00,000??? It's been so long since I've used a biscuit joiner....I've forgotten. Good luck! =: )
King,
Have a look at:
http://forums.taunton.com/fw-knots/messages?msg=31220.17 et seq
A good biscuit jointer should cut slots of exactly 4mm kerf, no more no less. I like my Mafell jointer but Lamello are worth the money, according to the folk I know who have one. Porter Cable have had good reviews in the past but perhaps the bean-counters have been cutting their manufacturing costs of late.....?
Usual causes of slop in the slot are:
* bad technique (but it is easy to learn the proper technique)
* blade slop on the arbor
* blade wobble because the blade itself is not "true"
* teeth are not all 4mm wide, perhaps because they have burnt stuff on them
* fence moving slightly
* using a dirty or not-flat surface to register off, causing up/down movement.
Cheap biscuits are also to be avoided. Lamello, Trend and Tanselli are good, in my experience (of using thousands).
***
Despite what the naysayers cry, biscuits ARE good for alignment, where alignment is otherwise a problem (long, bowed boards etc.). Them naysayers may use great unweildy, heavy and inaccurate cauls if they wish but why do they criticise the innocent biscuit, espcially if they have no meaningful experience with them?
Lataxe, a biscuiteer.
" teeth are not all 4mm wide, perhaps because they have burnt stuff on them"
Lataxe,
Wilst skithering to and froe (ugh) through your post, it ocurred to me that I have never cleaned the blade on my jointer. Removing 18 or so years of crud from the blade makes a differance: the biscuits now must be pushed into place rather than dropped in.
Now, when I am biscuiting, must I say "O Grandma, what tight biscuits you have"?
-Nazard
I have a DeWalt, and it cuts the slots too narrow. That works great for panel glue-ups, but not for joints. I have to discard about half the PC biscuits I use. Either that or reset the cutter by a hair. Biscuits have almost no holding power if one has to tap them into place as I've found to my surprise.
ne sutor ultra crepidam
Take a few biscuits and nuke them in he microwave, about 20 seconds for a dozen. This will shrink the biscuit if they have swelled from humidity. If this does not do the trick, try replacing the blade. I have a dewalt, works fine. I do not use biscuits too often, but have found lamello biscuits are the best.
mike
Thanks. I try that at the next opportunity.ne sutor ultra crepidam
I sand biscuits that are a bit too fat to fit their slots. Just a few swipes on a flat piece of 80 grit paper and they usually click right in. I'm too cheap to throw the fat ones away...
Yeah, to anticipate your questions, the ends of my fingers do hit the sandpaper sometimes on occasion. I've given up aspirations of being a hand model. At least the flecks of blood don't seem to interfere with the glue strength.
Zolton * Some people say I have a problem because I drink hydraulic brake fluid. But I can stop any time I want.
Zolton,
Safecrackers used to sand their fingertips so they could feel the tumblers click into place. Second career?
Ray
Ray,
Just what I need - a second career, in crime! I have a hard enough time just getting through the day as it is. I couldn't handle looking over my shoulder for the bulls all the time.
Thanks for the suggestion though. I'll keep it in mind if things get too desperate...
Zolton* Some people say I have a problem because I drink hydraulic brake fluid. But I can stop any time I want.
I build cabinet doors and use biscuits to align the panels. I have the Dewalt jointer and use Richelieu biscuits (box of 1000) with great success.
Only issue is with swelling, sanding flat, then biscuits shrinking and leaving depressions in the panel.
I now do not use glue in the biscuits (doesn't add strength to laminations anyway), and wait for several days to make sure all the glue is dry before sanding. They are simply there to help with alignment.
Nathan
kingsun,
Just so your education in this matter is as rounded as possible, you should be aware that there is a considerably sizeable population of woodworkers who find no use whatsoever for biscuits (the non-edible kind).
In addition to those above who have so correctly described them as useless for panel construction, I advise that they add absolutely nothing to one's woodworking efforts for any kind of construction.
Alas, in today's intensely gadget-oriented world, they have become a legend in their own time. Please don't misunderstand, I am anything but a Luddite. I've bought some very expensive wood working machinery, and covet yet more. I love gadgets. But a biscuit cutter will never be on my list.
Biscuits do not add strength to any wood joint. At best, they may aid a bit in alignment, but there are much better ways to accomplish that. They can pose problems due to swelling of the surfaces of the joined pieces and can actually weaken joints by removing gluing area from the joining surfaces.
There are so many better ways to get the job done. Any joint you are contemplating with a biscuit in mind, you can learn to place a proper mortise and tenon or a spline tenon joint, just as quickly, and have a REAL joint. And the satisfaction that you know the difference.
Rich
Edited 12/19/2007 5:54 pm ET by Rich14
Rich,
I see you are still trying to blackmail Lamello into giving you one of their pitch pocket mending machines, by cursing the biscuit jointer until they send you the parcel-bribe-gag. However, you give yourself away when you mention that, " I love gadgets. But a biscuit cutter will never be on my list".
In short, you have no experience of them then? This must be why you know nowt about the lurverly little plaques and their winning ways.
I've said it afore and I says it agin'. Biscuits are good, nice and the best thing since the cauls were burnt in a ritual fashion and we all danced around the bonty chanting, "Good riddance, you silly old things". (So big and heavy they were, they burnt for days and days).
Lataxe, a bis-cute scientist
Lataxe, you auld blighter,
"In short, you have no experience of them then? "
Or, as my brother once tried to lead me to believe, "Ten billion flies can't be wrong. Eat $hit!"
What? A fricken dowel jig isn't candy @ssed enough, ya gotts ta get yersel' a biscuit cutter?
Whatever problem the biscute is a solution to, there is a better traditional cure for it; that has been proven by the test of millennia of stodgy ole craftsmen, real men who earned their bread by the sweat of their brow and the use of their brawny arms and honest to God tools, not some little pi$$y a&&ed motor with a 4toothed blade on th'end of it. Look at Mel, for example, don't see him tryin to hog out a bowl with a biscuit cutter do ya?? Naw, he's using a piece of curved STEEL on a STICK, as the Creator intended.
Haaawwk!Ptooie! Turned head, hocking a loogey onto the dust of the wagon yard. Might as well Emulate NORM (ptooie) and use a air nailer ptooie ptooie.
This world comin to? H3ll in a handbasket, you ask me.
Y'orts ta call yourself Biscaxe, stead o' Lataxe y' wanna know what I think. Mebbe Exlaxe, y'ol bag o' ...
Your one true friend,
Ray, the traditionalist-who thinks electricity should be used to power great whirling cutters that can eat a hand off, not little bitsy wheels fit for trimming hangnails. Woodworking is sposed to be risky, else it ain't fun nor manly.
Cuh!
This is why I look forward to reading Knots. Best post I've seen in a long time!
You ought to write a book, Ray. I'll be first in line to read anything you publish.
Oh Jeeesh, now you've done it!
Regards,Bob @ Kidderville Acres
A Woodworkers mind should be the sharpest tool in the shop!
t_
Thank you. You are the second person that has told me I should write a book. The other was my best friend. Sounds like a publishing run of, oh, three copies, ought to do the trick?
As well written as you thought it was, my post failed in its purpose however; to elicit a snarl and snap from he of the Land of the Biscuit Lovers.
Ray
Edited 12/21/2007 1:58 pm ET by joinerswork
We could sell them for $10,000 a piece, and then everybody would want them.
We would be the Marcou/Holteys of woodworking coffee-table book publishing.
t_
"We would be the Marcou/Holteys of woodworking coffee-table book publishing"
Yes, except for the quality...
Ray
Ray,
I yam practicing Haaawwk!Ptooie! as it seems wrong to engage you in snarling unless I can hit the spitoon with unerring accuracy; and even shift it few inches along the bar room floorboards, to the amazement of the gamblers and floosies.
Meanwhile I have sent Swiss men to deal with you in that cold and callous fashion they adopt when wronged. "Ah, zso; you do not like our Lamellos, my fine fellow. Ve shall soon have you zaluting our little red logos and prazing derr biscuit"!.
They are going to put you in a Plano Press then give you another slot or two, I suspect. I do not know to what you will then be joined......perhaps some near-completed scuttle-legger in the back of your shed, that already looks half human.
You will be like a woodworking version of Seth Brundel.
"Zere...now you underztant how ze biscuit is goot for aal styles. Iz aal clar? Here ist your compulsory Lamello".
Lataxe, trying to remember how snappin' goes (just bit my own lip agin).
Lataxe,
Now I verstehen the reaction of the Zweitzer visitors. I szought zhere axzent vas from Osterreich. No vunder zhey schtarted shpitting und schwearink at mich.
No matter. You see, I introduced them to the wonders of American beer, and the way it can be used to swell them biccies so they can be stacked hundreds high and used to lift Lamellos onto their pedestals.
Cheers.
Ray
Hi Rich,
Biscuit cutter: A solution for a problem which didn't exist.
Ray
Ray,"A solution for a problem which didn't exist"That's exactly the answer I was going to give to Lataxe in response to his assumption that I haven't used a biscuit joiner.We had a Lamello in the shop in the mid 80s. We used it on and off for several years, actually trying to like it. It was well made, and performed exactly as described. But we simply could find no compelling reason to use it.Biscuit joiner technology, especially in a small shop is truly as you described. There are so many other ways to facilitate joining 2 pieces of wood, most much better.But, as I said, we live in a gadget-oriented world, and the biscuit joiner has become a phenomenon in woodworking.Rich
Rich,
Biscuity gadgets..... Mmmmmmmm!
Lataxe, Playboy of The Western Shed.
I bought a new porter cable joiner from H.D.Had to return it. It cut big sloppy holes.There was alot of play (wiggle) in the blade.
Oh Grandma, What Loose Biscuits You Have
I thought the best title ever in HERE...
Under sized biscuits are normal, the glue swells them to fit.
For panel glue-ups they do not add any strength, and no matter how carefull you are they will not allign perfectly so they are not usefull for that. If your boards are jointed flat you can get perfect allignment by using a dead-blow mallet with the clamps loosely applied. The biscuits will only frustrate this.
On very large glueups where there is not time to use the mallet technique before the glue sets up biscuits are a big help. However there will still be some beltsanding/ handplaning to level the joints.
Biscuits really shine when reinforcing endgrain joints.
Pardon my spelling,
Mike
Make sure that your next project is beyond your skill and requires tools you don't have. You won't regret it.
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