Hi,
I’ve used biscuits for trim and the like but never on a face frame type contruction. I was dubious they would be very strong but figured thte FF would be attached so it just had to hold it’s shape till tied together.
84″ x 24″ made of 2 9/16″ rails and stiles with #10 biscuits. I have a small shop/garage and have to move the assembles FF from place to place. Last place I put it was too close to where the garage door opens. The large, heavy, powered door catches the one corner FF about 90% open and drives it on angle into the floor. The FF stops the door. It’s being pushed on opposite corners, the weakest link of a rectangle. I can’t get it out! It’s completely wedged! The door won’t open or close it’s so wedged. I finally have to pound it out carefully and the door swings continues to wedge and open the entire way.
Anyway. The FF is fine! Not even out of square! I thought it was wasted for sure. I’m really sold on the biscuit approach!
Thought some of you who aren’t sold on biscuits-like me till yesterday- might be interested.
Notrix
Replies
Glad the FF wasn't damaged and it is pretty amazing how it held up so well.
Your next "sale" should be for a new garage door opener... Anything made in recent years has an automatic sensor in it that will stop it from closing if it hits something before fully closed... this is to keep it from killing pets, kids etc. who try and "sneak" in before the door closes.
Cya, I gotta go dust off my biscuit joiner. :)
Donald
Thanks for the shop tip. Now I can throw away my veneer press....
Notrix,
I've been involved in this debate for a long time, and I've consistently come out in favor of biscuit joints. Although I never had a garage door close on my biscuits, I've used them to join shelves to walls in bookcases, to do long tabletop glue-ups, and to join aprons to legs in a table. I even made a rail-and-stile linen cabinet using biscuit joints to hold the pieces together. All of these were among my first woodworking projects, when I was still learning the basics. They are all as strong today as they were seven years ago when I first made them.
With that said, I no longer use biscuits for a lot of the above-mentioned joints. But I have chosen other methods for reasons other than strength.
I think a lot of woodworkers dislike biscuits because they do not want to believe it.
Fine Woodworking did a thorough test a couple of years ago, and the conclusion was that a biscuit joint will fail under less pressure than a mortise-and-tenon joint, but the pressure it takes to make a biscuit joint fail is still beyond what most of your household projects are going to endure. Also, there is the "degree of failure." Under a certain level of stress, a mortise-and-tenon joint will fail, but not completely. Under the same stress level, a biscuit joint will fail completely. However, if I build a table and the joints fail 60%, the project is ruined as far as I am concerned. I have to re-do the project in that situation whether it has failed 60% or 100%. But again, the stress level needed to cause this level of joint failure was so high that it will not be an issue with most household projects.
Conclusion: biscuit joints add adequate strength for most household projects.
Just to sprinkle a little lighter fluid on the embers . . .
Biscuits are for alignment of joints, not as strength-giving members to the joints. Like dowels, they make assembly easier in a production environmentand and are more useful than dowels.
In a non-production situation, in most cases, the joint being biscuited has no need of them (ex. edge joining boards for a table top and the like) and they actually weaken the joint by taking up glue surface. They cause additional problems such as telegraphing their presence if the joint is not allowed to cure for a time after gluing (at least days, if not weeks) before sanding.
Almost all joints that do need a strengthening member (a M&T type of joint) receive little or no benefit from a biscuit and really need proper construction.
Those who agree will continue to use traditional joinery methods. Those who don't, I wish you nothing but the best with your specialized cutters and biscuits.
Rich
Edited 2/1/2005 3:06 pm ET by Rich14
Edited 2/1/2005 3:08 pm ET by Rich14
It seems to me that the face frame example that started this thread is a direct contradiction to the statement "Almost all joints that do need a strengthening member (a M&T type of joint) receive little or no benefit from a biscuit and really need proper construction." Nobody is arguing that a biscuit joint is as strong as an M&T, but it seems clear that there's more going on than alignment in the case described, and reasonable that this amount of strength has appropriate application.
Alan,
I'm a charter member of the American Society for the Abolishment of Biscuit Joinery.
I build my stuff to last. Yeah, I've seen some of that biscuit-jointed stuff. Some of those cabinets won't last more than a hundred-fifty, hundred-seventy-five years.
And you don't even want to get me started about Pocket Hole Joinery!
Rich
Rich,
Like I said, I no longer use biscuits for some operations, such as gluing up table tops. But I still use biscuits for operations that you and others may think are wrong. For example, two years ago I built a series of nested tables for a friend, and I used biscuits to join the legs and aprons. They have a two-year-old daughter who climbs on top of the tables all the time. When the little girl's friends are over, they do the same thing. After two years of rugged abuse, the legs haven't budged. I don't know which is more intense, a garage door closing on your face frame or two-year-olds climbing on top of a small table top! But both examples demonstrate that biscuits do certainly add strength.With that said, I agree that there are certain projects where biscuits are not appropriate. For example, I recently built an exterior door, and I would not use biscuits there. I built a cheval mirror, and used pinned mortise-and-tenons there, and the same goes for a couple of medicine cabinets I recently built. But I did this for esthetic reasons as well as strength. Yes, mortise-and-tenons are STRONGER; but that doesn't mean that biscuits are weak.Here's a good test. Build two miniature shelf units, say 12" high and 12" wide. In each one, glue the shelf to the wall using edge-to-face joints -- no dadoes. In one of them, use biscuits to join the shelf to the walls, and in the other use biscuits. After letting both set for the night, jump with all your weight on the shelf of each unit. Tell me which one survives longest. And tell me the position of the joint failure in each case.
Edited 2/2/2005 10:48 am ET by Matthew Schenker
Matt,
I don't want this to spiral way out of control as many threads about these subjects can . . .
I think that workers who know what they're doing can make just about any technique succeed. It's the knowledge of the materials and the stresses.
But there are so many who are drawn to equipment for equipment's sake. The incredible popularity of biscuit joinery, without any understanding of joinery, glue properties, etc. I think a lot of it is driven by the manufacturers of this equipment who must be delieriously happy with sales of plate joiners.
But then, long before this phenomenon, we had (and still have) the public misperception of the goodness of doweled joints. Same kind of misunderstanding of a process.
I personally do not think that the use of biscuit techniques benefits or improves the work of a non-production shop in any way at all. (Emphasize NON-PRODUCTION SHOP) At best, the techniques are unneeded, marginal replacements for a number of traditional joints. They save no time or effort. At worst they foster very poor workmanship. And it's unfortunate that many are drawn to such technology because they mistankenly conclude that the existence and proliferation of the equipment implies "professionalism."
I do NOT want to start a war here. There are workers who can use any technology available to construct beautiful furniture that will withstand tsunamis.
Rich
Rich,
There's no reason for this subject to spiral out of control. It's not like I own stock in Lamello or anything!Seriously, I agree that there are many projects where biscuits have no place. I agree that mortise-and-tenons are much better in the majority of projects, and biscuits don't add anything to long edge-grain-to-edge-grain glue-ups.I'll also say that as I got better with my joinery methods, I found that biscuits did not even save me much time! One of the main reasons I began using biscuits less is because it's extremely frustrating when half the biscuits are too big or too small.So, my point is, I agree that biscuits have relativelty limited use in woodworking. There are certain projects where they really help out, and you have to learn to recognize what those are. My only argument is that it just isn't true when people say that biscuits add no strength.
Hmmm....First I'll requalify by saying I never trusted biscuits, think the joiners are too expensive. I have one for trim carpentry where the value would have to be argued elsewhere.Never the less I take issue with some of your staetments. First I'm not a production shop. Recently I've been able to come up with about $2000 of woodwork business a month. 25%-50% built in cabinet affairs. Before I used biscuits for a faceframe that would be attached to a ply wood box I would use half laps that I made with a router and jig or a friends-who has since moved- RAS with dado. I can say unequivically the biscuits are faster and as my garage door test proved have ample strength. Previously I would attach the faceframe with one of several approaches, nails and glue or in combination with a dado on the back of a face frame. Sometimes a decorative doweled joint. Now I have learned how to use biscuits. Once again much faster and more than ample strength. And no nail holes to patch. Now if I was building say a Krenov type cabinet, custom, free standing, I would most likely not use biscuits but on reflection know Mr. Krenov uses dowels. So.... Who knows. Biscuit joinery can be quite useful in any type of shop. As with any woodworking joint the knowledge of it's benefits and drawbacks must be learned so the woodworker knows the proper application. The use of biscuits in no way shape or form fosters very poor workmanship.Notrix
"The use of biscuits in no way shape or form fosters very poor workmanship."
I will agree with your statement. Biscuit joinery is another in the woodworker's arsenal of joinery techniques.
Some people sniff when their thoughts turn to biscuits or, for that matter, pocket hole joinery.
There is snobbery in woodworking just as there is in any endeavor.
I've used all forms of joinery from biscuits to M&T to tongue and groove to dowels to pocket holes. It depends on the application and my judgment.. not on someone's view of what constitutes fine furniture.
Relax guys,Read the last line of my post, why doncha.Rich
Don't ever learn anything new. Rather than give you satisfaction that you know more than you did, it will only confirm you know less than you thought by opening horizons to things of which you had never dreamt and which you now must explore.
Well..... I think the point is, the point I'm making at any rate is it might be nice to know how to make as many joints as possible as quickly as possible and where and when to use said joints. Dowels, biscuits, Miller dowels, screws etc... For me I've found biscuits can make some quick money for me. I have a reasonable handle on what to expect of them and lean towrards Rich14 in being less than trusting of them. My original post was one of extreme suprise! I'd have bet the thing would have collapsed at half that pressure! What I find with wood working in particular is my mind envisions a project a certain way, then process in sort of swiss cheese blueprint. I can see exactly how much of it will go but some is a mystery till I get to a point. I like to work this way. For years biscuits just didn't fit the way I saw things. I was strictly mortise and tenon, but I had better machines or more time at hand.Take pocket holes. I've yet to fit them into my schemes. They just don't fit my modus operandi. I could could copys Rich14's post and substitute pocket scews for biscuits!Oh well, all friends here just having a good banter.N
Rich,
Don't worry about it! I greatly appreciate hearing what you have to say.Really, I think it's good to have productive debates like this on woodworking techniques. It's the best way to share knowledge. When I was first learning about woodworking, these kinds of discussions were a real help to me, and I hope the one we're having now helps another new woodworker lurking out there. Even if you're an intermediate woodworker, these kinds of debates make you mull over your notions of what works and what doesn't and hopefully push you to develop further.In the end, there are two goals here: (1) connect with people so you can gain more knowledge; (2) use what you learn to improve your talents.Like I said, I do not have any vested interest in any particular technique.
Edited 2/3/2005 5:24 am ET by Matthew Schenker
Matt and Notrix,Agreed.Rich
Thought I would hop in here.Sounds great that you are doing 2K per month. Keep it going!I've worked in furniture and cabinet shops and have no problem with biscuits, they have their place and I'm not going to say when and where. Thats up to the craftsperson.I will only make a suggestion that you might consider pocket screws using an automatic pocket cutter like the Kreg Foreman or Porter Cable. Better yet an industrial machine like a Castle if you have the room.Yes, biscuits are stronger but with a FF cabinet that isn't as big of a concern as they get attached to the box anyway and then attached to a wall. And that is where a built-in gets most of its stability.Anyway I went solo about nine months ago and thought I would use biscuits instead of the pocket screws since I didn't have that equipment. Well, I did one job (basement remodel 10 cabinets) with
biscuits and bought a pocket jig. There just is no comparison regarding speed especially if you get an automatic pocket machine.It saves in joint cutting time and doesn't have to sit in clamps, just set it aside and let dry while you do the next frame. Yes if you nail and glue/clamp the frame to the box you have nail holes to fill but the assembly speed more than makes up for it.I was amazed at how much longer biscuits took versus the automatic pocket machine I had been using at the cabinet shop.I think pocket screws have their place, and if the joint is hidden in use then it really doesn't matter how the wood is held together; it seems unlikely that its going to be stressed once its installed. At least in cabinetry, I have yet to use them in furniture and doubt I ever will.For a homeowner or hobbyist the difference isn't such a big deal, but since you are making money I thought I would throw my experience in there and you can do what you want with the information. You could cut your FF time in half, maybe even a third and it sounds like you are doing enough business to justify the investment.Glad to hear your business is steady. Keep it going!
Yea for F/F i use pocket holes..... but for the guy who wants a PC BJ try to find a type one ILO a type II reason being the PC type 1 used a fence design that was pantented by default. PC got sued and had to change the design. So try to find a used one if you can.Buck Construction View Image
Artistry in Carpentry
Pgh, PA
Rich,
I'm with you most of the way here and seem to be the only one here who uses a joint bit when gluing up boards for a table top. It gives me better alignment than biscuits, more glue surface and aligns so well, I glue up all the boards in one shot.
I have to confess though, I do own a PC biscuit joiner and it's a great time saver for those jobs where alignment is necessary, without jeopardizing glue surface.
For fine furniture I agree just for asthetics.But the reality of the situation is I just had a 83" x 24" face frame shoved on diagnonal corners with quite a force and it didn't budge. The piece was actually bowing slightly yet the joints held firm. Still square.Hey I always thought they were a joke and got a biscuit joiner for finish carpentry uses, great for keeping miters closed and level.But I'm sold on their strength.Next time I'll take a photo.<G>N
Edited 2/1/2005 11:47 pm ET by Notrix
Amazing Biscuit Strength!!!
You out to taste my daughters!
a few months ago, I was building a work table for my miter saw on site. I was using 2x material and used biscuits on the aprons and stretchers. one of the guys scoffed at me and said that they (biscuits) were nothing but crap and would have no strength. Any way, I made up a sample joint, using 2 biscuits and glue, clamped it up and set it aside. Next day, I hailed the guy from testerday and challenged him to pull it apart. Well, after he turned red, he took his framing hammer and proceded to beat the two pieces apart. He did seperate the joint, but not where they were joined. the2x4 split about 2 inches away from the joint. During the day I would catch him looking at the sample scratching his head. I use biscuits for a lot of things, on almost a daily basis. Some of the purists out there look down on new fangled ideas, but I guess we use what ever makes our work faster without sacrificing sterngth and quality. I been eyeballin that PC Biscuit jointer for faceframes.
You've described the classic example of the joint strength of wood surfaces mated adequately with adhesive glue.The joint was stronger than the surrounding wood. Happens every time in joints with nothing but long-grain to long-grain contact.The results you describe had nothing to do with the bicuits. In fact, the space they took up in the joint surfaces weakened the joint, and it was still stronger than the wood itself.Rich
Don't ever learn anything new. Rather than give you satisfaction that you know more than you did, it will only confirm you know less than you thought by opening horizons to things of which you had never dreamt and which you now must explore.
But........but.....Norm ( bowing towards Boston ) uses biscuits!!
Actually I do too but usually only to align boards that are going into a table top. It has nothing to do with the strength of the jointWicked Decent Woodworks
(oldest woodworking shop in NH)
Rochester NH
" If the women dont find you handsome, they should at least find you handy........yessa!"
I think a biscuit jointer is a great machine to have around for making a whole flock of utilitarian joints. But there are a lot of folks who like to look down their noses at biscuits.Aside from the Lamello, I would say the PC machine is the best of the lot.
I must concur with you about biscuits. My first experience with them was more than 20 year ago and was initially a sceptic, so I made up a box from 3/4in melamine and filled it with house bricks (about 6 or 7 as I recall) and let it set for a hour. It was then dumped out of the second floor window onto a concrete driveway. Didn't break, so I tried from the third floor - it did eventually break, on the fifth attempt from the third floor, but it was the melamine which broke, not the biscuit joint. I've used them ever since on melamine and MDF but oddly I rarely use them on solid timber....
I reckon that the locking effect of the swelled biscuit combined with the hlding power of modern cross-linked PVA/aliphatic glues makes an acceptably strong joint, even in melamine. Dowels are supposed to have a greater surface area in a joint (if you use enough) but in 20+ years whilst I've never had a biscuit joint on a carcass fail I have seen quite a few failures on dowelled carcasses (I work in a production shop, so we see a lot of carcasses). Perhaps someone could explain that. I also know guys who use building PU glue (the sort that comes in cartridges) in conjunction with pocket hole screws - this works just fine on face frames, but then they don't need much strength.
The main reason why dowels often fail is that they do not really provide much long-grain gluing surface area. Especially when inserted across the grain - only about half the circumference is long grain to long grain, the rest is long grain (in the dowel) to end grain (in the board). So when a horizontal piece (i.e a chair crest-rail) is doweled to a vertical piece (chair leg), the dowels often come loose from the vertical piece, even though they are tight in the horizontal piece.Biscuits make the most of their surface area, because it is all long grain to long grain. (Essentially they are just a short loose tenon.) They don't work miracles, and it is bad practice to rely on the biscuit alone to hold the joint together, but they do work pretty well. They work better than dowels, and are a lot easier to use than dowels, and a biscuit joiner costs a tenth as much as a dowel machine, so it is no wonder biscuits have largely replaced dowels in small shops."Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Essentially they are just a short loose tenon
Exactly!!
I don't understand the "ideological" bias against biscuits. Biscuits are just a quick mechanism for installing short loose tenons. If short loose tenons are appropriate for the joint in question, then why not use them? As another poster noted, they allow more long-grain-to-long-grain contact than dowels, and are alot easier to install. yea, they're not as good as full M&T, but some situations may not need that.
OK, maybe I would rarely use them in heirloom-quality fine woodworking, but alot of woodworking that folks do doesn't fit in that category. I wouldn't put most plywood-carcass cabinetry in the "heirloom" category, for instance.
They are not a "short loose tenon" at all. They are an alignment device. They are very useful in that regard, especially in the environemnt in which they were developed, production furniture assembly. But as an alignment device, they occupy joint space/glue area and in so doing, weaken, not strengthen the joint.Long-grain to long-grain glue joints do not need tenons of any kind, loose or otherwise. Although they certainly may need alignment aids. There are lots of other ways to align boards for gluing. Some are as easy or easier to accomplish. Some a bit more difficult. I think they are all better, and it's a shame that there are a lot of workers now who think that biscuits somehow result in superior glue joints.Rich
I apologize to those that have heard this before. 5+years ago I built a driveway gate. (2) 4' leaves 6' high. Framed each with 2 x 6 RW including 1 diagonal brace. Faced outside with dog-eared red cedar fencing attached with epoxy coated deck screws. Each joint made with 4 #20s and PL polyurethane glue. No other hdwr used except 12" strap hinges, a cane bolt, and a regular dead bolt. No wheels, brackets, Tico plates, cables or turnbuckles what so ever. The tolerance on a dead bolt and its strike plate is less about an 1/8". Last time I went buy that house the gate was 3+ years old and the deadbolt still lined up. Tell me again how biscuits weaken a right angle joint by reducing the glue area. (or how lousy poly urethane glue is for that matter).John O'Connell - JKO Handcrafted Woodworking
The more things change ...
We trained hard, but it seemed that every time we were beginning to form up into teams, we would be reorganized. I was to learn later in life that we tend to meet any new situation by reorganizing; and a wonderful method it can be for creating the illusion of progress while producing confusion, inefficiency, and demoralization.
Petronious Arbiter, 210 BC
They sure look like short loose tenons to me. They do much the same thing as loose tenons do, they just don't do it as well - or take nearly as much time (and skill) to use.
They do not weaken a right-angle joint. Nor, in my experience, do they always weaken a long-grain joint; the CW about the glue joint being stronger than the wood is usually but not always true.
And I want to know which alignment methods are faster and easier to use than biscuits. I can't think of any right now... but it is late, and I should be asleep!"Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Biscuits can strengthen a right angle joint, but not by much. A mortise & tenon, bridle or even lap joint is better by far. Biscuits can never strengthen a (otherwise, correctly-made) long-grain joint.A simpler method of alignment? Cross joint battens and the willingness to use them. For multiple glue-ups of repetitive pieces, can be the fastest and most accurate production line method. For one-off fine furniture, with all the time in the world to spend getting things just so - excellent.Rich
Nobody's arguing that biscuits are stronger than traditional joinery; of course M&T, lap, or bridle joints are stronger. That's not the point. We were comparing them to dowels, weren't we?
I'm arguing that biscuits are, in many cases, strong enough;. Not the best or strongest, but good enough in some applications, where speed matters more than strength. Far better than dowels, anyway. We'll just have to disagree about whether they add strength to a long-grain joint; in my experience, they do.
I'm not sure what you mean by "cross-joint battens and the willingness to use them" as a faster method. Do you mean clamping cauls? Or battens attached to both pieces across the joint? If the latter, I can't see how that would be as fast as biscuits; nor how you would use it on a joint exposed on both sides. Can you clarify?
"Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
Edited 4/1/2005 11:03 am ET by AlbionWood
We're going to run into a little bit of semantics here, but:
Clamping cauls are generally devices ( curved wood members) which spread the clamping forces evenly between clamping points along the length of a joint. Battens are not curved.
Clamping cauls or battens, clamped for instance on the face of a table top glue-up at right angles to the long joints, keep the boards aligned relative to their faces. Of course, all boards must be of equal thickness for this to work best. This in lieu of biscuits to align (not strengthen) the long-grain edge joints.
It's much faster than biscuits, as there is no need to cut the biscuit slots, no need to insert the busicuits and no need to deal with the post-glue-up swelling along the joint at the biscuit positions. This swelling is worse than most people appreciate and requires that the glue joint cure for quite a long time before any cleanup work or surface planing or sanding take place. If surface treatment is done too soon, the swollen areas will be removed and those places will then sink below the surrounding surface as the glue completely dries and cures.
I would not recommend cauls or battens on any right angle joints, as I would be using a joint construction there which is self aligning (M&T, etc) but never biscuits.
Rich
I'm not even sure why we are still arguing - it seems that we agree on almost everything, except you can't admit any possible use for biscuits, and I still see them as appropriate in certain uses.I've read about the "telegraphing effect" but never actually encountered it. Maybe it depends on the wood species and how close to the surface the biscuit is?For me, clamping cauls/battens have always been more trouble than they were worth, but I'll readily concede that is probably just my poor technique (and not enough clamps!). Biscuits don't really work all that well to align warped boards either, though. Going back to the original post that started this off - it was about using biscuits in a face-frame (right-angle joints) and how much stronger they were than expected. If the choice is between biscuits and a M&T joint, and time is a factor, then I think even you would have to admit that biscuits have a place... yes?
"Everything should be made as simple as possible, but no simpler." A. Einstein
http://www.albionworks.net
They sure look like short loose tenons to me too. Although they may often be used as as alignment devices. They fit into slots (mortises) in the pieces to be joined, and serve as the tenons, after a fashion.
I also don't see how they weaken a joint, although I'll agree they are not needed on most long-grain to long-grain joints. They only decrease the direct glue area between the two pieces by the size of the slot, a pretty small area. On the other hard, the glue surface between the biscuit and each piece is double-sided long-grain to long-grain, with a total surface area far in excess of the area which is lost due to the slots. So unless there is scientific test data to the contrary, I don't buy the argument that they decrease joint strength.
I use them mostly for quick FF rail and stile connections, I have the PC unit. That's an end-grain to long-grain joint, so some type of joinery must be used. I think they're better than pocket screws, and alot faster than dowels or "real" M&T.
The few biscuits I have used were from PC, looks like pressed Birch.
How are biscuits made and why do they swell?
The reason I'm asking is because it should be easy to do a few calculations to determine the strength of a biscuit joint, compared to conventional, but what do we use for Youngs modulus and tensile strength? Just the normal values for Birch, or something else?
They are compressed and have a low moisture content. Moisure from the glue will swell your buiscut.
As for youngs modulus, and tensile strength, I'd use lower end values for hardwood in general to be conservative.
This forum post is now archived. Commenting has been disabled