Biscuit Cutter vs Domino

[leehljp]

Can someone tell me their experiences with biscuit cutter joining vs domino joining?

I am contemplating making a rustic heavy table for my daughter and just figuring out what would be best. If it works OK, I will followup with some chairs.

In those situations, what would be better, biscuit cutter or domino.

I have a good biscuit cutter from 20 years ago. I don't have a domino and cannot afford a Festool, but I have seen a few domino cutters - including a DeWalt at fairly reasonable prices.

Your ideas and thoughts?

OH, I have looked at a lot of YouTube and I'm getting to the point that I don't trust most of them. And too many play favorites to their own brand preference.

[capncarl]

Biscuits are for keeping a bunch of boards aligned. That’s about all it’s good for. The reason people build pedestal tables instead of a traditional 4 leg table is because they co not know how to build mortise and tenon style and do not have a Festool Domino machine! A domino is a tenon, which is a structural member. It is a replacement for mortise and tenon jointery. Biscuits can’t do this.
I use dominos in the construction of tables. The domino holds the legs to the aprons very well. To build the slab of the table I also use the smaller dominos , but in this application a biscuit would suffice. Building a cabinet, about any kind of cabinet, a domino machine makes it really fun to build. Forget about the utube plywood boxes. Take a Festool Domino machine and a stack of old lumber and build a real old style piece of furniture!

Concerning the price of a Festool Domino machine. It is a very expensive piece of equipment. I purchased my Domino machine used at a pawn shop 10 years ago for aprox. 1k. I consider this machine one of the most important machines in my shop. If it broke today I would be looking for a way to replace it.

[leehljp]

That is what I needed to hear. Thanks!

[d_meister]

I think it depends on the application. The trouble with biscuits is that the fit is loose enough until they swell that they don't really help align during glue up. After they swell, they'll hold panel glue-ups better as long as the glue lasts because of the tight fit of the swollen biscuits. Loose tenons would be better for chair and table legs because of the extra linear grain structure, but many of the YouTube videos I see of dominoes don't take enough care in setting up their machines to get a tight fit of the dominoes. Perhaps they purposely set them loose for the flow of the video, but if the loose tenons are really "loose", the glue joint won't be as strong over time. They also often don't take enough care in matching domino length to the application, where a very short domino in a chair leg won't provide much additional strength. Plan on someone rocking back onto two legs on a dining-room chair!
I've joined panels made of purple heart with biscuits in the past, and hoped that the biscuits would help align them, but they required surfacing for the very minor misalignment that the biscuits (or my workmanship) allowed. But then, I've had to saw through some of those joints and was impressed with how the biscuit swell eliminated all of the clearance, except for the pockets that were too large because of the depth settings being too deep.

[leehljp]

"but many of the YouTube videos I see of dominoes don't take enough care in setting up their machines to get a tight fit of the dominoes. Perhaps they purposely set them loose for the flow of the video, but if the loose tenons are really "loose", the glue joint won't be as strong over time. "

While I didn't quite understand what I was seeing, that is what I saw that on a few YouTubes - now that you mention it, it is what concerned me the lack of tight fit. And that is why I was thinking that biscuits could do some of the work and maybe all of the work of a domino.

HOWEVER, with the explanations I got from you and Capncarl, one can get tight fits (like a good mortice and tenon) which will be head and shoulders above a biscuit construction. This is a good education to me. Thanks!

[cwsmith]

I agree with 'capncarl'.

I don't own a Domino, though have seen and read of them. Unlike 'capncarl', I have only built a few tables and therefore can't really justify having one. When I built our libraries, for the windo seat areas and the cabinet tops, I bought a biscuit joiner and love it for its ease of aligning boards for that purpose. However, with a 'biscuit' I don't see them as offering significant strength.

For the few workbenchs and tool stands that I have made for things like my router table and radial arm saw, etc. I've used mortice and tenon joints joints.

CWS

[mpc]

I haven't tried Dominos. Festool Domino machines come in two sizes: one for small Dominos and one for large Dominos. The size range overlaps just a small amount... and when I look at the recommended Domino size vs. joint size, I find I need a machine that is between the two. I'd need to buy both to do the type of work I do/envision doing. Not $$ gonna happen. I have an older Freud biscuit joiner which I've used for a few edge glue-ups (tabletop style applications) but I'd be leery of biscuits for structural chair joinery. Unless your chair parts are physically beefy, there isn't space for the larger biscuits. Using two biscuits side-by-side is an option but they would have shallow mortises in the two workpieces which seems like it'd be a strength issue to me. Tenons on chair parts - either formed as part of the workpieces (traditional tenons) or as loose tenons - can go deeper into the workpieces providing more pure mechanical strength before considering whatever additional strength the glue provides.

I've never been a fan of dowel joinery for structural joints as much of the joint ends up as end grain. Picture a dowel hole drilled into vertical grain of a chair leg: the grain is running more-or-less vertically, right? So the 12 o'clock and 6 o'clock positions of the dowel hole will be end grain and thus the glue bond will be weaker. Ergo the use of lots of dowels to compensate. Tenons (regular or loose) have a lot of face area (the faces of the mortises and tenons) relative to the end grain at the mortise ends. Hence tenon joinery works great with glue. A wedged tenon is even stronger: imagine cutting a dovetail shaped mortise (i.e. wider at the end/base of the mortise compared to the entry hole) lots of hand chisel work!) and a tenon with a small slot/split at its end... then, during assembly, you put a short wedge into that slot. As the pieces are put together, that wedge bottoms out in the mortise and thus gets pushed into the slot, flexing/wedging the tenon into a dovetail shape as well. At least in theory when parts are sized properly that joint is mechanically locked!

Rockler's "Beadlock" kit seems to be a solid compromise between Dominos and making traditional mortise & tenon joints. You drill holes in the workpieces as though you were doing dowel joinery, then shift part of the tool slightly and drill more holes that overlap the first. You end up with overlapping holes so the Beadlock tenon has lots of face area for glue. It looks like it would be as strong as any other loose tenon joint including Domino joints... for a lot less $$. I have a Beadlock kit, purchased not long ago when Rockler had a big sale on them but I haven't used it yet to know how well it works. I also bought the Beadlock tenon-making router bit so I can make my own tenons; that way I can make them thicker if needed for tight fitting tenons.

Have you considered making mortises with a router and using loose tenons? A small jig is all it takes to make consistently sized mortises: basically a flat plate with a hole for a router guide bushing, the plate is attached to a fence piece to get consistent spacing. Slipping a shim-like spacer between the fence and the workpiece is enough to offset the jig for making chair rails; the shim provides the setback between the chair rails and the legs. Loose tenon mortises - Domino, Beadlock, router-made - do not have to be centered in the workpieces so one jig could be custom built for chair legs and rails, centering the mortise in the leg ends where that is more important for strength, and then used without change to make un-centered mortises in the chair seat and in the tabletop.

mpc

[capncarl]

Boy this discussion of Dominos vrs biscuits got a lot of involvement!
Using a domino machine will really test your patience! I have probably spent more time reading the instructions and watching U tube videos trying to figure out how to apply the Domino machine to my particular job. Most of the time I cut in a domino at a funny angle . You have to make a lot of mistakes and throw away a perfectly good table leg or whatever, that you have spent many hours milling the wood, tapering 2 sides of the leg and sanded many hours on… because I cut the dominos into the wrong side of the leg. Explanation. I have found that for my Tiny Tables it is better to sand the legs and apron pieces to a ready to apply finish condition before I assemble everything. Thus, ruining a leg or apron requires a lot of work building new components. You can’t get in a big hurry with a domino machine, or any piece of equipment or you will make a cutting mistake and have to start over!

Regarding the Utube videos with loose fitting dominos. The only explanation I can think of is they are making their own domino tenons and are cutting them too small. ( there are router bits sold for the sole purpose of reproducing your own dominos! I have cut my own dominos using table saw cut strips and a router table, but I was not satisfied and will not use home made dominos on important applications. I recently ordered a package of 510 10mm x 50mm dominos from Amazon for aprox $126, thats less than a quarter each. It’s not worth my time making my own. A domino requires quite a bit of force to insert the domino. It’s definitely not a ‘loose” fit. When I build a small size Tiny Table it requires 8 10mm dominos connecting the 4 legs and 4 aprons. Each domino requires tapping in with a 2x2, and the table will stand on it own and can be move around without falling apart before it is dismantled and glued up.

That said, once you learn the in and out of using the Domino machine it is really fast. When I have all of my ducks In a row I can cut every domino in a table in less than 15 minutes! And that includes the 10 minutes I spend getting everything straight in my head. Glueing up and assembly takes longer than cutting the dominos.

[capncarl]

One thing not mentioned. If you haven’t actually held a domino in your hand and studied it, a true domino manufactured by Festool has flutes cut longitudinal on the whole Domino. When coated with glue and tapped into a domino hole coated with glue, this thing is not ever going to come out! Aftermarket dominos that I have personally tried were not fluted but were smooth. When coated with glue and tapped into the glued hole most of the glue gets scraped off, the glue that was coating the inside of the hole gets pushed into the bottom of the hole. The glue in the bottom seemed to prevent the domino from going in deep enough. (The domino machine cuts 1mm deeper than necessary but this excess glue squeezed out is a mess to deal with.)

[leehljp]

It has been 25 years since I last tried dowels but I used fluted dowels then. At my age 78, (79 in less than a month) I really don't want to get into a learning curve as you mentioned. That said, the one area that I still have my most of faculties is the ability so "see" in 3 dimensions. In high school geometry, while most tests took the class the full time, I usually completed in half the time or less. Visualizing constructions and angles have been fairly easy for me, but reading instructions on complicated tools often confuse me! UnRelated: I have 8 grandsons, and ONE grandson has this same ability. We can talk all day on what type of beam or studs are behind a wall or what joinery is probably used on a table or chair.

[capncarl]

Allow me to backpedal on my earlier statement on how difficult and confusing that using the Festool Domino is. Under normal woodworking conditions this machine is easy to use! Most woodworkers probably will not experience the conditions that confused me. I am building small tables with 1 1/2 - 1 1/4” tapered legs that have a double compound miter cut on the top of the leg. This slight angle on the top of the leg does not mesh up consistently with the pin stops on the Domino machine, resulting in irregularities where the leg and apron meet up. This isn’t good if you are striving for perfection! When I build a dining style table with large legs with no angle tops there are no problems. That is the reason that the Festool Domino is one of my most important tool in my shop.

[dbhost]

Biscuits as others mentioned are for alignment, not adding strength. Dominoes are basically loose tenons and add strength. Probably better off with a mortiser / mortising jig and loose tenons without going the expensive and proprietary branded route...

[capncarl]

Even when you get everything right, there are still things that come back to bite you! During several table builds I got everything right, dry fit went perfectly so it’s time for glue and clamps. I like to squirt some glue in the domino hole and smear it around with a q tip, then smear it all over the domino. (I see some people just wiping on some glue with their finger, barely filling up the flutes in the domino and put none in the domino hole. I don’t think that’s enough glue and then how do they keep from getting glue fingerprints all over their woodwork? Anyhow, after I completed the glue up and started the clamping I couldn’t pull out the gap between the aprons and leg! More and more clamp pressure and the gap disappears and glue starts running out of the cracks in the legs. I guess that hydrolocking is really a thing when you have too much glue in the domino hole! Another lesson learned, and I was able to save the table legs.

When I first started making and selling Tiny Tables I was cutting a mortise in the legs and apron ends on a router table and table saw cutting the tennons. This was slow. 20 tables/year x 2 years I was finally able to justify purchasing a domino machine. (In my own mind anyway) I wish I had purchased the domino machine after making my first table using the router table.

A friend of mine builds and sells custom farm house style tables using a kreg jig to attach the legs to the aprons. This looks like a disaster waiting to happen. Profit from one table will pay for a domino 750 machine and speed up his operation and reduce his potential table failure.

[Jim Frye]

FWIW, I used biscuits for joinery since the early 1970s and have had no failures in anything they were used in. All of the table tops and cabinet sides panels I’ve built have stayed just like they were made. I’ve never used dominos, but I see nothing wrong with the concept. I probably wouldn’t use biscuits in a M&T joint even though I’ve seen tests using doubled biscuits where a leg is joined to an apron and it held up nearly as well as a loose tenon joint. I still have the Delta mortising attachment for my drill press, and since I don’t do production work, it fulfills the job for M&T work.