Tip o' the hat to George for mentioning this in my previous insert project!
I have gone through a lot of iterations for a zero clearance insert for my right tilt Delta Unisaw. Oak, melamine, BB plywood, etc.
I made a router template so getting a tight fit to the saw is easy, but they do take time. I have a drawer of about 16 for various blades and saw tilt angles. The BB ply is what I consider the "best" since it has proven tough and can be set perfectly flat with some sanding passes through my drum sander. I wanted to try something even better so I made the 1/2" thick phenolic plate which works perfectly, but I'd still have to make one for each blade type and tilt. Visions in my head made me think of the universal inserts that take a simple insert plate that can be swapped out easily and would be a breeze to make and store. I had some 1/2" aluminum plate which I could shape to fit, but being a bit of a slacker, never quite found my stash of gumption.
For about $100 delivered, the Betterley Tools insert had all the specs I was after for my dreamed of universal base plate. $90 for the insert and $13 for shipping (bubble wrapped in a nice box). This unit is 1/2" aluminum which is fully machined and dead flat, set up for 1/4" replacement inserts of 10" x 2" Betterley also sells these phenolic insert-inserts for about $9 each ($35/4). I'll probably get a batch for my high use needs and make my own for the oddball blades.
Here are some glamor shots and features:
Top side Has the slot for the Delta splitter and thumb hole lift Two spring loaded balls on the side to force it over and take up any wiggle side to side. I might want to tighten it up in some cases and since the "slop" is only 0.020", some thin shim stock or card stock can be jammed in. Also about 0.020" fore/aft movement but no spring ball to restrict it. Also has the rear anti-lift tab machined in:
Underside: Comes with everything needed to install, screws (coated with non-permanent locking compound), and a hex wrench.
The blue sub-insert is also dead flat, but there are holes for adjustment:
Six flat head screws to lock down the blue insert, each with a pair of set screws to set the insert level with the red plate. Set screws in each corner of the red plate as all need them to be flushed with the table. The phenolic insert comes with a relief cut on the underside so the starter cut can be made with a retracted blade:
Fit on the saw shows how the blade aligns, plenty of room for a dado stack:
For use with my box joint blade set, which overhangs the arbor slightly on the left, might require a spacer to clear. I can make my own inserts out of phenolic sheet, which costs about $20 for a 12"x12" sheet, but that'd yield 5 inserts with kerf waste so the Betterley insert replacements with the labor of shaping and drilling provided are not out of line cost wise. If the insert would not be subject to a lot of impact (box joint or dado set), some 1/4" bb plywood should also suffice.
To anyone thinking a Betterly is a good deal, I agree 100%. I don't agree that 35 bux for a 4 pack of the phenolic inserts is though. Essentially you are looking at 0.125 inches or 1/8" thick stock. Yon internet is truly awash in 1/8" phenolic. Just gonna poke Amazoo because a lot of peeps do. You will see for the same 35 bux you can buy a 36 x 24" sheet for the same money, and in case you are not sure if that is a good deal or not it makes a boatload more inserts than 4. All it takes is a wee bit of machining work. BTW Phenolic cuts like a dream on a TS, or BS, routs, and sands super easily, and will hold a shape or an edge easily. I can't imagine how easy it would be to set up a CNC or laser to cut these out. So I say roll yer own, just make sure to use DC, and for Gods sake wear a freakin mask that fits yer face, and you have clean nose holes, and eyes after using it. Buy 3M they cater to the industrial world, where both of those are important. Chinese junk 50 for 5 bux and the "Woodworkers" masks are usually just trash. :-)
My favorite rig, make sure to protect those eyes too.
I'm going to be selling off my General 350, Canadian made, right tilt cab saw. Currently it has a Betterly. Gonna sell that separate. IIRC mine was same cost as what Bruce has in his, I'll sell it to someone for $65.00 with 2 Phenolic inserts. As they are machined aluminum, it's in the same shape as a new one, except a few dings and marks on the finish, but that doesn't affect use. It would be easy enough to use some rattle can spray paint, and make it look all spiffy.
Important!!!!!!! These are designed to fit specific saws, so you would need to have a General 350, Canadian made, right tilt cab saw. Lemme know if you do, and want to get a used, but still good Betterly for your saw.
The inserts on mine are 1/4", but yeah, if you are set up to batch out, a decent piece of phenolic from amazoo (I see one for $20, 12"x12") would work well. Even cheaper by a few $ than the same size in 1/8". They have a bunch of cheap ABS mixed in for really cheap, but based on the ABS pipe I have, it probably would be too soft. Phenolic is stiff as all get-out, but I plan on other materials I already have for most of the ones I need. Acrylic may be good, but not sure on its impact properties.
Just finished setting the insert phenolic level with the aluminum part. There are 12 set screws that need to be set the same as these are what levels the phenolic.
My phenolic measures at 0.247". With the proper gauge.....
It was easy. Just zero out on a flat surface with the phenolic , then with the gauge body on the aluminum carrier, turn the set screw until the gauge reads "0".
Should be, but maybe the aluminum edge near the blade is too close? It could also be something to do with the position of the riving knife, I'm sure an email to Betterley CS probably could answer. Not long ago the SawStops were not super common, now they seem to be everywhere.
I was wondering about how close the blade is to the side of the insert. I've seen really thin blades develop a resonance causing them to sort of wobble as they spin down that might be enough to hit it. Maybe not but would still make me nervous.
--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.
