Flat, ATB, TCG, or what for tenons?

[Joe Emenaker]

Here's a dilemma I'm having.

I've only done tenons a few times in my short woodworking life, but, every time I did, they sides (not the shoulder... the sides... the parts that disappear into the mortise) of the tenons would have this very rough texture to them. I'd have to clean them up with a chisel.

It's important to point out here that I was doing these tenons the non-tenonning-jig way, where I just lay the board flat on my crosscut sled and "nibble away", taking multiple passes, moving the board 1/8" each time.

As for the rough result, I had thought that I was just being sloppy... until I saw some dude in a *magazine* with the same problem. So, I knew it wasn't just that I'm a newbie. I still didn't know what the problem was until I was flipping through some catalog and saw some blades for sale and they had a little blurb on the different kinds of blade grinds... and then the lightbulb came on!

On my saws, I checked and found that I was using ATB's. Well, of

*course* that's going to give an uneven surface! So, I started thinking about which grinds *would* work. A TCG wouldn't really work either (at least the ones *I* own won't) because the triple-chipped teeth are set higher than the flat ones.

So, I was thinking that only a flat-ground blade will do. But all of the flat blades I've seen say that they're for "ripping... where speed is more important than smoothness". Well... smoothness is the whole point... and I'm cross-cutting. The only caveat, I guess, is that I'm not cutting all the way through the board.

So, I'm curious as to what y'all have to say about this. I know the "right" anwser is to get a tenonning jig. But, if I'm going to keep doing the "nibble" method for a while, what do you all suggest for a blade.

- Joe

[Bridger]

the cheek.

yep. that'll leave a rough surface....

ummm hmmmm.....

go ahead and try your rip blade. it might work well enough with slow feeds. you could end up with a lot of tearout on the shoulders though. if you do try, post your results, eh?

most good sharpening shops will make you any blade you want. ask them for a flat top negative rake 60 tooth blade with 4 or 8 atb teeth (to clear the shoulders out for ya) and they'll crank one out. prolly be under $200, too.

[Charlie Self]

Bridger responds:

Sure nuff.

Yup. Or nibble slightly over-size and use a chisel to pare down to size.

Charlie Self "A man who carries a cat by the tail learns something he can learn in no other way." Mark Twain

[Anonymous]

[J Pagona aka Y.B.]

Glue surface. That, plus if you picture the serated cheek of the tenon and how it touches the mortise walls, the areas that are glued to the mortise are only supported by short grain.

If I'm just doing a few tenons, I'll nibble them a little thick with my ATB blade (WW2), and then I plane them flat and to size with a shoulder plane.

David

remove the key to email me.

[Larry C in Auburn, WA]

I know you said you don't plan on using a tenoning jig for a while at least, but since others are giving you advice on saw blades I thought I'd give my advice in a different direction. If you buy a new blade just for this purpose you'll probably spend $50-80 which is the price of a decent tenoning jig on sale now at Woodcraft for $60 ($20 off). Or, you can build your own for chump change. You wouldn't have to worry about the nibble marks, don't have to change blades, all for the same cost. It's a thought...

[BruceR]

I had a similar problem. I was cutting some cove moulding using the table saw method where you slide the wood across the blade at a steep angle. I had my WWII installed and while the cut was fast and easy, I had gobs of ridges. The WWII is ATB. My original Delta blade that came with the saw was also ATB, but every third tooth was flat top. Cutting was _much_ smoother! I went in search of a good quality FT grind (ripping blade) and tried that and quality was a little better still. No tear out even though I was effectively cross cutting. I think the key is sharp teeth and a very slow feed rate. Your tennon issue probably would be best solved with a home made tennon jig or aftermarket unit however if you are counting dollars....

-Bruce

[RWM]

I have always use my ripping blade for the operation that you describe. I never have had any problems.

Bob McBreen

[patriarch]

The rough surface you describe is an excellent place to start the fitting process, which of course, is a good excuse to purchase yet another hand plane ;-)

A rabbeting or shoulder plane cleans up what needs to be cleaned up, and will be done with, faster than I can change in the dado blades on the Unisaur. Well, unless we are talking about all 16 tenons on that blanket chest on the bench right now. Don't even talk to me about interrupting one project setup for another, with higher priority.

But seriously, there always seems to be SOME tweaking to be done, and the fine tools from Robin Lee's Canadian handplane emporium make it seem more like wordworking.

Patriarch

[Robert Bonomi]

Answering the "question, as asked", an ATBR blade comes closest to the cut you're looking for.

If you're worried about tear-out, use your cross-cut blade and cut the line _at_the_shoulder_ *first*. Then change blades and nibble the rest away.

That said, a basic tenonning jig is _trivial_ to make. A quarter-sheet of ply, a few feet of 2x2 (2' necessary, another 3 is optional), and a chunk of 'something' to ride in the miter slot. Also 4 (circa) 3" bolts w/ nuts, and

8 fender washers.