cutting a tenon in one pass-how to do this

[bsheffer]

I have a Powermatic 66 tablesaw and the Powermatic tenoning jig which is a wonderful 15 lb jig. If you have never seen this jig, it rides in the slot on the tableaw and presents the piece of wood to be cut in a vertical position to the saw top. I have to cut a ton of tenons and I want to do it with one pass. Originally, I thought of taking my forrest dado-set and taking either of the outside 40 tooth blades and some of the 4 tooth stock removal blades and some spacers and building a configuration such that I could take for instance a 3/4 inch piece of stock and essentially remove the outside 1/4 inch on both sides and leaving me with my 1/4 inch tenon. Then I got to thinking about it and it is not a good idea to have the 4 tooth chipper heads exposed to the cutting piece for fear of kickback.
The other issue is that the 40 tooth outside blades of the cutter head set do not leave a perfectly flat bottom as they have an ever so slight "tip" on the cutter blade that supposedly alleviates splintering when crosscutting Dado's..

The question is, how can I configure my tablesaw to be able to cut both sides of a tenon with one pass???

[rwe2156]

I've seen it done with 2 regular blades with a spacer..

The issue you have with the dado blades might not even be noticeable. Try it and see.

[CARYinWA]

If I am reading this correctly you also have to take into consideration the blade on the jig side. You don't want it contacting the metal jig itself so you will need a scrap piece of wood between the jig and the good piece.

[bsheffer]

Yea...I have that sacrificial piece mounted...THe problem is I don't have enough blades if I am thinking correctly, The only real blades out of my dado set I can use are the 1/8th inch outside 40 tooth blades and I for instance, I am trying to end up with a 1/2 inch tenon on a 1.5 inch piece of stock, I need to remove 1/2 inch on both sides which means I need a bunch more cutter blades...I do see where companies make tablesaw blades with 1/4 inch cutter tips but I would need to have at least two of these on both sides and then there is the issue of whether or not they would stack. Without spending a ton of cash, I am not sure I can do what I want to and may just have to make two separate cuts....

[jteneyck]

I don't think the outside corners will be as smooth as if you cut them in the normal way with the stock flat on the table. How much time are you really saving but eliminating that process? But if you want to try it, I'd either use two regular flat tooth ripping blades with a spacer between them, or something like Freud's finger joint blade set. But neither approach will work on stock much greater than 3/4" unless you make the tenon thicker than 1/4".

John

[YSU65]

To do it in one pass the wood would have to be centered exactly or there will be a difference in the shoulders width. This may not be a problem considering your end use. Or you could identify the outside portion of all your boards and make sure this is correctly aligned in your tenon jig. Also if you intend to cut the entire tenon in one pass, there may be some chip out to consider. My experience with the tenon jig is that you can cut a lot of tenons very quickly once it is set up correctly.

[mike4244]

I used 2 new 7-1/4" Piranna blades with a wood disk spacer.
This is not a one pass tenon like you want but does save a small amount of time. You still have to cross cut the depth.So it is actually 3 passes.I used the Piranna blades because they are inexpensive but good quality although they are thin kerf blades.One pass is possible,spacer between dado blades.I have not tried this way myself.
mike

[Splinter Puller]

I do this all the time. It makes for a ton of perfectly matching tenons fast.

I usually use two 7-1/4" blades with various spacers. i've made my own spacers out of aluminum but big washers will work. Use your dado spacers to perfect the fit.

[PaulC]

That ain't ever going to happen. Even if you had the blades and the horsepower (and the intestinal fortitude) to rip 1/2" of material off of each side of a 1/2" spacer for your tenon in one pass; and even if you could get it adjusted right to put the tenon where you want it and end with flat shoulders; Your saw does not have 1 1/2" (plus nut) arbour length to work with.

[JGrout]

Quote:

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Your saw does not have 1 1/2" (plus nut) arbour length to work with.

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not sure where you got the 1 1/2" part at; his hypothetical was for 3/4" stock

I agree with the cut shoulders then trim the faces (cheeks) crowd

It may seem like more work but it is far cleaner (neater) work

If you want to cut both cheeks at the same time use a spacer between two blades of the same size. that takes one pass out of the effort.

Joe