Dado blade spacer?

Mike Davis

Mike
Corporate Member
Have you ever used a spacer to separate the two sides of a dado set?
What I think I can do is cut both cheeks of a tenon at the same time and have a very consistent tenon thickness.
Then set the dado to the same space and cut the center out for a bridle joint.

I have 80 joints all the same size to cut. What is most efficient ?
 

Hmerkle

Board of Directors, Development Director
Hank
Staff member
Corporate Member
concept seems valid, but you may need to turn the blades around, depending up on the tooth grind..
 

mquan01

Mike
Corporate Member
Have you ever used a spacer to separate the two sides of a dado set?
What I think I can do is cut both cheeks of a tenon at the same time and have a very consistent tenon thickness.
Then set the dado to the same space and cut the center out for a bridle joint.

I have 80 joints all the same size to cut. What is most efficient ?
I have used them for when plywood isnt exactly the size stated
 

tvrgeek

Scott
Corporate Member
I think you would need 4 side blades, not two. I would also be concerned with chip-out. But "gang sawing" is completely valid. Clamped in a fixture of course.
 

pop-pop

Man with many vises
Corporate Member
Methinks a box joint cutter blade set and a spacer would do what you need nicely. Holler if you want me to try for you. Need approximate tenon stock dimensions.
 

Woodmolds

Tony
User
Yes you can do this. You can even make your own spacers with with a good multiply plywood. I have done this before.
I have even used two dado sets with a plywood spacer between to make dentil molding.
 

JNCarr

Joe
Corporate Member
Yes - absolutely works and will give you precise and reproducible dimensions on your tenons.
 

junquecol

Bruce
Senior User
Hello, old cd's make good spacers for fine tuning your cut!!
Playing cards and a 5/8" hole punch also work. A pack of 52 spacers will cost you a buck and a quarter at Dollar Tree, or just a little over two cents per spacer. Many years ago, FWW did an article on doing this, using match ground FTT blades.
 

Martin Roper

Martin
Senior User
I bought a nice set of brass spacers from Woodworker's Supply years ago.

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I can't remember the last time I used them though.
 

Gotcha6

Dennis
Staff member
Corporate Member
If I understand the question, I would think the only caveat would be the length of the blade arbor to accept the spacer. I'd want at least one thread showing through the nut, and then the concern would be that much mass that far away from the support bearing.
 

MTod

Michael
Corporate Member
Yes you can do it. I have done it on a shaper with sliding table. Talked with the former owner of ridge carbide and he opined that there would be no problem. Only thing to note is one side will be less clean of a cut with the outside dado cutters. Keep that to the waste and you will be fine.
 

chris_goris

Chris
Senior User
Sure why not? as long as youre safely on the saw arbor (full nut engagement). Im not sure where you can get a 5/8 ID spacer though, custom made? A fairly large OD would be a "must have" in my book too to support the blades better. Something similar in outside diameter to a blade stiffener at least. The problem you may have with such a thing if made of steel would be the mass, not sure how many HP your saw is. As someone previously mentioned, this is done all the time on shapers. the only caveat is the blades are smaller diameter, I have a bunch in the 6" diameter range, and spacers run I believe are 2 " OD for a 1-1/4" spindle.
 
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mpeele

michael
User
I would not cut the tenon with two blades. I would set the dado for the width plus some of one cheek cut it by burying the dado in a sacaferical fence exposing enough to cut one cheek holding the piece vertical, flip and cut the other side. Then setup dado to cut other side and cut all of them.
 

ssmith

New User
Scott
+1 on use the dado with a sacrificial fence.

Not discounting use of two blades provided you use a spacer with a large enough OD, but it may be more trouble to set up than it's worth. 80 passes vice 160 is a big difference though. Also, I'm not sure what's more important to you - guaranteeing tenon thickness with the spacer, or guaranteeing it's centered with the fence.
 

Mike Davis

Mike
Corporate Member
Yes. I think if this a longer production run the setup time would be less than the run time. I decided to cut with a single blade and I probably wasted some time but I was happy with the results.
 

Charles Lent

Charley
Corporate Member
If you look around some, they also have magnetic shim spacers for DADO blades, which are easier to keep in place. The brass ones tend to get caught in the saw arbor threads and deformed when you tighten the nut. The magnetic ones stay in place on the blade and centered until removed.

The box joint blade sets will give you 1/4" grooves quite accurately. With the proper spacing, they should be capable of cutting the tenons in one pass accurately too, although I've never tried it. I think your biggest problem will be getting the spacer the exact dimension needed. Do you have a tenon jig for your table saw? You are going to need one, or a DIY version with a very fine right/left adjustment, to help you center the tenon.

Charley
 

Mike Davis

Mike
Corporate Member
If you look around some, they also have magnetic shim spacers for DADO blades, which are easier to keep in place. The brass ones tend to get caught in the saw arbor threads and deformed when you tighten the nut. The magnetic ones stay in place on the blade and centered until removed.

The box joint blade sets will give you 1/4" grooves quite accurately. With the proper spacing, they should be capable of cutting the tenons in one pass accurately too, although I've never tried it. I think your biggest problem will be getting the spacer the exact dimension needed. Do you have a tenon jig for your table saw? You are going to need one, or a DIY version with a very fine right/left adjustment, to help you center the tenon.

Charley
I decided to go ahead and cut with a single blade, made three passes. All done and less time than I expected. Yes, I used a tenon jig, all about the adjustments in another thread.

B1AA8E4C-E04E-42A4-965A-901DF26E8B5D.jpeg
 

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