Tennons on the panel saw

[joiner_sim]

Hi all,

I have got to do some mortice & tennon joints. Normally I'd either cut them by hand, bandsaw or using a tennoning machine. However, the bandsaw and tennoner is not an option as my current workplace does not have those machines. Short of doing them by hand, I'm thinking of using the panel saw to do them on. But would like to hear any opinions you may have on the method I am thinking of cutting the tennons in.

The timber will only be about 25x25mm and the riving knife on the saw (I think) doesn't restrict anything going over the top of the blade, only the back end of it. If it does may have to take riving knife off. I hope to achieve a tennon of about 18x18mm. The blade will only be out by 7mm. I will be using the sliding carriage of the saw to hold and cut the tennons. I'm thinking to achieve accurate and repeat tennons, I will use the fence set back away from the blade to set up the shoulder cut. Then I will repeat cuts each time taking the piece away from the fence each time I make a cut. I will do this on all four sides of the tennon.

Does that sound like a safe and accurate way to do this task? I only have about 10 tennons to do, but do want to make a nice job of this, as we don't usually do much bespoke work. And normally its more likley to be a butt joint with the nail gun!

 

[chippy mark]

I have done tenons on the table saw in the way you described without any problem, if you feel comfortable with the method then try it, it takes a long time so now I use a dado blade in a radial arm saw :lol:

 

[Gary]

Do H&S regs allow you to remove the riving knife off?

 

[worsley947]

You are not allowed to take the riving knife or guard off the table saw its against HSE
(hammer) (hammer) (hammer)

 

[joiner_sim]

Health and safety would not allow the riving knife, nor crown guard which is attached to it, to be removed. However now I think about it, I can just move the riving knife and crown guard away from the blade to allow me to do the full cut of the shoulders the tennon safely. Yes the riving knife will have no purpose but technically its not needed in this application and the guard will still be in place to cover the blade.

 

[jasonB]

But if the saw has an overhead SUVA type guard so the riving knife can sit just lower than the crown of the blade it will work safely.

You could also argue that you are cutting a groove or rebate in which case you can remove a crown gaurd as long as the blade is suitably guarded in some other way

Better to cut the sholders on a radial arm or SCMS with trench facility and then do the cheeks on the bandsaw, router table is also quite good for small tennons

Jason

 

[Rknott2007]

Do you have acess to a spindle moulder or router table? Might be a quicker way to make your tennons than removing riving knife and then re- installing it.

 

[Steve Maskery]

My Ultimate Tablesaw Tenon Jig will do what you want safely, accurately, quickly and without breaking any HSE regs. The saw remains fully guarded.
It's simply the best tablesaw tenon jig on the planet.
I admit it's quite a lot to make just for a few tenons, but the results will be perfect and you'll have it for any future projects.
S

 

[Steve Maskery]

You are not allowed to take the ... guard off the table saw its against HSE

That's not strictly true, is it? There are several reasons why you may want to remove the guard. Some perfectly allowing operations can't be done with it.
Of course, I'm not advocating using a saw with no guard, but I often remove my guard AND REPLACE IT WITH SOMETHING MORE SUITABLE FOR THE TASK.
I have several different guards, so any operation I wish to perform can be done safely.

S

 

[woodbloke]

I have several different guards, so any operation I wish to perform can be done safely.

S

Steve, I have no wish to knock your excellent and ultimate tenoning jig (having seen the beast in the flesh) but would removing machine guards contravene current elfn'safey regs within a commercial workplace...doable for sure in a hobbiest 'shop, but in a pro 'shop subject to regs they have to adhere to? - Rob

 

[Steve Maskery]

Rob, show me where it says that guards may not be removed. Machines must be guarded, but that doesn't mean we have to use the guard that comes with the machine. Other guards may do a much better job.
I repeat, my jig is properly guarded.
S

 

[jasonB]

It says for grooving and rebating you can remove the existing provided other suitable guarding is used. You can argue that one side of the tennon is a rebate on the end of a piece of wood.

It does refer to a table that the alternative guard should comply with, which I have not seen.


http://www.hse.gov.uk/pubns/wis16.pdf

If Sim is just going to pivot the front of a riving knife mounted crown guard up vertically to allow the work over the top of the blade then I would have two issues with this

1. Guard not close enough to the blade leaving a large area exposed
2. the work will have to be pulled backwards over the blade after each cut with the risk of kickback

Jason

 

[9fingers]

It works a lot better with a flat top ground (FTG) blade. Doug at cutting solutions got me one recently or you could take a standard ATB blade and get it re-ground by your saw doctor.
I cut virtually all my tenons this way but in a home workshop.

Bob

 

[Chataigner]

It works a lot better with a flat top ground (FTG) blade. Doug at cutting solutions got me one recently or you could take a standard ATB blade and get it re-ground by your saw doctor.
I cut virtually all my tenons this way but in a home workshop.

Bob

Quite so, and an improvised dado cutter using two blades spaced by a couple of washers is even better. You must space the blades by at least as much as the set of the teeth or they will damage each other. I find that using two identical general purpose 24t blades 2.8mm thick, I can space them by up to 4mm, which gives an overall cut of nearly 10mm. Very much faster cutting! It pays to use a zero clearance throat plate or, better still a cross cut sled, to back up the work and prevent chipping from the back edge.

Of course, unless the blades are FTG, the finish will be pretty rough, but a quick pass with a shoulder plane is all that is needed.

This is how I cut almost all my tenons.

 

[9fingers]

The trick to using ganged blades is to ensure that the diameter of the spacer is similar to that of the arbour flanges. Otherwise as the securing nut is tightened, the composite kerf can vary. If you are cutting tenons then this is not much of a problem other than slight distortion of the cheek cut but using ganged blades as an improvised dado and lead to variation in width each time the blades are fitted.

Many woodworkers seem to turn their noses up at stacking blades but with care, I cannot really see a problem.

Bob

 

[joiner_sim]

That is what I'm making. However, the upright is 25x25mm square and it's top is capped off square with a 37x37mm piece. Incase you're wondering what the hell it is... it's a medieval helmet stand! Don't ask! :lol: Anyway, my task has been to make 4 of these. Mortices have been cut into the base and the capping. The base mortice being all the way thru and the capping being a stub.

Today, all joints have been cut. I cut the tennons on the upright using the sliding carriage of the saw. The riving knife did not require any adjustment as it doesn't go all the way over the top of the blade. (It is a custom made one) So machine was correctly guarded. I used the rip fence set back from the blade to give me my shoulder cut, and seeing as I was only taking 3mm off the shoulders of the tennon I was able to cut the shoulder and then just drag the piece across the blade rather than individual cuts. This gave me the 19x19mm tennon required.

I am using european oak and will have it all glued up and finished monday. It's not much of a job really, but first bit of woodwork I've had to do now really for a few months or so! So I'll try and remember to take a picture and attach to this thread once their finished.

 

[joiner_sim]

Thats my finished product.

 

[Digit]

How about some pictures Steve?


Roy.