Sawing a perfect tenon.

[bobro]

Derek Cohen said:

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Peter Evan (on Wood Central) suggested that it would be helpful in sawing out the mortices for saw handles.

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It seems to me that for production work and specific uses such as a blade mortise, this is a great jig.

Of course those of us who chip our saws from obsidian won't benefit from the magnets.

[Corneel]

I'm afraid I'm going to sit in the field of the detractors. Unless of course you have some kind of a physical problem, it seems to be a bit of a dead end street. By the time you finish making this jig, you could have been a long way on your path to learn to saw a tenon. And I doubt these kinds of jigs help in any way to devellop muscle memory. The only memory is moving your arm back and forth, but the finer points of eye-hand coordination aren't trained at all.

Another disadvantage I think is that it limits the length of the tenon. The fence needs to be quite deep for positive registration, so you are hitting the spine of the saw rather sooner then later. Your demo is with a 3/4" tenon which is really shallow.

But it sure looks ingeneous, and I am sure a lot of people will be happy with it.

[Derek Cohen]

Another disadvantage I think is that it limits the length of the tenon. The fence needs to be quite deep for positive registration, so you are hitting the spine of the saw rather sooner then later. Your demo is with a 3/4" tenon which is really shallow.

That "stretcher" was 2" across and 3/4" wide. I'd say that is pretty average for a drawer frame in a cabinet. You could make a tenon on this guide that is 3 times that size. You could even make a bigger guide! How much larger do you want to go?!

Regards from Perth

Derek

[Corneel]

It looks like not the size of the jig is the limiting factor, but the depth of the sawplate under the spine. It's not rare when I cut tenons almost to the full depth of my tenon saw. The door of the small cabinet I just strated to make will have tenons about 5-6 cm long. Would that be possible with that jig and your saw?

Other long tenons I've made were for example in my dining room table or in the windows for the garden shed. They were probably even longer. Through tenons are another example.

[Derek Cohen]

Corneel said:

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It looks like not the size of the jig is the limiting factor, but the depth of the sawplate under the spine. It's not rare when I cut tenons almost to the full depth of my tenon saw. The door of the small cabinet I just strated to make will have tenons about 5-6 cm long. Would that be possible with that jig and your saw?

Other long tenons I've made were for example in my dining room table or in the windows for the garden shed. They were probably even longer. Through tenons are another example.

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I was using my 14" Gramercy tenon/sash saw as the cheek was only 3/4" long (about average for most tenon cheeks). This has 2.87" depth of cut at the toe and 3.29" of cut at the heel (off TFWW website). However, if I use my 16" Wenzloff tenon saw, I have about 5" depth of cut. That would offer a cheek length of over 3".

To go even deeper, you can use a Japanese saw without a back - once the saw is in an established kerf it is self-jigged.

I don't see why you cannot use a panel saw.

How deep do you want to go?!

Regards from Perth

Derek

[Corneel]

Sure plenty of work arounds.

My tenon saws are about 9 to 10 cm deep. And they are pretty big. I guess the height of your fence is 5 cm. So I loose about half of my tenon saw. Using a panel saw I could imagine that you are loosing registration of the jig after a certain depth? So after that you have to wathc the line again. Well maybe that is a good thing, gets you some practice.

But I am just proposing some possible drawbacks of the design. You as the designer are of course defending the benefits. In the end anyone must decide for themselves how or what,

[MarvW]

Quote:

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Peter Evan (on Wood Central) suggested that it would be helpful in sawing out the mortices for saw handles.

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He probably meant the slot for the blade.

[Derek Cohen]

Corneel said:

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Sure plenty of work arounds.

My tenon saws are about 9 to 10 cm deep. And they are pretty big. I guess the height of your fence is 5 cm. So I loose about half of my tenon saw. Using a panel saw I could imagine that you are loosing registration of the jig after a certain depth? So after that you have to wathc the line again. Well maybe that is a good thing, gets you some practice.

But I am just proposing some possible drawbacks of the design. You as the designer are of course defending the benefits. In the end anyone must decide for themselves how or what,

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Kees, you really are trying hard

You are taking things to ridiculous lengths to make a point - what point ... that a real woodworker should not use jigs or guides? That's just silly. There are so many reasons for using guides with handtools. I could not have built the Wegner chair without them. I am not sure anyone could.

Regards from Perth

Derek

[Derek Cohen]

MarvW said:

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[blockquote]Quote:

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Peter Evan (on Wood Central) suggested that it would be helpful in sawing out the mortices for saw handles.

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He probably meant the slot for the blade.

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[/blockquote]

Marv, quite correct. I should have said "slot".

What do you think of Peter's idea?

Regards from Perth

Derek

[Corneel]

Derek Cohen said:

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Kees, you really are trying hard

You are taking things to ridiculous lengths to make a point - what point ... that a real woodworker should not use jigs or guides? That's just silly. There are so many reasons for using guides with handtools. I could not have built the Wegner chair without them. I am not sure anyone could.

Regards from Perth

Derek

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Ha ha, not rediculous, just basic stuff. Sawing a tenon, how more basic could it be? Efficient handtool use is based on a few things, and skill comes first. Avoiding unneccessary work is another. And choosing materials and designs optimised for handtools. Sawing to a line is a basic skill, not a rediculous one.

So when you want to make a jig to do some basic handsawing, be my guest! But don't be surprised when someone sais Ho hum.

My first objection was that the time spend on building the jig could also have been used to learn a valuable skill that transfers into all other areas of handtool woodworking. I see that cutting depth can be worked around with a panel saw, so that's not so important I guess.

The Wegner chair was a remarkable feat, but it also was an exception.

So, now, don't worry, I'll shut up.

BTW, the reason I chimed in on this thread was your comment about develloping muscle memory when using a jig. I doubt that, but maybe someone with better knowledge about these things could add a comment.