Timber variation & Mortise/Tenon runs

[LancsRick]

A theoretical question here as I've been doing some reading tonight to improve my theory understanding of all things joint-related. The M&T has been around forever, and I've made a few in the past for windows etc, but never many, and always by hand, marking up "best face" and measuring each M&T as a unique thing to ensure alignment.

I assume that the above approach isn't what is done if you're doing (e.g.) a piece of storage furniture with lots of M&T joints. Do you thickness all the stock so you know it's all identical and then do a router jig/table saw production run for the mortises and tenons? Or is there something else I'm not considering?

Cheers.

 

[custard]

If you've got a lot to do then you don't mark them out individually, you lay one out for the purposes of setting up the machinery and checking everything's been done accurately, then you just bang through them relying on stops and spacers instead of manual layout for the joinery, and relying on your dimension saw and planer/thicknesser to produce square and true components.

There's not much romance in series furniture production!

 

[LancsRick]

Figured as much, cheers. With the variation in most timber sold as PAR, I assume everything gets thicknessed by you so you have confidence in the consistency of the raw material?

 

[custard]

Figured as much, cheers. With the variation in most timber sold as PAR, I assume everything gets thicknessed by you so you have confidence in the consistency of the raw material?

Exactly right. Furthermore you try not to hang around after machining the components square. It usually gets jointed, assembled, and cramped up before the timber has a chance to start misbehaving!

 

[LancsRick]

There may not be much romance in that but it means I can indulge my love of creating jigs at least!

 

[RobinBHM]

The key is to always work from 1 datum face.

In joinery one tends to work moulding face down on the spindle moulder, so if thats the way you want work also make sure the morticing and tenoning is worked from the same face.

Any variation in timber thickness wont affect accuracy, but will mean joints will be flush on the moulding side but stepped on the other face.

 

[Steve Maskery]

Rick
Am I right in thinking that you have recently bought my DVDs? If so, watch WE3 for an (excellent, in my opinion!) explanation of why so many tenon jigs are flawed in their design. As Robin says, all cuts should reference off just one face, just as you would if using a mortice gauge and hand tools. Any technique, with hand tools, a TS jig or a bandsaw or BS jig, that requires you to turn the workpiece over for that second cut is inherently less accurate. It's even more vital if doing something like a double tenon.

Here's one I made recently:

That kind of accuracy and precision is only possible by having a common reference position.

The other advantage of having a single reference face is that you can cut your tenon off-centre if you want to, rather than being forced to have it dead centre, which is what happens if you use a turn-it-over technique. This is handy if you are making a delicate table, say, where the legs are slender. You can offset the tonons closer to the outside in order to maximise their length in a very small volume of space.

 

[LancsRick]

Afraid that's not me Steve. I'm learning in a somewhat haphazard order as it's down to what projects I'm doing at any given time and my small workshop. As always, the advice I get on here is fantastic. Cheers!

 

[Brentingby]

Afraid that's not me Steve. I'm learning in a somewhat haphazard order as it's down to what projects I'm doing at any given time and my small workshop. As always, the advice I get on here is fantastic. Cheers!

You should get Steve's DVDs since you're a jig-aholic and since Steve's mortising and tenoning jigs elegantly deal with exactly what you are thinking about here.

I'm looking forward to his next video, The Ultimate Tablesaw Mortise Jig. :lol: :mrgreen:

 

[LancsRick]

I will have a look then

 

[Steve Maskery]

I'm looking forward to his next video, The Ultimate Tablesaw Mortise Jig. :lol: :mrgreen:

Now that is a jig too far, even for me!