Mortice size for table frame - FMT or morticer?

[woof]

One of my major upcoming projects for 2009 will be a dining table with 100mm legs. To provide the frame/skirting, I was planning to use 54 x 75mm. See below for an initial sketch - but could change of course!

The frame will be made by morticing the 54x75mm into the legs but here's my dilemma. I have a Leigh FMT and just love the control using it to make perfect mortice/tenons. However maximum size I could make is 1/2" x 2" - and if I get a new upcutting bit, could make the mortice 2" deep. Would this be sufficient? Reading around I get the idea that the tenon should be 1/3 width, but the skirting will only be 2" (54mm) wide into the leg? If this is OK, then all I need is to get the special longer Leigh 180cl bit (or a similar I have seen on Wealdentools). If it won't be sufficient, then will need to consider getting a morticer and learn what you professionals do! Thanks in advance for your opinions and advice.
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[MikeG.]

I'm not sure what size M&T's I would use for this.......it depends on where the rails are positioned in relationship to the outer face of the legs........but I am sure that I would pick the joint size to suit the piece of furniture, rather than to suit my tools.

So, have cutting them by hand as an option in your mind.....

BTW, are you sure you want those lower members so close to the ground? You won't be able to vacuum under them, and people will inevitably rest their feet on them........and I would turn at least the 2 short ones through 90 degrees, 'twere it me.

Mike

 

[Benchwayze]

Could you use the Leigh 'Multiple-mortice and tenon' template for this? I think that would cut bigger mortices. Assuming you can still buy these templates that is.

 

[OPJ]

In an ideal situation, your mortises should be cut (first, before the tenons!) to a depth equal to two-thirds the width of your legs (something like 66mm, in your case).

The mortise width (and tenon thickness) should be equal to one-third of the rail thickness. As you appear to have your rails sitting 'the other way', I'd probably make the mortices something like 18x25mm, 66mm deep.

You can also mitre the ends of your tenons for extra length and so they don't interfere with one another inside the legs.

 

[woof]

Could you use the Leigh 'Multiple-mortice and tenon' template for this? I think that would cut bigger mortices. Assuming you can still buy these templates that is.

On the FMT you can do twin and x3 (in triangle pattern) mortices - so twins is a possibility but would it give extra strength?

 

[woof]

I'm not sure what size M&T's I would use for this.......it depends on where the rails are positioned in relationship to the outer face of the legs........but I am sure that I would pick the joint size to suit the piece of furniture, rather than to suit my tools.

So, have cutting them by hand as an option in your mind.....

Yes that is why I am raising the possibility here as to what is best. Just explaining where I am starting from and asking whether the FMT is not designed for the task in hand

BTW, are you sure you want those lower members so close to the ground? You won't be able to vacuum under them, and people will inevitably rest their feet on them........and I would turn at least the 2 short ones through 90 degrees, 'twere it me.


Good point and will adjust for this. Thanks Mike
Mike

Thanks

 

[woof]

In an ideal situation, your mortises should be cut (first, before the tenons!) to a depth equal to two-thirds the width of your legs (something like 66mm, in your case).

Ok so looks like this rules out using the FMT as I believe the deepest upcutting bit only has 2 inch of flute on the spiral. 54mm would be just over 50%. However, I will check out on the Leigh forums to see if this is nonsense I am spouting!


The mortise width (and tenon thickness) should be equal to one-third of the rail thickness. As you appear to have your rails sitting 'the other way', I'd probably make the mortices something like 18x25mm, 66mm deep.

You can also mitre the ends of your tenons for extra length and so they don't interfere with one another inside the legs.

I love this idea - was wondering how to deal with them meeting in the leg.

Thanks OPJ

 

[Benchwayze]

Could you use the Leigh 'Multiple-mortice and tenon' template for this? I think that would cut bigger mortices. Assuming you can still buy these templates that is.

On the FMT you can do twin and x3 (in triangle pattern) mortices - so twins is a possibility but would it give extra strength?

I would think so Woof. It's been some time since I used my multiple M'T template. I did use it for a run of bookcases once, each having three M/T joints, as opposed to dovetails to form the carcasses. No one has so far complained. (I wedged the tenons too btw)