FMT Question

[Don L Johnson]

I know it is in the manual, but I haven't figured it out as of yet. At any rate, I'm building a table; the aprons are L x 4" x 3/4". The legs are L x 2 3/4" x 2 3/4", with an offset mortise. The tenon size I am looking for is a width of 3 1/4"; a tenon length of 1 1/2"; and a tenon thickness of 3/8". Of course, a matching mortise.

What combination of bits and joint guides do I need to accomplish the above? Thanks so much!!

Don Johnson
San Antonio, TX

[Jamie Smith]

I don't have a reply, but a question-

How do you like the FMT? It is something that I often drool over, but can never justify...

[Don L Johnson]

Jamie,

I first saw one demonstrated at a wood working show. It made my eyes water, and the desires stuck with me for over a year. Granted, the folks that work the shows are extreme experts.

At any rate, I couldn't justify it either until my wife wanted me to build a dining room table with 8 chairs. All of the mortise and tenon work on the chairs made the decision to pull the trigger a lot easier.

I've only recently started messing around with it and doing some test pieces. What I've seen so far supports the decision to purchase it. Hope this helps.

Don Johnson

[John Durscher]

Don,

I've done this before, but I had to check the manual to remember how. In my copy of the manual (at least in my copy), it is on page 79 under the heading longer and shorter joints. Basically you mess with the centering stops to make it work. It works well, but would be hard for me to explain - don't forget to make the little guard shown on page 80 - I did one without it and messed up. The instructions for this are pretty good. Check it out and let me know if you have any questions and I'll see what I can remember.

Jamie,

I've had an FMT for a few years. I really like it. It does take some fine tuning to get the first joint right, but after that it goes pretty quick. The only problem I ever really had was getting the joint centered exactly where I wanted it. This of course can be blamed on me not paying enough attention, not a fault with the FMT.

However I picked up a Domino earlier this year and that has become my preference for this kind of joinery. It is much quicker to do and I seem to make fewer mistakes with the Domino than I did with the FMT. Although I have managed to find ways to do domino's wrong as well. :D
John

[Dick Sylvan]

Ok, you've got me fooled; what is an FMT?

[Don L Johnson]

Frame Mortise & Tenon Jig, manufactured by Leigh

[Don L Johnson]

John,

Thanks for the input. I also picked up the phone and talked to the tech guy at Leigh...very nice and helpful, by the way. Since I needed/wanted a tenon that was 1 1/2" inches long, "we" decided that the best bet was to go with a 1/2" bit, buy the 1/2" guide set, and reduce the sholder width. His idea was that as long as you have a shoulder, the bigger the tenon the more strength the joint has. In retrospect, that will make the tenon cutting much quicker as well.

On your comment about the Domino being your tool of choice (granted, I don't know much about it), I would think that if one is performing the same exact function many times (chair legs/stringers, e.g.) for many chairs, the FMT should win out; just my thought. Take care, and thanks again.

[Greg Mann]

John,

His idea was that as long as you have a shoulder, the bigger the tenon the more strength the joint has. In retrospect, that will make the tenon cutting much quicker as well.



Don, Some of the recent glue tests seem to contradict this. It appears that the joint failures most often happen at the bottom of the mortice. This would indicate that more wood around the mortice by way of a thinner tenon might be a good thing. Or, put another way, if the tenons aren't breaking, why make them even thicker? Just a thought. Cost? .02