Adding long legs to the Leigh FMT

[Al Navas]

Sometimes a project calls for drastic action. This is exactly what I had to do, to allow me to cut integral tenons on very long rails for a project for a client.I normally work with the Leigh FMT on the workbench. But now I am using the workbench to make a stand that will allow me to set the FMT on this new stand on the bench: A kind of self-raising, tower crane (http://science.howstuffworks.com/tower-crane.htm). I start the process by milling stock for the legs, and all rails. After a couple of test cuts, I am ready to cut the mortises, and then the tenons:

Cutting the mortises:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-mortise-legs.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-mortise-legs.png)

And now, cutting the tenons:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-legs-starting.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-legs-starting.png)

I always dry fit, prior to glue-up. I do it in stages - I like to glue up the legs first:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-legs-dryfit.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-legs-dryfit.png)


Then I glue the rails onto the two sets of legs previously assembled, and check for square:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-glueup-legs.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-glueup-legs.png)


Some tweaking is required - and hand tools are sometimes the quickest way to get it done - thus, the integrated shop:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-tweak-legs.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-tweak-legs.png)


Now I can test the surface mount Leigh clamps on the new plywood top:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-on-legs-3.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-on-legs-3.png)


The self-raising, tower crane-like FMT on its new perch, with a mock-up of a long rail; I must design a cleat to make attachment to the bench a little cleaner:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-on-legs.png (http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-on-legs.png)



This little stand will allow me to cut integral tenons on long work pieces. But I still must figure out a way to better clamp all four corners - I think I will probably use cleats on either side of the stand..




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[Chip Lindley]

As Sir Laurence Olivier asked Dustin Hoffman in Marathon Man, "Eees Eeet SAFE?

The only way you can work atop your workbench is to the side of the jig, which will put you leaning, off-center!! No standing room in front of the jig! Dangling off a step stool or folding ladder to use this particular Leigh jig may be your *downfall*!! Just don't step back to admire your work!!! If the pieces to be tenoned get any longer, you may have to cut a *skylight* in your shop roof!

Seems when a method of work becomes too clumsy or tiresome, another method of cutting mortise/tenons may be a better choice. You may tire of perching up on that bench for a prolonged period of time. Perhaps loose tenons may be the order of the day, cut horizontally?? *WE* are not spring chickens any more!

Be SAFE, and Enjoy another Happy New Year!!

[Richard Wolf]

Nice job Al, good pic also. Yes, that is one of the short comings of the FMT. Maybe a small scaffold to stand on will be next. Good work.

Richard

[Al Navas]

As Sir Laurence Olivier asked Dustin Hoffman in Marathon Man, "Eees Eeet SAFE?

...Seems when a method of work becomes too clumsy or tiresome, another method of cutting mortise/tenons may be a better choice. You may tire of perching up on that bench for a prolonged period of time. Perhaps loose tenons may be the order of the day, cut horizontally?? *WE* are not spring chickens any more!

Be SAFE, and Enjoy another Happy New Year!!

Chip,

I will find a safe way of doing it. A good friend has some old scaffolding he used when he built our shop, and I hope to borrow it or even buy it from him. And I don't want to even think Domino, as I believe the project requires integral tenons. That was the driving force. By the way, another table, just wider than this one for the FMT, flsuh with the bench, might do the trick. And it should take only a couple of hours to make...

Oh, before I forget - NO spring chicken here :D :cool: , that's for sure.






Nice job Al, good pic also. Yes, that is one of the short comings of the FMT. Maybe a small scaffold to stand on will be next. Good work.

Richard


Richard,

Thanks! Scaffolding of some sort. I have thought about using two ladders with something wide between them. But I have not decided yet. My friend's scaffolding might be available - I hope it is. Or, another little table, flush with the surface of the workbench, as I mention above.


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[David DeCristoforo]

"You may tire of perching up on that bench for a prolonged period of time."

What I would do now is install a trapeze over the bench. Then you can hang upside down in front of the jig and rout away.
http://www.daviddecristoforo.com/Misc/rofl.gif

[Al Navas]

David,

Now you throw in a new design issue... it is a never-ending proposition, isn't it? :D


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[Charles Lent]

I had to do this one time several years ago. I clamped my FMT jig to the 2X6 top of the railing of my neighbor's deck (with his permission). It had to face away from me so that the pieces could hang down past the floor of the deck so it was a bit difficult to see to change out the parts. I only had a few tenons to make, so this wasn't too inconvenient.

I had considered cutting a hole in the attic floor of my shop and mounting the FMT on a sawhorse in the attic, before getting permission to use the neighbor's deck railing instead. Either way will work if you don't have too many to do. Fortunately, this is an FMT limitation that I haven't needed to work around more than this one time.

Charley

[Alan DuBoff]

Well, I must say when I first was reading this post I thought to myself, "self, not a bad looking cabinet, even if it is made with a tailed apprentice...". However, seeing what it is used for and that it is NOT a cabinet...I just have to ask...are you really going to work wood up on top of that jungle gym???? :confused:

[Andrew Joiner]

Makes sense to me Al. I have stood on my benches many times over the years. I know OSHA would have required me to wear a harness but I like to live " on the edge".

[Al Navas]

...Either way will work if you don't have too many to do. Fortunately, this is an FMT limitation that I haven't needed to work around more than this one time...
Charley,

I have only a few tenons to cut using this setup. I had to make one other temporary bench, so I might just raise it to be a stage in front of the bench.






...However, seeing what it is used for and that it is NOT a cabinet...I just have to ask...are you really going to work wood up on top of that jungle gym???? :confused:
Alan,

Sure. But not on top of the workbench. Scaffolding was an option, in front of the bench. But now I think that another, temporary table the same height as the bench, will do just fine. Someone suggested the use of a Domino, but that is not an option for this project - integral tenons on very long rails are dictating this setup.






Makes sense to me Al. I have stood on my benches many times over the years. I know OSHA would have required me to wear a harness but I like to live " on the edge".
Andrew,

You are right - safety is always first. And it started with making sure the new FMT support will not tip forward.


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[Alan DuBoff]

Alan,

Sure. But not on top of the workbench. Scaffolding was an option, in front of the bench. But now I think that another, temporary table the same height as the bench, will do just fine. Someone suggested the use of a Domino, but that is not an option for this project - integral tenons on very long rails are dictating this setup.
Al,

Was thinking about this and was curious, can you operate it on it's side, so that the stock will extend parallel to the floor? Or is it possible to invert it and operate it upside down so the stock would stick up?

I'm sure you probably thought about that, but not knowing how an FMT works I just had to ask.:)

One way to secure it better on top of the bench would be to run a board over the top of the stretchers, with a bar/pipe clamp holding each side to the bench (Bessie or similar).

Just be safe when working with a 20,000 rpm router bits, that's the main thing.

[Al Navas]

... Was thinking about this and was curious, can you operate it on it's side, so that the stock will extend parallel to the floor? Or is it possible to invert it and operate it upside down so the stock would stick up?...
Alan,

The FMT relies on gravity. The reason: The router is on a special router base, with pins on its underside; this router base rides on guides inserted into the main body of the FMT. Therefore, turning it on its side, or upside down, is not an option. This photo shows the router mounted on this special base - and the entire router/base assembly on the main body of the FMT:

http://www.leighjigs.com/images/fmt_head1.jpg



... One way to secure it better on top of the bench would be to run a board over the top of the stretchers, with a bar/pipe clamp holding each side to the bench (Bessie or similar)....
I struggled with this one a bit, and considered several options. The problem with clamps on boards on the stretchers is vibration, which tends to result in movement of the table. And at this height it did not feel sturdy enough.

I tried what I now think is the best: Cleats screwed to the sides of the legs; the cleats are then clamped to the bench top. By screwing the cleats to the legs, and all along the side stretchers, it makes for a very stable setup. And the surface mount clamps on the front hold everything tight; on the back I have regular clamps.





... Just be safe when working with a 20,000 rpm router bits, that's the main thing.
Thanks, Alan. To me, safety was paramount, and the reason I tried various clamping arrangements.


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[David DeCristoforo]

...would be to bust a hole in the floor and auger out some dirt. The slip in a casing of some sort and make a cover for it. Then you would have a "morticing pit" and you could do long stock without having to climb up on your workbench. I'm only half joking here.....

[Al Navas]

David,

Now that you mention it... Nah! I might hit the water table if I have to go down that far :D .


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[Paul Johnstone]

"You may tire of perching up on that bench for a prolonged period of time."

What I would do now is install a trapeze over the bench. Then you can hang upside down in front of the jig and rout away.
http://www.daviddecristoforo.com/Misc/rofl.gif

Maybe when you aren't using the FMT, the SWMBO can do a little show for you on the trapeeze. :)

[Alan DuBoff]

The FMT relies on gravity. The reason: The router is on a special router base, with pins on its underside; this router base rides on guides inserted into the main body of the FMT. Therefore, turning it on its side, or upside down, is not an option. This photo shows the router mounted on this special base - and the entire router/base assembly on the main body of the FMT:
I guess the pins pull out if you lift the router???

I see the problem you are faced with. There is no question you can knock out mortises faster on the FMT that I can cut them, although tenons are not difficult, the mortises take me longer doing by hand with a chisel.

And I'm not in any way faulting you for using the FMT, in fact, you have a client and that in itself justifies this unusual fixture. I'm sure you won't be using it all the time, only when you need long stiles/rails. Just be careful!

To me, safety was paramount, and the reason I tried various clamping arrangements.
I've seen that you are normally pretty careful, just the first look at that fixture did kinda give me the willies...you might be able to just stand on top of your bench.

[Al Navas]

I guess the pins pull out if you lift the router???...
Alan,

That is correct. The pins are a part of the FMT router base. One of the pins, the one on the left-hand side of the base, allows adjustment of the fit of the tenons in their mortises. It allows dialing in the fit in 0.001" increments, which is a whole lot more accurate than I cut tenons and mortises by hand. Normally I go for piston fit - and unless you have seen it, it is pretty impressive. The piston fit is the result of having a mortise that is 0.005" wider than the tenon is thick.





... I see the problem you are faced with. There is no question you can knock out mortises faster on the FMT that I can cut them, although tenons are not difficult, the mortises take me longer doing by hand with a chisel...
You are correct, of course. But it is also the look the FMT gives you, Alan. The cut line on the tenons is crisp, and the fit is terrific.





... And I'm not in any way faulting you for using the FMT, in fact, you have a client and that in itself justifies this unusual fixture. I'm sure you won't be using it all the time, only when you need long stiles/rails. Just be careful!...
Correct. I will put the new table to some other use, maybe as an assembly table for the smaller boxes I make - and I will use it at floor level :D .





... I've seen that you are normally pretty careful, just the first look at that fixture did kinda give me the willies...you might be able to just stand on top of your bench.
Standing on the bench is out of the question, as you must be able to maneuver the router on the FMT router base, from the front of the FMT itself. You must be able to use a little target that allows the alignment precision of the FMT.

Thanks for hanging in there with me, Alan. I definitely appreciate your concern for my safety - and THAT is always Number One!

Some additional photos I took today, to show my solution to secure the table to the bench, using the cleats:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-leg-cleats-leftt.png


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[Alan DuBoff]

Thanks for hanging in there with me, Alan. I definitely appreciate your concern for my safety - and THAT is always Number One!
Hey, no problem...thanks for putting up with me! :p

Some additional photos I took today, to show my solution to secure the table to the bench, using the cleats:

http://sandal-woodsblog.com/wp-content/uploads/2008/12/fmt-leg-cleats-leftt.png
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Ok, now I have to say...that looks WAY better and MUCH safer! Even though I know it is pretty high up there, this looks 10x better/safer than what you had.

Ok, I need to get out and do some work...this computer is evil...a terrible time suck...:o