I purchased a FMT from Leigh a few months back - I've been happily
making joints with it since I got it. Very easy to use, and a snap to
get correctly sized moritises and tennons. Usually. Today, I tried to
make 5/16" x 1/2" M&T's. No way, no how can I get these things to fit.
I can get either the width or the thickness correct, but not both. Do
I have a bad guide?

Can someone measure their guide? The dimensions of my guide are 0.700
x 1.161 (measuring at the base, the widest part of the bevel). I'm
also using the Leigh 5/16" bit that came with the jig.

Next up is a phone call to Leigh - I'm sure they'll be able to
determine what the issue is, but since it's the weekend, I thought I'd
ask here.

OK, The measurements on my 1/2" X 5/16" guide are very close to yours. I've
included all of the measurements that I took.

Outside guide = 1.161 X .696 at the bottom edge (your measurement
position - so there's only a few thousandths difference in our readings)
1.090 X .619 at the top edge

Inside Guide = 0.345 X 0.146 at the bottom edge
0.350 X 0.225 at the top edge

I included the readings for both the inside guide and the outside guide
surfaces as the relationship of the two are required to get a good M&T fit.
If all of these readings are close to yours then your problem is not being
caused by the template.

To try to isolate the source of the problem try the following tests;

1. Use the stops to lock the top plate tightly in one position and then make
a mortice and a tenon and then check the fit. If they are OK, then your
problem is likely that the position brake on your top plate is sliping
during the cut whenever you are using the top plate to cut more than one
mortice & tenon position or when cutting a larger M&T than the template
size. This is the problem that I was having.

If the mortice & tenon made in the cut above do not fit OK, then the source
of the problem is somewhere else.

2. Is your router shifting in it's mount? Are you using screws to attach the
router directly to the plate or are you using the rail system to attach the
router. The rails can allow shifting if they are not tightened down really
good. The rails will bend when they are tightened correctly.

3. Are the clamps holding the wood parts tightly so they cannot move during
the cut?

4. Is there any side play in the router shaft bearings or runout in the bit.
Can you feel any side play in the bearings? Can you see any bit runout when
the router is slowing down?

Isolating the source of your problem before you call Leigh will help in
getting it resolved quickly. If it's being caused by their fixture I'm
certain that they will make it right for you. They are great people to deal
with.

If I can help with anything else, you can e-mail me directly or respond
here.

--
Charley


wrote in message
oups.com...
I purchased a FMT from Leigh a few months back - I've been happily
making joints with it since I got it. Very easy to use, and a snap to
get correctly sized moritises and tennons. Usually. Today, I tried to
make 5/16" x 1/2" M&T's. No way, no how can I get these things to fit.
I can get either the width or the thickness correct, but not both. Do
I have a bad guide?

Can someone measure their guide? The dimensions of my guide are 0.700
x 1.161 (measuring at the base, the widest part of the bevel). I'm
also using the Leigh 5/16" bit that came with the jig.

Next up is a phone call to Leigh - I'm sure they'll be able to
determine what the issue is, but since it's the weekend, I thought I'd
ask here.

On Jan 14, 11:44 am, "Charley" wrote:
OK, The measurements on my 1/2" X 5/16" guide are very close to yours. I've
included all of the measurements that I took.

Outside guide = 1.161 X .696 at the bottom edge (your measurement
position - so there's only a few thousandths difference in our readings)
1.090 X .619 at the top edge

Inside Guide = 0.345 X 0.146 at the bottom edge
0.350 X 0.225 at the top edge

I measured the inside guide and got measurements very close to yours.
So, apparently, the guide is not the issue. Not suprising, really.

I included the readings for both the inside guide and the outside guide
surfaces as the relationship of the two are required to get a good M&T fit.
If all of these readings are close to yours then your problem is not being
caused by the template.

To try to isolate the source of the problem try the following tests;

1. Use the stops to lock the top plate tightly in one position and then make
a mortice and a tenon and then check the fit. If they are OK, then your
problem is likely that the position brake on your top plate is sliping
during the cut whenever you are using the top plate to cut more than one
mortice & tenon position or when cutting a larger M&T than the template
size. This is the problem that I was having.

I do the same. The top isn't moving. I've not used this particular
template before, so this was the process of cutting a mortise, cutting
a tennon, and adjusting the depth of the router platform pin. In other
words, I'm not cutting multiple pieces.

Usually, with the use of my digital caliper, this is a one, perhaps two
step process: cut the mortise and tennon, and if they don't fit,
measure the difference in thickness vs. width, divide by two, and
adjust the depth pin accordingly. I usually make the tennon slightly
smaller to allow for the glue.

If the mortice & tenon made in the cut above do not fit OK, then the source
of the problem is somewhere else.

2. Is your router shifting in it's mount? Are you using screws to attach the
router directly to the plate or are you using the rail system to attach the
router. The rails can allow shifting if they are not tightened down really
good. The rails will bend when they are tightened correctly.

This is a good question, one I'll have to check. I have the new
Hitachi router (the funky green Darth Vader one :-) ), and I had to use
the rails to lock it down. It's held pretty tightly, but I'll check
anyway.

3. Are the clamps holding the wood parts tightly so they cannot move during
the cut?

Absolutely.

4. Is there any side play in the router shaft bearings or runout in the bit.
Can you feel any side play in the bearings? Can you see any bit runout when
the router is slowing down?

Nope, brand new router purchased just for this jig. Again,I've used
this same setup to make joints in larger pieces, and the fit has been
perfect, after one round of adjustment.

Isolating the source of your problem before you call Leigh will help in
getting it resolved quickly. If it's being caused by their fixture I'm
certain that they will make it right for you. They are great people to deal
with.

Absolutely, I agree. They've been nothing but helpful with other
problems I've had.

If I can help with anything else, you can e-mail me directly or respond
here.

I appreciate the offer. I'll check out the jig, and report back on
what I find. I'm certain it has to be user error, but trying to
determine what the user error is, especially then the user might be
defective (!), could be tricky :-)

So, I went back into the workshop, and very carefully checked what I
was doing. No go. The workpiece was just large enough to handle a
3/4" wide tennon, so I stepped up to the 5/16" x 3/4" guide, so I did
that. Very quickly, I had perfect joints. Pretty small shoulders, but
that's OK.

I called Leigh today, and after a short conversation with Barry, he
told me that out of all the standard guides for the FMT, the 5/16" x
3/4" guide was incorrectly manufactured. I was the third person to
notice this issue. Ha, I have all the guides, and I just had to pick
the one that was broken :-(

Anyway, they're shipping the corrected guide to me.

Charley, you may want to run a test cut with your guide - if you
haven't used it before, you may find that it doesn't work.

I think you meant to say that the 5/16 X 1/2 guide was the one that was made
incorrectly. You then switched to the 5/16 X 3/4 as a test. Right?

Most of the work that I've used my FMT on so far has been 1/2 inch M&T but I
bought all of the guides for possible future use. I bought the FMT for a
very large project (about 1400 M&T) that I had last year, and then ended up
buying a new router just to finish that project, because the Ryobi RE600
that I had been using was way too heavy and was crippling me. The
replacement, a Dewalt DW618, is about 4 pounds lighter and bolts directly to
the FMT (a big plus). It was a real pleasure to finish the project with the
DW618, which has now become the favorite router in my shop. The RE600 has a
new permanent home, in a router table, where it belongs.

I'm going to test my 5/16 X 1/2 guide this afternoon, and I'll call them for
a new one if it's wrong (I expect that it is, as mine is a year older than
yours). From your discovery, and the fact that they have been shipping FMT's
for several years now, Leigh likely has quite a few of these templates to
replace. Unfortunately, I don't think they have any idea who owns them all
as many were not bought direct from Leigh. Everyone else is going to have to
find out the hard way that they have a problem (or read this thread).

--
Charley


wrote in message
ups.com...
So, I went back into the workshop, and very carefully checked what I
was doing. No go. The workpiece was just large enough to handle a
3/4" wide tennon, so I stepped up to the 5/16" x 3/4" guide, so I did
that. Very quickly, I had perfect joints. Pretty small shoulders, but
that's OK.

I called Leigh today, and after a short conversation with Barry, he
told me that out of all the standard guides for the FMT, the 5/16" x
3/4" guide was incorrectly manufactured. I was the third person to
notice this issue. Ha, I have all the guides, and I just had to pick
the one that was broken :-(

Anyway, they're shipping the corrected guide to me.

Charley, you may want to run a test cut with your guide - if you
haven't used it before, you may find that it doesn't work.

On Jan 15, 2:30 pm, "Charley" wrote:
I think you meant to say that the 5/16 X 1/2 guide was the one that was made
incorrectly. You then switched to the 5/16 X 3/4 as a test. Right?

D'oh, fingers way faster than my brain. Yes, the 1/2" guide was
incorrectly manufactured. The 3/4" guide is fine.

Most of the work that I've used my FMT on so far has been 1/2 inch M&T but I
bought all of the guides for possible future use. I bought the FMT for a
very large project (about 1400 M&T) that I had last year, and then ended up

1400? Good lord....what on earth did you build?

buying a new router just to finish that project, because the Ryobi RE600
that I had been using was way too heavy and was crippling me. The
replacement, a Dewalt DW618, is about 4 pounds lighter and bolts directly to
the FMT (a big plus). It was a real pleasure to finish the project with the
DW618, which has now become the favorite router in my shop. The RE600 has a
new permanent home, in a router table, where it belongs.

The Hitachi is pretty heavy, but man, what a nice router. It doesn't
bolt to the FMT, but it's very, very secure with the rods. I have no
worries. I did look at the Dewalt, but I got a really good deal on the
Hitachi...

I'm going to test my 5/16 X 1/2 guide this afternoon, and I'll call them for
a new one if it's wrong (I expect that it is, as mine is a year older than

Hey, let me know what you find. It was really nice to hear that I
wasn't going crazy this morning when I talked to Leigh.... :-)

yours). From your discovery, and the fact that they have been shipping FMT's
for several years now, Leigh likely has quite a few of these templates to
replace. Unfortunately, I don't think they have any idea who owns them all
as many were not bought direct from Leigh. Everyone else is going to have to
find out the hard way that they have a problem (or read this thread).

Well, that's the beauty (and the curse) of Usenet. Lots of info, you
just have to know how to find it.

Good luck!