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Mortise Pal alaignment

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Forum topic by Laughran posted 12-31-2015 12:32 PM 544 views 1 time favorited 11 replies Add to Favorites Watch
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Laughran

65 posts in 1393 days


12-31-2015 12:32 PM

I bought a Mortise Pal just before they went out of business and have used it a handful of times. The problem I have with it is getting the mortises to perfectly line up so that when the tenons are installed my face frames line up. The face frames are always off line a tiny bit and I end up making the adjusting the tenons to get things it line up. So my question is, do your mortises always line up so that you can fit a full size tenon, or do you make your tenons smaller so that you have some adjustment?

-- David


11 replies so far

View Fred Hargis's profile

Fred Hargis

3942 posts in 1958 days


#1 posted 12-31-2015 12:38 PM

There is a limit as to how much smaller your tenons can be, I wouldn’t approach it that way. Are you referencing off the same face with your jig? That is, always put the clamp screw on the inside (or outside) face when you cut your mortises. I’m guessing the stock is all the same thickness as well. The last thing to check is your router, if the bushing isn’t centered precisely, you will get the results you mention. there are a number of aids to help center the bushing available from various places…if you think that’s the problem check back to find everyone’s favorite.

-- Our village hasn't lost it's idiot, he was elected to congress.

View sawdustdad's profile

sawdustdad

131 posts in 350 days


#2 posted 12-31-2015 12:42 PM

You can’t adjust the frame alignment by making the tenons smaller—they should not be loose in the mortise. Some misalignment is inevitable—the challenge is to make is so small that it’s not an issue or, worst case, can be sanded or scraped/planed away.

Usually, you should make the mortises first, then cut the tenons to fit. To keep the mortises centered on the stiles, cut the mortise from one side, then turn it around and cut it again from the other side so any off-center variance is removed. That assures your mortises are centered, even if they are a little “oversized” as a result. Then, with all the mortises cut, go to the TS and cut the tenons to fit, again, cutting the tenons by flipping the rails over and cutting the tenons so they are always centered.

-- Murphy's Carpentry Corollary #3: Any board cut to length has a 50% probability of being too short.

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bearkatwood

1205 posts in 476 days


#3 posted 12-31-2015 12:46 PM

I have not used the mortise pal, but I can tell you I have a Trend jig and it has the same issue of set up. What I have found when I use it, that I need to really slow down and try to get as accurate as I can and a test piece is a great way to check for square. Just mill up some short pine of the same thickness and use that to make an extra tenon and then again when you set up the mortise. If your fit is off you can adjust accordingly. Hope that helps.

-- Brian Noel

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Laughran

65 posts in 1393 days


#4 posted 12-31-2015 12:57 PM

I always do reference the same face and the stock is all the same thickness and I always check that the bushing is centered. Just to clarify the faces of the boards line up perfectly, but the stile and rail does not line up on the bottom, so I adjust the height , not the width or length of the tenon to get the bottom edge to align.

-- David

View Fred Hargis's profile

Fred Hargis

3942 posts in 1958 days


#5 posted 12-31-2015 01:17 PM

I think that’s OK to do, and in fact a Domino has the ability to widen the mortise slightly…which I’m guessing is for the misalignment across the height. As long as your cheeks are snug you’ll get a strong joint.

-- Our village hasn't lost it's idiot, he was elected to congress.

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AandCstyle

2572 posts in 1722 days


#6 posted 01-01-2016 01:13 AM

David, if the stiles and rails aren’t meeting at the top and/or bottom, it might be your center lines are off. I set a marking gauge or a try square to the desired length and mark everything without changing the gauge until I have everything marked. If you are doing that, then the only other source of error that I can think of right now is that you aren’t getting the MP properly aligned on the marks. HTH

P.S. I just thought of a couple additional possibilities: Are your tenons full width (not thickness) of the mortises? if they have any play, that could allow the rails to shift a bit. Do you sand the rails before dry fitting? That might create a 1/32” mis-alignment or so.

-- Art

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Laughran

65 posts in 1393 days


#7 posted 01-02-2016 12:23 PM

Thanks for all the suggestions
Art, I use a inca marking gauge and I am very careful with my layout lines to make sure that they are consistent
I will say that the centerline indicator on the Mortise Pal is not that easy for me to see, but I do take time to align the indicator with my layout marks.
Every joint I do will be a bit off, maybe only 1/32 and I trim the tenon to get things to line up.
Do your joints always line up or do you have to adjust sometimes?

-- David

View lj61673's profile

lj61673

259 posts in 1864 days


#8 posted 01-02-2016 01:09 PM

Laugran,

Sounds like you may have wood chips in the mortise preventing the router from reaching the ends of the cut and leaving the mortise short. I have had this happen to me. Always make a full plunge at each end of the mortise before cleaning out the center in multiple steps. This way there is no chance of a small shoulder at the bottom of one or both of the end cuts.
Hope I explained that clearly.

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Laughran

65 posts in 1393 days


#9 posted 01-02-2016 01:44 PM

Ij61673 I do plunge at both ends and then clean out the rest, my problem has to be in aligning the centerline indicator with my layout lines. I’m going to try putting a little white paint on the indicator to see if that helps

-- David

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AandCstyle

2572 posts in 1722 days


#10 posted 01-03-2016 12:11 AM


Do your joints always line up or do you have to adjust sometimes?

- Laughran

All my joints are always perfect. That’s my story and I’m sticking to it. And if you believe that, I have a bridge I would like to sell you. haha

That said, I have a handy little block plane that sometimes helps to improve on perfection.

-- Art

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HarveyM

92 posts in 1487 days


#11 posted 01-03-2016 12:50 AM

I find the Lee Valley Magnifying Bench Lamp helps aligning my leigh FMT mortice & tenons. I use digital calipers to measure the workpiece and a marking knife to scribe my lines. I also reference off of both faces- if I’m truly centred, there’ll be a single resulting line.

-- Just a Duffer

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