two questions about laminated workbench legs

[Brian Holcombe]

Stressed joints are much more likely to slip over time, or in this case to separate further. Considering the purpose of this glue up I would, at a bare minimum, cut a groove down past the part where it is separating and put a strip of wood in.

Some of the best advantages of hand tools are that you can fine tune a fit up with a hand plane that would be otherwise difficult with machine tools. Even if I am cheating by using a lunchbox planer to get the stock to rough size I will work the remainder of it with hand tools to ensure the surface is flat. You can, of course, do this with a jointer (machine) but it's easier to work the fine end of the spectrum with hand tools.

To to trim the end grain I often do not pare, Instead I will clamp a block, which is perfectly 90 degrees to the area in question and chop it with a mallet while holding the chisel tight to the guide block. A dull chisel will make a mess of this, so it's important to use a sharp one.

Mark with a knife prior to doing this, so that you can use that to start your cut.

[Phil Stone]

Stressed joints are much more likely to slip over time, or in this case to separate further. Considering the purpose of this glue up I would, at a bare minimum, cut a groove down past the part where it is separating and put a strip of wood in.

Hmm, this is the fear that prompted the post. OK, I will consider this. It will be a good lesson in mistake-fixing, at least.

Some of the best advantages of hand tools are that you can fine tune a fit up with a hand plane that would be otherwise difficult with machine tools. Even if I am cheating by using a lunchbox planer to get the stock to rough size I will work the remainder of it with hand tools to ensure the surface is flat. You can, of course, do this with a jointer (machine) but it's easier to work the fine end of the spectrum with hand tools.

I very much want to do my final fitting/surfacing with hand tools, for the very reason you describe (as well as for the joy it will bring me to have this skill). As they say, though, "it takes a bench to build a bench", and I just don't have the work-holding capability right now to joint with a hand plane. I do have access to a shop with a nice jointer and planer, though, so this build has depended very much on machines.

Thanks for your input, Brian.

[Brian Holcombe]

Anytime!

If that is the case, then make sure you are checking for flatness with a ground flat straight edge and winding sticks. It's annoying to do all the time, but will save you a headache or two when doing glue ups.

When you're bench is finished and flattened, you can use the surface as a quick check and that saves a lot of time on smaller pieces. I prefer to check the big stuff with a straight edge and feeler gauges if it is critical. Straight edge and eyeball if it is not.

[Phil Stone]

Anytime!

If that is the case, then make sure you are checking for flatness with a ground flat straight edge and winding sticks. It's annoying to do all the time, but will save you a headache or two when doing glue ups.

When you're bench is finished and flattened, you can use the surface as a quick check and that saves a lot of time on smaller pieces. I prefer to check the big stuff with a straight edge and feeler gauges if it is critical. Straight edge and eyeball if it is not.

I was relying on the jointer infeed table to check for straightness. Either I missed the twist on one of the parts of this joint, or it moved after machining -- this is a risk that comes from having to go out to an external shop to machine, then come back (maybe a day later) to do the glue-up. I should have re-checked for straightness right before gluing.

[Jim Koepke]

I was relying on the jointer infeed table to check for straightness. Either I missed the twist on one of the parts of this joint, or it moved after machining -- this is a risk that comes from having to go out to an external shop to machine, then come back (maybe a day later) to do the glue-up. I should have re-checked for straightness right before gluing.

This is something that occurs in my shop all the time. Most of my projects are made from species of fir/pine. The stuff moves.

Often when cutting dovetail if the joint is not going to be cut and fitted right away, the second half of the joint will not be laid out and cut until there is time to finish the joint.

jtk

[Phil Stone]

This is something that occurs in my shop all the time. Most of my projects are made from species of fir/pine. The stuff moves.

Often when cutting dovetail if the joint is going to be cut and fitted right away, the second half of the joint will not be laid out and cut until there is time to finish the joint.

jtk

Knowing that I wouldn't have time to glue the legs for a day, I dry-clamped all the leg components together when I got them home, hoping this would prevent movement. I also dried the wood pretty thoroughly before machining.

Oh well, best laid plans ganging aft agley, again...

[Shawn Pixley]

1 - Kerf the gap and glue in an appropriate size insert. I think that that needs repair. While the strength for gravity load is largely unaffected, the lateral strength is not there.

2 - Trim the tenons. You can fix the mortise if you want, but it is more difficult.

[Prashun Patel]

Looking at the pic, I think you have to rip and reglue it. If it fails, the mortise will suffer. Beware that this leg will be thinner than the others, so either do the same on all analogs or make sure you recalc your stretcher/rail dimensions.

[Tom Vanzant]

I'd kerf just the separated area and glue in an insert. From the location of the mortise, I'd say the "loose" board is the outer board, so a screw would be very visible. As far as all the mortises having to be identical/interchangeable, no. Treat each joint as unique and individual.

[Phil Stone]

I'd kerf just the separated area and glue in an insert. From the location of the mortise, I'd say the "loose" board is the outer board, so a screw would be very visible.

I'm now leaning towards the kerf/patch solution, due to all the excellent arguments in favor of that approach. My hope is that it will relieve the stress and allow a long, happy and laminated life for this leg.

As far as all the mortises having to be identical/interchangeable, no. Treat each joint as unique and individual.

Thanks. You have uncovered the obsessive-compulsive reasoning behind my wanting to adjust the mortise instead of the tenon. I have now seen the light.

[John Sanford]

The crack doesn't go all the way down. It looks like the left timber's face wasn't flat, which means it doesn't matter how much you try to glue and clamp it together, it's going to separate. Best solution now would likely be to simply cut a kerf using a table saw/circular saw and glue in a plug, or fill it with epoxy.

[Phil Stone]

The crack doesn't go all the way down. It looks like the left timber's face wasn't flat, which means it doesn't matter how much you try to glue and clamp it together, it's going to separate. Best solution now would likely be to simply cut a kerf using a table saw/circular saw and glue in a plug, or fill it with epoxy.

Would epoxy be structurally adequate in this situation? The kerf cut would cut out the wood with Titebond on it, allowing the epoxy to bond, but is epoxy good at this kind of gap filling?

[Jessica Pierce-LaRose]

On smaller sized issues of the same variety, I've used a trick that Tage Frid mentions in his book, kerfing the cut out with a hand saw, and inserting a slice of veneer. If the veneer doesn't fit, you squeeze it a bit in a machinists vise. I wonder if this would work at this scale?

[dan sherman]

Maybe I'm just to anal, but I would saw/plane the entire board off, and then laminate a new one to the remaining three.

[Prashun Patel]

Epoxy is actually great for gap filling. If you go that route, then I would use epoxy to bond the tenon to the mortise in that hole too. If there is epoxy on the wall of the mortise, it will affect the Titebond's adhesion.

It may seem daunting to rip the leg free and re-glue it, but that feels like the simplest and most secure method. It does not require any measuring of the kerf for veneer; it does not require any special glue. In fact, if you rip it clean, the two sides will be self jointing off the blade.

If cosmetics are not a huge issue for you, you could even drive a couple screws into the leg through the seam before you rip it clean. Then remove the screws, rip, apply glue, and use the screws to align the two pieces so they don't squirrel around on you when you clamp. Then you can either plug or leave the holes.