Big crack while creating a mortise

[Luis Reyes]

I'm still new to creating a mortise and tenon but was trying to create a mortise in some red oak. I was halfway through the second mortise when a large crack appeared! I'm kind of bummed to having to start over (not that I was very far yet) but I'm curious what may have caused this?

I hadn't noticed any cracks before starting. I did take the wood from my basement (20ish degrees Celsius) to my garage which was probably around 0 degrees C. But this happened after about 10 minutes.

Hoping to learn what may have happened if it was bad luck or something I may have caught beforehand.

492311


Thanks!

Luis

[Mike Henderson]

I don't know what caused it, but I'd fix it by blowing glue into the crack with an air hose and then clamping it.

Mike

[James Pallas]

Looks like you are cutting parallel to the grain. ?
Jim

[Luis Reyes]

Looks like you are cutting parallel to the grain. ?
Jim

Yes I was, should I cut it perpendicular to the grain?

Could this also be avoided if I had drilled a hole or used a router to have less waste to clear?

[Mike Henderson]

Yes I was, should I cut it perpendicular to the grain?

Could this also be avoided if I had drilled a hole or used a router to have less waste to clear?

Cutting perpendicular to the grain will minimize a split. I always drill out the majority of the waste and then trim with a chisel.

Mike

[Tom M King]

Show a picture of the end grain, and we all may learn something.

[Luis Reyes]

Here’s a shot of the end grain.

@mike. I’m trying to glue it up as you’ve suggested. I don’t have an air compressor but hopefully I got it in most of the crack. 492312

[Christopher Herzog]

I would offer, when working close to the end you may want to clamp the board side to side and support the grain.

Agree with the glue repair suggestion. My dad would say it isnt f'ed up till I can't fix it and I can fix anything. He was old school, vietnam era vet....


Best of luck,
Chris

[Daniel Culotta]

If you were moving your chisel across the grain as you chopped (i.e. you were moving your chisel from bottom to top in the photo) instead of along the grain (i.e. left to right), then you were effectively driving a wedge (the bevel of your chisel) into the long grain of the board, which is how you split wood. It’s a bit counter intuitive, but as you move your chisel along the grain, the cutting edge is actually parallel to the grain, which is what you want.

If you were chopping left to right, disregard.

[Rafael Herrera]

It appears you were cutting the mortise with the edge of the chisel parallel to the grain. Every time you were malleting the chisel you were wedging the chisel between the fibers, it led to the split. Cut the mortise with the edge perpendicular to the direction of the grain.

[Cameron Wood]

Stresses in the wood- not the fault of the mortising- maybe wood selection.

Before cutting to dimension, did you cut a bit off of the end of the board, & see if there was a crack?

[Rob Luter]

It looks like an end check. A normal crack from the drying process. It may have been exposed by the chopping with the grain. As others have suggested, I'd try gluing it up. If it's a crack along the grain the repair will be invisible. It may hold and may not. I've had end checks go both ways. The suggestion of drilling out most of the waste is a good one. Also clamping across the end to reinforce while chopping.

[Tom M King]

The end grain is what I expected. Any time you see grain arcing over like that, the easiest way for it to split is along the radial lines. A lot of such boards are just waiting for exactly the right (wrong) conditions to split there. While these boards may have a desired "cathedral" grain pattern, you have to be extra careful, and even allow for some help for it to avoid splitting. The thicker they are for this grain pattern, the more likely they will split later.

When making wooden shingles, I avoid this grain pattern for this reason.

That's one of the myriad of reasons it's called woodworking, and not just building stuff.

[John Keeton]

I'm with Tom on this one. That much separation in the wood is evidence of internal stress. The chisel work may have been the final straw, but I believe there ultimately would have been a crack anyway. Had it been a crack caused by the chisel, it would have closed after the chisel was removed - visible, but closed. It is possible it can be glued and will hold, but certainly not a guarantee. Worth a try, though.

[William Fretwell]

I’m with Cameron, stress in the wood. If chopping helped released it then the tenon would guarantee that result. Glueing just puts the stress back. Rip the board down the crack, plane edges flat and then glue up. Add some more wood if needed.

[glenn bradley]

I clamp the area if there is a chance of splitting.

492320

Your area would not cause me to clamp the material automatically. It looks like there was plenty of materiel surrounding the cut(???).

[Jim Koepke]

Luis, search on > butterfly keys woodworking < to add a bit to your solution on this if you are going to repair the crack. It can add a distinctive look and help to prevent the crack from reopening.

492325

There are many options on the repair. Please post again to let us know how you proceeded on this project.

jtk

[Luis Reyes]

Thank you all for your comments and suggestions! I'm starting to think there was a small crack and I just didn't pay enough attention to it. I bought this as rough lumber and cleaned it up myself.

I've glued the crack back together and have some additional questions / comments:

1. This is supposed to be the top of a step stool mainly to be used by my young daughter. Should I just mill a new top since chances are the crack may re-appear?
2. Jim, I love the way a bow tie inlay looks! Maybe I should give it a try on this project as I have nothing to lose. Will it still work if I've already glued up the crack?

Luis

[Tony Wilkins]

Thank you all for your comments and suggestions! I'm starting to think there was a small crack and I just didn't pay enough attention to it. I bought this as rough lumber and cleaned it up myself.

I've glued the crack back together and have some additional questions / comments:

1. This is supposed to be the top of a step stool mainly to be used by my young daughter. Should I just mill a new top since chances are the crack may re-appear?
2. Jim, I love the way a bow tie inlay looks! Maybe I should give it a try on this project as I have nothing to lose. Will it still work if I've already glued up the crack?

Luis
I wouldn’t mill a new top unless the crack comes back or you see something else.

[Ben Ellenberger]

You can glue a bow tie in any piece. In fact it you want to close up the crack before you inlay it.

[James Pallas]

I would be cautious about putting a board I knew was prone to cracking into a project that someone may stand on including myself.
Jim

[Rob Luter]

You can glue a bow tie in any piece. In fact it you want to close up the crack before you inlay it.


I would be cautious about putting a board I knew was prone to cracking into a project that someone may stand on including myself.
Jim

If you'd like to salvage the top and assure it's safe but not have a distracting bow tie repair, just do it from the bottom. It will be plenty strong. And to answer your question above, it's fine to add the bowtie after gluing the crack back together.

[Jack Frederick]

I watched a guy repair a windshield crack where the set a vacuum on the inside of the windshield and apply the glue from outside. I’ve since had good luck doing the same with getting glue into a crack.

[Tony Wilkins]

I would be cautious about putting a board I knew was prone to cracking into a project that someone may stand on including myself.
Jim
Would it be repairable/replaceable if he used Hide Glue in the joint? Would it be worth it to try if there was a problem later?

[Mike Henderson]

Thank you all for your comments and suggestions! I'm starting to think there was a small crack and I just didn't pay enough attention to it. I bought this as rough lumber and cleaned it up myself.

I've glued the crack back together and have some additional questions / comments:

1. This is supposed to be the top of a step stool mainly to be used by my young daughter. Should I just mill a new top since chances are the crack may re-appear?
2. Jim, I love the way a bow tie inlay looks! Maybe I should give it a try on this project as I have nothing to lose. Will it still work if I've already glued up the crack?

Luis

I have glued similar situations with good results but to be absolutely safe, use a new board. If you hadn't chopped along the grain, the crack may not have appeared.

Mike

[Daniel Culotta]

I’m assuming James is less worried about repairability and more about the thing failing while someone’s standing on it.

FWIW if you don’t want to use a new board, glueing the crack and putting a butterfly on the underside should make it solid. Sucking glue into the crack with a vacuum or working it in with dental floss are both good methods.

[Luis Reyes]

Thanks all for the tips. I’ll have to try the vacuum or dental floss tip in the future as it had never occurred to me!

I’ve ended up going with two bow ties because I figured i couldn’t make it worse! I’m surprised at how “well” the bow ties turned out as I didn’t think I could do it but after watching a couple of your tube videos I got the confidence and they aren’t ok bad! I feel much better about putting the step stool into use once I do some sanding.

here are some pictures of my bow tie. I did it on the bottom as my wife didn’t like the look on top.

first picture is after glueing then in and the second one is after sawing it down (harder than I thought it would be).

492999493000

[Jim W. White]

I see no evidence of DRILLING OUT the majority of the material before starting to square the hole with a sharp chisel. This step is critical

[Mike Henderson]

first picture is after glueing then in and the second one is after sawing it down (harder than I thought it would be).

492999493000

When I inset something (like those bow ties) I make them just barely thicker than the depth of the area they go into. After the glue sets, I sand them flat.

Mike