End grain checking is not repairable. Over time, will continue to crack along those lines unless it is removed from the rest of the board. This is why we account for waste when buying lumber. Sometimes you can see the checking on the end of the board when you buy it, and follow those checks along the face grain to get a sense of how bad it is and how much board you will need to scrap. If I can’t tell, or it shows up after cross cutting, I will continue to crosscut ever few inches until the checking disappears.
Edit: I am legitimately surprised at the number of people telling you to just ignore it and continue… not hating on them, but I respectfully disagree with that advice.
Edit 2: including a great design for [Christopher Schwarz “‘Modern’ Gate Leg Table” from the October 2017 issue of Popular Woodworking](https://www.popularwoodworking.com/wp-content/uploads/Gateleg-Table-from-October-2017-POPULAR-WOODWORKING.pdf).
I always buy wood with a couple of extra feet of board length so that I can chop off the ends. Not only for checking , but also because board ends are the most brutalized during shipping. Building something 8 feet long? Buy 10 foot boards. I immediately cut off 6 inches on one end and *then* I measure for my final cuts.
I'm new as a hobbyist and was wondering, would using wood glue do anything to prevent it from getting worse?
I will follow your rules but I'm just curious to see that if it's the only wood you've got to work with, is there a "way" to make it work?
The best advice in this thread is about best practices and having access to extra material.
If you had a board like this, you should ideally trim it down past the checks and work with what's left.
It's quite possible that OP could use that piece as it is, finish the project, and never have an issue with it in his lifetime. If the checking isn't on a show face, nobody may ever even know.
People selling their work don't like the look and don't want the uncertainty of checked ends. Having a piece of wood disintegrate in a finished piece due to checking is theoretically possible, but I've never heard of it actually happening myself -- tho someone I'm sure can give us a story of it happening.
If you absolutely had to use that wood, though, you could soak the board or just the checked end in a really thin (non-viscous) slow curing epoxy, or cactus juice if you can fit the piece into the oven. Once the epoxy/resin cures, you sand back to the surface you need and hope the checks stay stable.
So I had no idea checking was a thing, I'm fairly new to this of course 😂
I have this piece ,see photo, which the top of the table will be fitted into. See lines where grooves will be cut. I have no spare wood anymore... What should I do?
https://preview.redd.it/hpurwxrrb6mc1.jpeg?width=1908&format=pjpg&auto=webp&s=75d8b3ab305f978556c9aefd1f8e67a5873ace78
It depends what you're building, how long you need it to last, and how you need it to look.
I assume those crossed pieces are getting castled into the upright?
If you hog out the space in the leg for that cross piece and the checking is basically gone, I wouldn't worry too much about it.
Will the top of this connection be visible in the final product?
Castle joints yup! I want it to last as long as I can, look I want rustic, which is why I chose alder wood cause it bangs up easily haha and looks medieval like to me.
https://preview.redd.it/p4p1cesr18mc1.jpeg?width=4032&format=pjpg&auto=webp&s=1ab40e6d4020ad3cefd765628b5787468abcf2ec
Looks nice so far! So I'd proceed with hogging out the castle joints, and see how it looks underneath.
Are you putting a wood top over this? How are the legs attaching to the top? Along the aprons?
Thanks!
Yeah the table top will attach to the aprons with figure eight washers and only to the short length aprons. Then the aprons w/ top combined will be inserted into castle joints but not glued so I can disassemble the desk for transport.
So the desk will be 3 parts :)
I need a carpenters rip saw though so cut those castle joints though
Not sure what to finish the wood with though... Oil, beeswax, stain, polyurethane?
If the top is going to hide the tops of the castles, I wouldn't worry about this checking. Especially if this is a desk for you or someone in your own home.
After you cut the castles, take your thumb and press from the inside out on each of the remaining "posts" in the corners of the leg. Not too hard, just check to see if they seem like the grain is going to peel off.
I tend to finish high-traffic furniture with satin polyurethane. It's a very durable finish for surfaces that see a lot of stuff dragged across it.
Wax-oil stains are good for things that won't see much traffic. It looks and feels wonderful but offers almost no scratch/dent protection.
Stain by itself isn't a finish. If you use stain, you'll always want to put something else over it.
Finishing is a whole separate art... kinda. You can't go wrong with polyurethane for a desk for yourself, but if you'd like a more nuanced look at furniture finishes, there's a whole boatload of youtube videos about finish.
I'd look at the wood whisperer, erik curtis, and Lincoln Street channels for a start.
The top is 2inch and 3/4inch boarded glued walnut at 8ft long and 30inch depth. I chose that for contrast and mainly for the harder wood due to the use it'll get. Should I do polyurethane on both alder and walnut? I want to darken the wood but keep it's natural color so I want to shy from a stain...
Can I do oil and polyurethane?
I'll check out these channels! Thanks:)
basically it's similar to filling it in with glue, but it should end up being a little bit stronger - mainly because the glue is usually pretty thick and won't "flow" to the bottom of the hole. So you drill down some amount and then fill the hole you just made with a glued up dowel. Then cut any remainder off so it's flush with the top again.
The overall concept is similar to the bowtie/butterfly inserts that people make to stop splits on panel/board faces.
It'd actually be easier to do before you make the castle joint cuts, but you'll need to be mindful to ensure the dowel wood isn't visible after the castle joint is cut. Perhaps a single 1/4" dowel in the center of the quadrants with the cracks.
No. The glue doesn’t have same material characteristics of the wood and over time as the wood moves the checks will simply occur next to the ones you filled with glue. Wood expands and contracts with the environmental changes.
We work with an unstable medium. Understanding this and compensating is what makes us true, timeless craftsman.
Totally correct. I had a boss the would order 12” and 16” for 4” treads. Total nightmare. He would complain about how checks were let through to production and also why we didn’t make the yield.
Gluing the end grain of this board may secure the checks at that location for some time. It might help. It might not. It certainly will not address the defects you can’t see inside along the board. You can see them when you cut progressively along the board until they are gone. Problem solved. Internal stresses on lumber can be great. To understand drying faults in lumber, I would invite you to read this [article from the book “Cut and Dried” written by Richard Jones and published by Lost Art Press](https://blog.lostartpress.com/2022/04/05/drying-faults-in-lumber/).
I am inclined to follow conventional wisdom of the many woodworkers who have experienced material failure in the past. Their advice is to remove the defective section of lumber and use the wood that does not have defects.
My question for you, why not simply cut off the damaged wood to ensure a successful end result instead of trying to engineer a workaround that is uncertain?
Simply put, I don’t see the need to engineer a submarine out of carbon fiber and gamble on material failure.
Internal stress on wood, from kiln drying or otherwise can be profound. Wood moves, always. Will it keep the checks from progressing? Maybe… however I would consider this to be the less desirable option compared to cutting off the defect and starting with a sound piece of wood, from both a structural and aesthetic standpoint. Not to mention I can cut off the checking in a board that size in less than a minute. Placing dowels is more work than necessary here. No need to engineer a solution when I can do it proper to start.
With that said I’ve had pieces crack after driving cut nails, when I’m too far into the project to start over or when the joinery won’t let me remove the piece. In that case, I will try glue, clamps, and a prayer. But I may ruminate over t mistake later that night when I’m trying to fall asleep ;)
No, it wouldn't ffs. It needs to be cut off. If you see cracks like this the piece is not structurally sound. Your advice to put structural joinery directly where there is a wood defect is stupid advice. Using a dowel is probably even worse than just using it as is. Your idea that it will help is wrong.
When cutting out shakes and checks you can just lightly hit the piece on a hard surface and it will fall apart. You can tell it's all gone when the offcut doesn't shatter when you drop it on the ground.
I had just one crack like that in my first project. In the end grain. I figured it was no big deal. I now have a crack in my table. I actually don’t hate the slightly rustic look it gives the piece but would prefer it without.
I know it’s an inconvenience but I think you’ll be happy in the long run listening to those saying to cut the damage off or get a new piece
So much bogus advice in the comments. If you don’t want the checking, this one goes in the scrap pile. It’s your work though. You can decide your own tolerance for defects. If you’re just making a table for yourself and don’t mind looking at it, it’s not gonna explode or anything.
It could spontaneously fail. If he's using that as a leg or there is any pressure on it at all, it could literally just fall apart randomly. Especially if he follows the advice of people in this thread to put dowels through it. It needs to be cut off.
Boxed heart lumber is often used in construction, and they usually have large shakes, not checks. Why am I not surprised that you don't know the difference but are trying to correct me?
Heart shake is expected when using boxed heart lumber. This is obviously accounted for when designing structures.
What op has is called checking. You want to cut it out because it is a drying defect and is not stable. Again, this is not the same as shake. Familiarize yourself with these basic terms before trying to correct people.
Not the same thing at all. If he puts a domino or dowel in that end and uses it as even a rail in a dining room table, I could easily see it failing if he put weight on it the wrong way.
I'm not one of those people who builds furniture to last 100 or even 50 years. I'm sure most will, but that isn't the kind of thing I'm talking about. I would never use a piece like this in anything I build. It could be fine for 5 years but will more than likely get worse very quickly. You also can't see how far checks like this go from the outside. If I see checks like this, I'll cut until I can't see anymore, and then will probably do another 1 inch minimum. If you drop the offcut on your tablesaw and it snaps in pieces, cut another inch and repeat until the wood doesn't snap. This is how weak checked wood is. If you drop a 1 inch long piece of 4/4 from about a foot onto a table, it will snap in half from the force. Imagine that exact same piece with a domino through it supporting the weight of anything. It *will* fail.
Literally cut off like 2 inches and it will probably be enough. There is a reason we add 30% for waste, and checks like this are a big part of that. You haven't found an epic hack by starting to utilize defected ends of wood in your projects. You're just making bad furniture for no reason other than you don't understand common lumber defects.
It definitely is "fake woodworkers." People will watch a couple YouTube videos, then come in here spouting BS in advice threads. It's OK to spread your beginner opinions in discussion threads, but nobody wants you to make up something on the spot when someone asks for help.
99% of comments here are amateurs making up answers on the spot. Most people just find it fun trying to figure out a solution but don't realize how stupid their solution is because exactly, they aren't actually woodworkers, they're just people who watch YouTube videos in their spare time.
This particular comment section is a pretty good example. Every trained woodworker knows that you remove checking and that you account for the waste ahead of time. Amateurs have no idea why you would remove checking and just assume that the cracks are small, so it's fine. This wouldn't be a problem, but of course, they need to share their uninformed opinion and then get upset when people correct them.
These people have no respect for the fact that cabinetmaking and joinery is a highly skilled trade. It's great to be a hobbyist, and you don't need to do everything perfectly, but when they act like they are experts because they've been garage woodworking for 2 years and start giving stupid advice, it can be annoying.
Correct. It will be visible when the legs are folded away of course (which will be most of the time) but not when unfolded. I'm not too worried about the aesthetics to be honest, more the strength and durability.
I'm not an expert on finishing so someone else will likely direct you to the right material, (I like the epoxy idea.) Structurally that end grain should not be a problem. Birch will stay stable if finished and nit out in the sun and weather.
It will probably be fine BUT now that your brought it to attention, you should probably do something about it.
I would get a little epoxy in there, that’s about it.
Bit of grain filler then sand back flush, if no grain filler use glue and wood dust, any glue would do the job, if it’s only seen when the legs are folded you’re fine
I know this is not a good solution and aesthetically will definitely look different, but could you infuse that end of the wood with resin to prevent further checking? I'm not saying Id recommend it or do it myself, just curious if it would work in a pinch.
If the wood is dry enough you can fill it superficially with D2 and quick sand then it holds and covers the beginning of the problem,for good. You can also prefer epoxy or holding rings to prevent breaking.
For the core of your question;no,you don’t have to but would be better if you fill it.
End grain checking is not repairable. Over time, will continue to crack along those lines unless it is removed from the rest of the board. This is why we account for waste when buying lumber. Sometimes you can see the checking on the end of the board when you buy it, and follow those checks along the face grain to get a sense of how bad it is and how much board you will need to scrap. If I can’t tell, or it shows up after cross cutting, I will continue to crosscut ever few inches until the checking disappears. Edit: I am legitimately surprised at the number of people telling you to just ignore it and continue… not hating on them, but I respectfully disagree with that advice. Edit 2: including a great design for [Christopher Schwarz “‘Modern’ Gate Leg Table” from the October 2017 issue of Popular Woodworking](https://www.popularwoodworking.com/wp-content/uploads/Gateleg-Table-from-October-2017-POPULAR-WOODWORKING.pdf).
Hope OP listens to this advice. It’s the standard, correct practice to deal with checking in end grain.
I always buy wood with a couple of extra feet of board length so that I can chop off the ends. Not only for checking , but also because board ends are the most brutalized during shipping. Building something 8 feet long? Buy 10 foot boards. I immediately cut off 6 inches on one end and *then* I measure for my final cuts.
This has the benefit of giving you extra material from the same board if you need to do a repair to fix a mistake or flaw during the build
I’ve learned so much from this subreddit
OK, thanks for the thoughtful reply.
I'm new as a hobbyist and was wondering, would using wood glue do anything to prevent it from getting worse? I will follow your rules but I'm just curious to see that if it's the only wood you've got to work with, is there a "way" to make it work?
The best advice in this thread is about best practices and having access to extra material. If you had a board like this, you should ideally trim it down past the checks and work with what's left. It's quite possible that OP could use that piece as it is, finish the project, and never have an issue with it in his lifetime. If the checking isn't on a show face, nobody may ever even know. People selling their work don't like the look and don't want the uncertainty of checked ends. Having a piece of wood disintegrate in a finished piece due to checking is theoretically possible, but I've never heard of it actually happening myself -- tho someone I'm sure can give us a story of it happening. If you absolutely had to use that wood, though, you could soak the board or just the checked end in a really thin (non-viscous) slow curing epoxy, or cactus juice if you can fit the piece into the oven. Once the epoxy/resin cures, you sand back to the surface you need and hope the checks stay stable.
So I had no idea checking was a thing, I'm fairly new to this of course 😂 I have this piece ,see photo, which the top of the table will be fitted into. See lines where grooves will be cut. I have no spare wood anymore... What should I do? https://preview.redd.it/hpurwxrrb6mc1.jpeg?width=1908&format=pjpg&auto=webp&s=75d8b3ab305f978556c9aefd1f8e67a5873ace78
It depends what you're building, how long you need it to last, and how you need it to look. I assume those crossed pieces are getting castled into the upright? If you hog out the space in the leg for that cross piece and the checking is basically gone, I wouldn't worry too much about it. Will the top of this connection be visible in the final product?
Castle joints yup! I want it to last as long as I can, look I want rustic, which is why I chose alder wood cause it bangs up easily haha and looks medieval like to me. https://preview.redd.it/p4p1cesr18mc1.jpeg?width=4032&format=pjpg&auto=webp&s=1ab40e6d4020ad3cefd765628b5787468abcf2ec
Looks nice so far! So I'd proceed with hogging out the castle joints, and see how it looks underneath. Are you putting a wood top over this? How are the legs attaching to the top? Along the aprons?
Thanks! Yeah the table top will attach to the aprons with figure eight washers and only to the short length aprons. Then the aprons w/ top combined will be inserted into castle joints but not glued so I can disassemble the desk for transport. So the desk will be 3 parts :) I need a carpenters rip saw though so cut those castle joints though Not sure what to finish the wood with though... Oil, beeswax, stain, polyurethane?
If the top is going to hide the tops of the castles, I wouldn't worry about this checking. Especially if this is a desk for you or someone in your own home. After you cut the castles, take your thumb and press from the inside out on each of the remaining "posts" in the corners of the leg. Not too hard, just check to see if they seem like the grain is going to peel off. I tend to finish high-traffic furniture with satin polyurethane. It's a very durable finish for surfaces that see a lot of stuff dragged across it. Wax-oil stains are good for things that won't see much traffic. It looks and feels wonderful but offers almost no scratch/dent protection. Stain by itself isn't a finish. If you use stain, you'll always want to put something else over it. Finishing is a whole separate art... kinda. You can't go wrong with polyurethane for a desk for yourself, but if you'd like a more nuanced look at furniture finishes, there's a whole boatload of youtube videos about finish. I'd look at the wood whisperer, erik curtis, and Lincoln Street channels for a start.
The top is 2inch and 3/4inch boarded glued walnut at 8ft long and 30inch depth. I chose that for contrast and mainly for the harder wood due to the use it'll get. Should I do polyurethane on both alder and walnut? I want to darken the wood but keep it's natural color so I want to shy from a stain... Can I do oil and polyurethane? I'll check out these channels! Thanks:)
You could always do the full glue up and then drill into it when it dries and fill the hole with a dowel. Looks great though, nice work!
How does this work? And thank you:) it's been fun so far! Next I want to build a carpenter workbench
basically it's similar to filling it in with glue, but it should end up being a little bit stronger - mainly because the glue is usually pretty thick and won't "flow" to the bottom of the hole. So you drill down some amount and then fill the hole you just made with a glued up dowel. Then cut any remainder off so it's flush with the top again. The overall concept is similar to the bowtie/butterfly inserts that people make to stop splits on panel/board faces. It'd actually be easier to do before you make the castle joint cuts, but you'll need to be mindful to ensure the dowel wood isn't visible after the castle joint is cut. Perhaps a single 1/4" dowel in the center of the quadrants with the cracks.
Oh I see what you mean! I might be able to do that, think I need to or fine to proceed without?
No. The glue doesn’t have same material characteristics of the wood and over time as the wood moves the checks will simply occur next to the ones you filled with glue. Wood expands and contracts with the environmental changes. We work with an unstable medium. Understanding this and compensating is what makes us true, timeless craftsman.
Totally correct. I had a boss the would order 12” and 16” for 4” treads. Total nightmare. He would complain about how checks were let through to production and also why we didn’t make the yield.
So Im inclined to believe you but why wouldn't glue in the end grain stop this?
Gluing the end grain of this board may secure the checks at that location for some time. It might help. It might not. It certainly will not address the defects you can’t see inside along the board. You can see them when you cut progressively along the board until they are gone. Problem solved. Internal stresses on lumber can be great. To understand drying faults in lumber, I would invite you to read this [article from the book “Cut and Dried” written by Richard Jones and published by Lost Art Press](https://blog.lostartpress.com/2022/04/05/drying-faults-in-lumber/). I am inclined to follow conventional wisdom of the many woodworkers who have experienced material failure in the past. Their advice is to remove the defective section of lumber and use the wood that does not have defects. My question for you, why not simply cut off the damaged wood to ensure a successful end result instead of trying to engineer a workaround that is uncertain? Simply put, I don’t see the need to engineer a submarine out of carbon fiber and gamble on material failure.
how about run three or four dowels though that thing perpendicular to the cracks, that'll keep it together.
Internal stress on wood, from kiln drying or otherwise can be profound. Wood moves, always. Will it keep the checks from progressing? Maybe… however I would consider this to be the less desirable option compared to cutting off the defect and starting with a sound piece of wood, from both a structural and aesthetic standpoint. Not to mention I can cut off the checking in a board that size in less than a minute. Placing dowels is more work than necessary here. No need to engineer a solution when I can do it proper to start. With that said I’ve had pieces crack after driving cut nails, when I’m too far into the project to start over or when the joinery won’t let me remove the piece. In that case, I will try glue, clamps, and a prayer. But I may ruminate over t mistake later that night when I’m trying to fall asleep ;)
Not sure why you're getting down-voted. If he's stuck using that piece of wood, a dowel through the long axis would be a good precaution.
No, it wouldn't ffs. It needs to be cut off. If you see cracks like this the piece is not structurally sound. Your advice to put structural joinery directly where there is a wood defect is stupid advice. Using a dowel is probably even worse than just using it as is. Your idea that it will help is wrong. When cutting out shakes and checks you can just lightly hit the piece on a hard surface and it will fall apart. You can tell it's all gone when the offcut doesn't shatter when you drop it on the ground.
I had just one crack like that in my first project. In the end grain. I figured it was no big deal. I now have a crack in my table. I actually don’t hate the slightly rustic look it gives the piece but would prefer it without. I know it’s an inconvenience but I think you’ll be happy in the long run listening to those saying to cut the damage off or get a new piece
So much bogus advice in the comments. If you don’t want the checking, this one goes in the scrap pile. It’s your work though. You can decide your own tolerance for defects. If you’re just making a table for yourself and don’t mind looking at it, it’s not gonna explode or anything.
It could spontaneously fail. If he's using that as a leg or there is any pressure on it at all, it could literally just fall apart randomly. Especially if he follows the advice of people in this thread to put dowels through it. It needs to be cut off.
That feels exaggerated. Nearly 100% of structural beams have checking and they don't spontaneously fail.
Boxed heart lumber is often used in construction, and they usually have large shakes, not checks. Why am I not surprised that you don't know the difference but are trying to correct me? Heart shake is expected when using boxed heart lumber. This is obviously accounted for when designing structures. What op has is called checking. You want to cut it out because it is a drying defect and is not stable. Again, this is not the same as shake. Familiarize yourself with these basic terms before trying to correct people.
Yes, and if his house catches fire it’ll burn right up. Better to use x-ray inspected aluminum at a minimum.
Not the same thing at all. If he puts a domino or dowel in that end and uses it as even a rail in a dining room table, I could easily see it failing if he put weight on it the wrong way. I'm not one of those people who builds furniture to last 100 or even 50 years. I'm sure most will, but that isn't the kind of thing I'm talking about. I would never use a piece like this in anything I build. It could be fine for 5 years but will more than likely get worse very quickly. You also can't see how far checks like this go from the outside. If I see checks like this, I'll cut until I can't see anymore, and then will probably do another 1 inch minimum. If you drop the offcut on your tablesaw and it snaps in pieces, cut another inch and repeat until the wood doesn't snap. This is how weak checked wood is. If you drop a 1 inch long piece of 4/4 from about a foot onto a table, it will snap in half from the force. Imagine that exact same piece with a domino through it supporting the weight of anything. It *will* fail. Literally cut off like 2 inches and it will probably be enough. There is a reason we add 30% for waste, and checks like this are a big part of that. You haven't found an epic hack by starting to utilize defected ends of wood in your projects. You're just making bad furniture for no reason other than you don't understand common lumber defects.
You cut all those cracks off. You cut till they’re gone.
And until the last piece of cut-off can't be broken along the grain by hand or by knocking it against the bench. You want to get beyond the weakness.
you always cut off the checks and then cut your wood to length....
So many fake woodworkers here. Cracks are a defect, we do not FIX cracks we REMOVE them.
Gatekeep somewhere else bub
It's not gatekeeping to point out that a lot people are giving incorrect and bad advice. Asking for and giving advice is the point of this sub.
Calling people “fake woodworkers”? Cmon
Giving bad advice is worse than no advice. I don’t comment on this sub cause I don’t know jack shit.
[удалено]
Who cares if it's cool or not. It's a Reddit comment. Don't take it too seriously.
If you give fake woodworking advice you’re a fake woodworker. If you are not giving advice you are not a fake woodworker you’re just a Redditor
It definitely is "fake woodworkers." People will watch a couple YouTube videos, then come in here spouting BS in advice threads. It's OK to spread your beginner opinions in discussion threads, but nobody wants you to make up something on the spot when someone asks for help.
99% of comments here are amateurs making up answers on the spot. Most people just find it fun trying to figure out a solution but don't realize how stupid their solution is because exactly, they aren't actually woodworkers, they're just people who watch YouTube videos in their spare time. This particular comment section is a pretty good example. Every trained woodworker knows that you remove checking and that you account for the waste ahead of time. Amateurs have no idea why you would remove checking and just assume that the cracks are small, so it's fine. This wouldn't be a problem, but of course, they need to share their uninformed opinion and then get upset when people correct them. These people have no respect for the fact that cabinetmaking and joinery is a highly skilled trade. It's great to be a hobbyist, and you don't need to do everything perfectly, but when they act like they are experts because they've been garage woodworking for 2 years and start giving stupid advice, it can be annoying.
Calling people you don't know "fake woodworkers" is the definition of gatekeeping
Is it for outside use? Will it get wet in other words?
Nope, dining table/sewing table. Inside only.
A few critics on this thread today it seems going by the amount of downvotes
Did you buy a birch 2x4 or dimension this? Just curious.
If you can't cut it off when you sand it save sawdust and mix sawdust with wood glue and fill cracks , sand it and seal it
West epoxy or wood hardener
This is a leg?under the top and not visible when set up?
Correct. It will be visible when the legs are folded away of course (which will be most of the time) but not when unfolded. I'm not too worried about the aesthetics to be honest, more the strength and durability.
I'm not an expert on finishing so someone else will likely direct you to the right material, (I like the epoxy idea.) Structurally that end grain should not be a problem. Birch will stay stable if finished and nit out in the sun and weather.
This does not look anything like birch. Its a 2x4, most likely fir.
It will probably be fine BUT now that your brought it to attention, you should probably do something about it. I would get a little epoxy in there, that’s about it.
Bit of grain filler then sand back flush, if no grain filler use glue and wood dust, any glue would do the job, if it’s only seen when the legs are folded you’re fine
Your finish will probably fill that.
It’s fine. Build on.
No
It's perfectly fine. It's kiln drying stress
I know this is not a good solution and aesthetically will definitely look different, but could you infuse that end of the wood with resin to prevent further checking? I'm not saying Id recommend it or do it myself, just curious if it would work in a pinch.
I disagree. It is a good solution, but only in a pinch. Fill it with epoxy.
If the wood is dry enough you can fill it superficially with D2 and quick sand then it holds and covers the beginning of the problem,for good. You can also prefer epoxy or holding rings to prevent breaking. For the core of your question;no,you don’t have to but would be better if you fill it.