Chair leg caster repair

[Brian Runau]

I bought four of these nice oak chairs to go with a little eat in kitchen table I built. Made the mistake of using a 3/8" caster post with a T-nut with the sharp nail in flanges. Casters have fallen out multiple times. I used epoxy to reinstall them. This morning one of these came out and damaged the side of the leg. Blew out the wood. Insert expletive of your choice here.

I can clean them up, glue the blow out back on and even insert a dowel and glue it in and shave it level with the bottom. Buy 1/4" post casters or remove the casters all together and shorten the legs on the table. Chairs are heavy and casters are nice, but have proven to be a pain due to installation errors. I could even switch to screw on t-nuts, but not sure they would work based on the previous t-nut install damage from the sharp points on the bottom of the leg.

I have stain to match, but the thought of trying to cut off the bottom portion of the leg and putting on short pieces and starting over feels a little daunting.

Welcome any suggestions on best fix to salvage the chairs.

Thanks. Brian

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[Doug Garson]

I wouldn't use casters, use nylon chair guides like these:


https://www.amazon.ca/dp/B08JH52J92/ref=sspa_dk_detail_4?psc=1&pd_rd_i=B08JH52J92&pd_rd_w=1ro5v&content-id=amzn1.sym.d8c43617-c625-45bd-a63f-ad8715c2c055&pf_rd_p=d8c43617-c625-45bd-a63f-ad8715c2c055&pf_rd_r=424MY137Q2Q92N1Q4DCW&pd_rd_wg=jPle4&pd_rd_r=9c3d30c3-417b-4fb7-a613-4c116e3b68d9&s=kitchen&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw

We have these, or similar ones on chairs and other furniture on both hardwood floors and carpets and they work well on both.

[Richard Coers]

I wouldn't use casters, use nylon chair guides like these:
We have these, or similar ones on chairs and other furniture on both hardwood floors and carpets and they work well on both.

Casters are fine for us more elderly folks, but choosing the proper size is critical. I suggest you epoxy in a dowel and fill the holes. Then buy a 1/4" stem caster with an insert that has a round flange insert with lots of little teeth.

[stephen thomas]

I repair stuff like that; and have also added urethane or rubber casters to a lot of furniture in the house - it is easier on the floors - as well as old backs and such.

I always drill the wooden leg undersize and tap it. Sometimes at that point i saturate with epoxy, and screw the caster in.

When it matters to me, or for repairs, i first make a phenolic tube insert, and glue that in with epoxy.
In order to re-inforce the existing leg, the insert should not be too short.
A dowel won't help you, it is all short cross grain like the leg that failed.

If you try my method, rough up the OD of the tube, and nick a positive groove in it with a handsaw to allow pressure release from the glue.
If i am making this for someone else or the legs have to be adjustable, i screw a sacrificial well waxed bolt in the whole way (but not beyond), to keep the glue out & dab a little wax in the glue end.

Do not use un-specified "round" phenolic rod - it is cut from sheets (like a wood dowel) and ground round in a centerless grinder. Yes, it is a lot cheaper than woven & rolled tube, but it is about as effective as installing a wooden dowel, It might even split easier. You want woven and rolled linen phenolic rod or tube, either L (linen) or C (canvas). If you have a wood lathe with a tailstock drill chuck, the inserts can be drilled and tapped that way. Maybe hand turn while tapping unless you also have a releasing tap head. If you have a metal lathe, you probably don't need my advice. :)

The phenolic will expand and the tapped hole can be undersized. Plan on re-tapping after it is glued into the chair leg.

Also don't use short setting epoxy, especially not 5 minute epoxy - it has no strength long term. Use a real epoxy that maybe has some filler, and takes at least a couple hours to set.

Leg shown do not have casters, but will get adjustable feet.

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520595

[Doug Garson]

Casters are fine for us more elderly folks, but choosing the proper size is critical. I suggest you epoxy in a dowel and fill the holes. Then buy a 1/4" stem caster with an insert that has a round flange insert with lots of little teeth.
The danger with casters, especially on hardwood or tile floors is the chair can move too easily when getting in or out of the chair and cause a fall. The nylon guides provide enough resistance to avoid this but are still easy to move for us seniors. I can push our dining chairs on a hardwood floor with one finger but it stops moving when I stop pushing while a chair on a caster could roll even after I stop pushing.

[Richard Coers]

The danger with casters, especially on hardwood or tile floors is the chair can move too easily when getting in or out of the chair and cause a fall. The nylon guides provide enough resistance to avoid this but are still easy to move for us seniors. I can push our dining chairs on a hardwood floor with one finger but it stops moving when I stop pushing while a chair on a caster could roll even after I stop pushing.
That's fine for you, but they don't work here. My wife's leg joints are troublesome, even the replacements. She can take no weight with her legs for moving. She has to have wheels or she doesn't move. She does rotate the chair so it's not far from the wall when she gets up or sits down. No solution is a universal fix for everyone.

[Brian Runau]

[QUOTE=stephen thomas;3318366]I repair stuff like that; and have also added urethane or rubber casters to a lot of furniture in the house - it is easier on the floors - as well as old backs and such.

I always drill the wooden leg undersize and tap it. Sometimes at that point i saturate with epoxy, and screw the caster in.

When it matters to me, or for repairs, i first make a phenolic tube insert, and glue that in with epoxy.
In order to re-inforce the existing leg, the insert should not be too short.
A dowel won't help you, it is all short cross grain like the leg that failed.

If you try my method, rough up the OD of the tube, and nick a positive groove in it with a handsaw to allow pressure release from the glue.
If i am making this for someone else or the legs have to be adjustable, i screw a sacrificial well waxed bolt in the whole way (but not beyond), to keep the glue out & dab a little wax in the glue end.


Stephen, I am having trouble following what you are suggesting for a repair. Glue in a phenolic tube(hollow tube or solid rod? to reinforce the drilled hole? Thanks Brian

[Jimmy Harris]

I like casters on carpet, but on hard floors, they're just too dangerous, as they can slip out from under you when you try to sit down. And I'm not even old. So I do prefer the nylon glides on hard floors. However, the nylon glides won't allow you to stay seated and roll around. Pros and cons either way. And that's your decision to make.

But, if you do stick with the casters, get the ones with the longer stems. I'd go with a minimum of 1.5" stems. The longer, the better. Get the kind that friction lock into a metal insert that's just hammered in place so the weight of the chair is what primarily keeps them in place. They won't fall out unless you pull them out. And since the caster insert doesn't have screws, it's less likely to split the thin wood on the sides. Refill the current holes with hardwood dowels and redrill if need be.

In all honesty, you probably made the leg too thin to properly support casters that would be subjected to such forces. Not much you can do about it now. Your best bet at this point is to spread the horizontal load across as large an area as you can to prevent further damage.

[stephen thomas]

Stephen, I am having trouble following what you are suggesting for a repair. Glue in a phenolic tube(hollow tube or solid rod? to reinforce the drilled hole? Thanks Brian

Yes, a woven rolled phenolic tube adds a lot of crush resistance to the stem area.
Given a wallered out hole, drilling it and gluing in a suitable length tube adds strength.
Especially if the tube is epoxied in with good epoxy, with suitable filler if indicated; such as WEST with cotton flocking added..

It just makes the whole joint area a lot stronger.
Basically stuff like that starts to fail when the (soft wood) substrate gets compressed. The the stem works back and forth and all around until it has enough leverage to blow out a side.
A reasonable wall thickness woven rolled phenolic tube is much more resitant than wood. The fact that it is installed deeper, and has a larger od surface area increases mechanical advantage in your favor.

One think that may have been confusing : I always use threaded stems, not smooth. For one thing, they trend longer so are less likely to waller.
No T-nuts. If you plan to re-use the existing, they might not be long enough for my method to gain you much. But having a longer, say 1/4" wall tube would be better than trying to make the T-nut work again. It won't.

If it is good solid hardwood, i will cut the legs to accommodate the increased height of casters, and drill and tap it for threaded stems. Then i saturate it with epoxy and carefully, slowly screw the stems down until the collar butts. This is easier than installing phenolic tubes/dowels, and if things work out, there will be no need to. The fall back position is phenolic tubes when it is a repair to a wallered out situation, like my wife's old oak Gunlocke office chair repair.
The system is same as shown in the photos in my original post this subject.

[stephen thomas]

Maybe this will help-
The legs in this chair were totally wallered out, the last persons' attempt to fix it was something like what you used.
I (carefully) drilled the holes for 7/8" diameter x 1-3/4" long (or maybe 2") phenolic rolled canvas dowels & epoxied them in with WEST/cotton flocking mix.
You can see the saw cut for the glue relief slot on lower edge of the close up photo. This also provides a strong key to help resist breaking the bond when you screw the new caster stems in hard.

I cranked the bushings out on a turret lathe, and have (sometimes freehand) ground the tap necks undersize so the threads can go deeper than factory allowance with an un-reduced shank.

However, as mentioned, this can be done on a wood lathe almost as easily. If you have to tap for a long stem, (which makes the chair leg stronger) it might be necessary to reduce the shank on a tap to allow the depth by careful free-hand grinding it. Grind off the top-most /imperfect thread on the tap while reducing the shank.

I truly cannot recall how i cleanly drilled out the old wallered holes and controlled for depth.
Might have been a quick wooden clamp-on fixture. More likely i probably took the base to a drill press and clamped it with the table swiveled sideways, or in a quick wooden fixture.
Whatever it took to fixture each wing solidly with no chance of kicking out or having the bit deflect and cause other mayhem.
The idea for repairs like this for me, is to not do it half way and end up just kicking the can down the road to do it all over again in a few years. (or next week)

If you do not want to use threaded stems, a simple close fitting bore could work if the straight stems are long enough. The fit needs to be snug to tight, though. This type wear is by constant miniscule motion and fretting, until parts can move far enough that the leverage of the displaced stem breaks pieces in small chunks and then blows a side out.

520607520608520609\

If you click twice on the last/close-up photo to blow it up further, the saw-kerf glue slot can be seen, as well as vestiges of the crimps in the wood, from the last person's drive-in hardware.

Good luck, whatever method you choose!
smt

[Brian Runau]

Maybe this will help-
The legs in this chair were totally wallered out, the last persons' attempt to fix it was something like what you used.
I (carefully) drilled the holes for 7/8" diameter x 1-3/4" long (or maybe 2") phenolic rolled canvas dowels & epoxied them in with WEST/cotton flocking mix.
You can see the saw cut for the glue relief slot on lower edge of the close up photo. This also provides a strong key to help resist breaking the bond when you screw the new caster stems in hard.

I cranked the bushings out on a turret lathe, and have (sometimes freehand) ground the tap necks undersize so the threads can go deeper than factory allowance with an un-reduced shank.

Stephen: Think I get it now. Ingenious solution. I don't have the tools to do what you did, nor I suspect the tools. Thanks for taking time to explain. I think it gave me an idea though. What if I use your phenolic insert to plug the hole and then used a brass threaded insert and changed the caster post size? These are for soft woods. Thanks Brian

https://www.ezlok.com/for-wood/for-soft-wood/ezhex-threaded-inserts-for-soft-wood?page=2

[stephen thomas]

Brian -
Yeah, essentially all my other verbosity boils down to: "Stick a [rolled linen or canvas phenolic] dowel in it, and epoxy well. Don't forget to use a glue-relief slot to avoid hydraulic build up that can split the leg it is going into."

I do not know if the thread serts you show will easily go into phenolic, nor if they will stay there under the stress of the chair loads once installed. I make and use proprietary thread serts here, have used the commercial products, but am not impressed and would not use for casters. The length of them is too short for the app. Thread serts tend to work well in plywood, and across the grain in solid wood. Less well in end grain. Something i have done in the past when my concern is leveling, or that it might be necessary to replace casters at a later date, is make "very long" threadserts here in the shop, tap the wood for them, and glue them in with epoxy. But i thing that generally rolled linen phenolic is better for matching the wood characteristics, and "probably" stays glued (epoxied) better than metal in wood. If you are even thinking about it, i once tried super glue and it was a failure. (the bond failed quickly) Then again, you might have better luck.

You should experiment with whatever size hole you drill in the phenolic, glue some in sample boards, and see how the thread-serts work in phenolic. Phenolic drills and taps "easily" but the whole point is that it is tougher than wood, so self-tapping inserts might or might not work, and might or might not require a different diameter hole than spec'd for wood.

The 25mm length might possibly be ok, if the phenolic tube is longer up into the leg to reinforce it. 13mm=1/2" is way to short for the loads. If you just stick a 10mm dia thread x 25mm long thread sert into a (minimum) 7/8" diameter phenolic dowel, the dowel will be short and the wood will fail from the leverage. If, instead, you use a 3/4" or 7/8" dia phenolic dowel, insert it 2" up the leg, and then directly drill and tap for the stem of the caster in the center of it, the geometry of the mating parts gets better.

I merely suggest doing the drilling and tapping before inserting, because doing so on a (wood) lathe makes it easier.
It can be done after epoxying solid rolled fabric phenolic dowels in place if preferred.

The larger the diameter of the phenolic, the better, to resist crushing from the caster stem. However, at some point, the larger phenolic dowel will result in too little wood being left in the chair leg. So you have to figure that yourself, but it is why i suggest a minimun 3/4" diameter phenolic dowel if it is drilled and tapped on center directly, for a 3/8" threaded stem. Or 7/8" minimum if there is also a thread sert added to the mix. If you use the thread sert in a pre-drilled tube, i would epoxy it in. Again, "real" epoxy, not the 1/2 hr or 5 minute or other short setting stuff that has no long term durability.

I'm obsessive because i see lots of failure in lots of systems and end up repairing them. I really hate having to re-repair my own work. The pieces shown so far are only 2 of "more than a few" rolling wooden platforms with casters that i have built, some in commercial use. The details make the system. Some people do get away with less obsessive approaches than i tend to take, though.

Good luck!

[Brian Runau]

Brian -
Yeah, essentially all my other verbosity boils down to: "Stick a [rolled linen or canvas phenolic] dowel in it, and epoxy well. Don't forget to use a glue-relief slot to avoid hydraulic build up that can split the leg it is going into."

I do not know if the thread serts you show will easily go into phenolic, nor if they will stay there under the stress of the chair loads once installed. I make and use proprietary thread serts here, have used the commercial products, but am not impressed and would not use for casters. The length of them is too short for the app. Thread serts tend to work well in plywood, and across the grain in solid wood. Less well in end grain. Something i have done in the past when my concern is leveling, or that it might be necessary to replace casters at a later date, is make "very long" threadserts here in the shop, tap the wood for them, and glue them in with epoxy. But i thing that generally rolled linen phenolic is better for matching the wood characteristics, and "probably" stays glued (epoxied) better than metal in wood. If you are even thinking about it, i once tried super glue and it was a failure. (the bond failed quickly) Then again, you might have better luck.

You should experiment with whatever size hole you drill in the phenolic, glue some in sample boards, and see how the thread-serts work in phenolic. Phenolic drills and taps "easily" but the whole point is that it is tougher than wood, so self-tapping inserts might or might not work, and might or might not require a different diameter hole than spec'd for wood.

The 25mm length might possibly be ok, if the phenolic tube is longer up into the leg to reinforce it. 13mm=1/2" is way to short for the loads. If you just stick a 10mm dia thread x 25mm long thread sert into a (minimum) 7/8" diameter phenolic dowel, the dowel will be short and the wood will fail from the leverage. If, instead, you use a 3/4" or 7/8" dia phenolic dowel, insert it 2" up the leg, and then directly drill and tap for the stem of the caster in the center of it, the geometry of the mating parts gets better.

I merely suggest doing the drilling and tapping before inserting, because doing so on a (wood) lathe makes it easier.
It can be done after epoxying solid rolled fabric phenolic dowels in place if preferred.

The larger the diameter of the phenolic, the better, to resist crushing from the caster stem. However, at some point, the larger phenolic dowel will result in too little wood being left in the chair leg. So you have to figure that yourself, but it is why i suggest a minimun 3/4" diameter phenolic dowel if it is drilled and tapped on center directly, for a 3/8" threaded stem. Or 7/8" minimum if there is also a thread sert added to the mix. If you use the thread sert in a pre-drilled tube, i would epoxy it in. Again, "real" epoxy, not the 1/2 hr or 5 minute or other short setting stuff that has no long term durability.

I'm obsessive because i see lots of failure in lots of systems and end up repairing them. I really hate having to re-repair my own work. The pieces shown so far are only 2 of "more than a few" rolling wooden platforms with casters that i have built, some in commercial use. The details make the system. Some people do get away with less obsessive approaches than i tend to take, though.

Good luck!

Appreciate your thoughts. My problem is I don't have any way to do it the way you are doing it. Thanks. Brian

[Brian Runau]

OK, so I decided I could only go with no casters, shame, but oh well. First chair drilled and 1/2" dowel installed in the hole of each leg. Now which guide to use. We have a sheet good vinyl floor, goes great with our Mission style design home. Quarter sawn oak cabinets(bragging), oil rubbed bronze, etc...

Concerned nylon glides might indent the vinyl? I run @ 235#'s. Go with felt even though they might not slide as well and or need to be replaced sooner?

Thanks. Brian

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[Jerry Bruette]

We also have wooden chairs but we have LVT and not sheet vinyl. We use the felt glides provided to us by the retailer we bought the chairs from. Our biggest concern was how well the glides would sick to the legs. In well over a year of use we've had no problems.

I wish I had a brand name of the glides that I could give you. They're not like the hard felt glides, but have a knap similar to carpet.

[Brian Runau]

We also have wooden chairs but we have LVT and not sheet vinyl. We use the felt glides provided to us by the retailer we bought the chairs from. Our biggest concern was how well the glides would sick to the legs. In well over a year of use we've had no problems.

I wish I had a brand name of the glides that I could give you. They're not like the hard felt glides, but have a knap similar to carpet.

Jerry, yours are adhesive, I've seen rectangular ones with rubber housing that are nail on, but nervous about nailing anything on. Thanks Brian

[Jerry Bruette]

Jerry, yours are adhesive, I've seen rectangular ones with rubber housing that are nail on, but nervous about nailing anything on. Thanks Brian
Yes ours are adhesive. I don't think I'd have anything that would nail on from the bottom up, maybe from the side.

[Doug Garson]

Since you have glued in a dowel it would be easy to drill a pilot hole and use a pad with a nail like the ones I linked to.