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I can't figure out what size this screw is, and I don't want to have to go to the store to find out.
I think it's metric, because it says 10.9 on the top, and because the socket part of the head takes a 5mm allen wrench. I think it's an M6 because the diameter of the shaft is about 6mm. I'd have said 7mm at first, but apparently M7 doesn't exist. It's certainly not M8, so it must be M6.
It's got 27 threads over a space of about 38mm, which comes out to 1.4mm per thread.
Per the table on this page, apparently M6 bolts don't come in anything over 1mm per thread.
It doesn't seem to match any SAE bolt sizes either.
I can't figure out where I'm going wrong. It's a bolt from a new office chair. There's no reason for it to be non-standard. And it looks totally normal.
I want to get a longer bolt of the same size, so I can slide in a piece of wood to make the back part of the seat raise up higher.
I already went through this rigamarole for my yoga chair, to make it higher. Those screws made sense when I measured them. That chair still needs a new cushion. And preferably new fabric. I just can't right now. And it would probably still be too low for this desk.
I've got so many different chairs in this room right now, and none of them are quite right for how I want to sit. It's ridiculous.
They don't really sell office chairs that are designed for sitting cross-legged.
At work, this year I finally removed the arms from my chair so that they wouldn't keep getting in the way when I sit with one leg crossed over. But the seat isn't big enough for sitting with both legs crossed.
At home, I have an old office chair which was already missing the arms and back due to an unfortunate incident several years ago, when both Qiao and I were sitting in it at the same time. We didn't end up with damage, but the chair did. It's not bad for sitting cross legged, but it's not high enough for my current desk. The seat cushion isn't flat either - it's raised on the left and right sides. That pushes my feet upwards when I sit cross-legged; I think a flat or downward sloping sides would be better.
So I searched for and finally bought a new chair with a wide, flat, well-cushioned seat. That is, in the store it felt completely flat. After assembling the one I bought, minus the arms and back, I noticed that its seat isn't really flat either. It has a slight depression in the center, especially towards the back. And the back is lower than the front.
When searching for a suitable chair, I also checked that it wouldn't have any hardware sticking out from underneath, if I left the arms and back off.
Both when sitting cross-legged and when not, it's easier to sit up straight when the back of the seat cushion is higher than the front. So I've been sitting on the chair "backwards". But in terms of the cushion not being completely flat, I think the cushion itself would feel more comfortable the other way around. Ergo messing around with screws and pieces of wood today.
..
Hah. I was able to get the chair slanted the way I want without needing new screws. After cutting back some fabric from the bottom of the seat to see what was underneath, I saw there were plastic spacers between the seat bottom and the part it connects to. I removed the spacers from one side, which has the same effect as adding the wood pieces on the other side would have had. Except that now, the chair is slightly shorter at its highest height. But I think this will do.
I think it's metric, because it says 10.9 on the top, and because the socket part of the head takes a 5mm allen wrench. I think it's an M6 because the diameter of the shaft is about 6mm. I'd have said 7mm at first, but apparently M7 doesn't exist. It's certainly not M8, so it must be M6.
It's got 27 threads over a space of about 38mm, which comes out to 1.4mm per thread.
Per the table on this page, apparently M6 bolts don't come in anything over 1mm per thread.
It doesn't seem to match any SAE bolt sizes either.
I can't figure out where I'm going wrong. It's a bolt from a new office chair. There's no reason for it to be non-standard. And it looks totally normal.
I want to get a longer bolt of the same size, so I can slide in a piece of wood to make the back part of the seat raise up higher.
I already went through this rigamarole for my yoga chair, to make it higher. Those screws made sense when I measured them. That chair still needs a new cushion. And preferably new fabric. I just can't right now. And it would probably still be too low for this desk.
I've got so many different chairs in this room right now, and none of them are quite right for how I want to sit. It's ridiculous.
They don't really sell office chairs that are designed for sitting cross-legged.
At work, this year I finally removed the arms from my chair so that they wouldn't keep getting in the way when I sit with one leg crossed over. But the seat isn't big enough for sitting with both legs crossed.
At home, I have an old office chair which was already missing the arms and back due to an unfortunate incident several years ago, when both Qiao and I were sitting in it at the same time. We didn't end up with damage, but the chair did. It's not bad for sitting cross legged, but it's not high enough for my current desk. The seat cushion isn't flat either - it's raised on the left and right sides. That pushes my feet upwards when I sit cross-legged; I think a flat or downward sloping sides would be better.
So I searched for and finally bought a new chair with a wide, flat, well-cushioned seat. That is, in the store it felt completely flat. After assembling the one I bought, minus the arms and back, I noticed that its seat isn't really flat either. It has a slight depression in the center, especially towards the back. And the back is lower than the front.
When searching for a suitable chair, I also checked that it wouldn't have any hardware sticking out from underneath, if I left the arms and back off.
Both when sitting cross-legged and when not, it's easier to sit up straight when the back of the seat cushion is higher than the front. So I've been sitting on the chair "backwards". But in terms of the cushion not being completely flat, I think the cushion itself would feel more comfortable the other way around. Ergo messing around with screws and pieces of wood today.
..
Hah. I was able to get the chair slanted the way I want without needing new screws. After cutting back some fabric from the bottom of the seat to see what was underneath, I saw there were plastic spacers between the seat bottom and the part it connects to. I removed the spacers from one side, which has the same effect as adding the wood pieces on the other side would have had. Except that now, the chair is slightly shorter at its highest height. But I think this will do.
no subject
Date: 2019-04-08 04:39 am (UTC)From:Counting thread pitch is really difficult to do accurately even with a micrometer. A thread pitch gauge and a microscope is usually enough. I still have some stuff I have never managed to find the thread pitch for, on the Spitfire. It isn't any standard metric or imperial thread.
no subject
Date: 2019-04-08 05:02 am (UTC)From:I guess you're right, the ones for this chair must be non-standard.