I had a friend looking for the above nut. I told him to try McMaster Carr. He stopped by yesterday and gave me two 1 1/4-7 nuts that thread just fine on my lathe. How can this be? There is no play in it and it threads on all the way to the plastic washer. Any thoughts on if this could damage the threads or?
-
December 2025 Turning Challenge: Single Tree! (click here for details) -
Congratulations to Bob Henrickson, People's Choice in the November 2025 Turning Challenge (click here for details) -
Congratulations to Guillaume Fontaine for "Old Tea Pot" being selected as Turning of the Week for December 15, 2025 (click here for details) -
Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.
1 1/4-8 nut
- Thread starter Sam Force
- Start date
john lucas
AAW Forum Expert
If you don't have to force it you should be ok. Are you sure the nuts are 7 tpi. That is a standard size. 1 1/4x 8 nuts are for special applications and not common. Of course for whatever reason lathes picked 1" 8 abd 1 1/4 x8 as a standard.
It came from a local bolt supplier and was IDed as 1 1/4-7
This brings up the question of "if 1 1/4 by 7 tpi is industry standard, why are lathes 1 1/4 by 8 tpi?
robo hippy
robo hippy
7 tpi thread is a no go.
FWIW, I ran into the other side of this supply problem – looking for 1-1/4x8tpi rod for a storage solution. It's super hard to come by... until I had the "oh I have a 3D printer now" facepalm moment and had a threaded flange printing up not long after. (This was for wall storage of a sanding disc, fwiw.) My first guess at a "nut" with true threading for this size, depending on the precise need, would be to buy an inexpensive small faceplate.
As to why the 1-1/4x7 nut seems to fit... close threadings have an annoying tendency to almost fit, if not too many turns are required. I have to suspect that's what's going on here?
related to close threadings, imagine my vague cursing in the shop from a few weeks back on a project that had both 10-24 x 2-1/2" bolts AND (the extra cursed size) 12-24 x 2-1/2" bolts. close enough that threading the #10 into the #12 by hand for a test fit feels right, but under load just slips out like the threads have been stripped. but then the threads are fine on inspection. ? ?? ?!??? both with the same head style, despite completely different vendors, in very similar clear bags upside down on the bench. I'm still slightly miffed at the nameless engineer who spec'ed a hole size intended to be tapped at 12-24.
McMaster Carr does in fact have 1 1/4 x 8 nuts. If yours fit, they fit, but I suspect they were mislabeled at the local supplier. Easy enough to count the tpi yourself or use a thread gauge. Very hard to believe a 7 tpi nut would thread all the way onto an 8 tpi spindle unless it was a super sloppy fit.
My son-in-law has (or had?) an old lathe with the 1-1/4 7tpi spindle. A few factory face plates with that thread also came with the lathe. And, yes, I did verify it is actually 1-1/4 7.
To further confuse the issue a M33-3.5 nut might be a close fit on a 1-1/4 8 spindle. M33 is a somewhat common wood lathe spindle size.
To further confuse the issue a M33-3.5 nut might be a close fit on a 1-1/4 8 spindle. M33 is a somewhat common wood lathe spindle size.
Last edited:
The nut in question fits tight on my 3520 so not sure where the issue is but it seems to be a good, tight fit. Will have to get it set into a face place to see how it holds up during use
- Joined
- Feb 6, 2010
- Messages
- 3,457
- Likes
- 2,525
- Location
- Brandon, MS
- Website
- threeringswoodshop.square.site
Been a few years but I got a 1 1/4 8 bolt and nut at Ace Hardware
I would not use it on my lathe without determining that the actual pitch was correct. A thread gauge makes it simple to check, but it's easy to count and measure between some thread crests.
In addition to sets of thread gauges, for common sizes of smaller bolts and nuts I keep one of these hanging in my shop, both SAE and metric. I saw one at my favorite auto parts store and although they didn't carry them, they were glad to order one. I see them for sale on Amazon - can search for thread size checker.
JKJ
In addition to sets of thread gauges, for common sizes of smaller bolts and nuts I keep one of these hanging in my shop, both SAE and metric. I saw one at my favorite auto parts store and although they didn't carry them, they were glad to order one. I see them for sale on Amazon - can search for thread size checker.
JKJ
It is obviously mislabeled as shown above a 1 1/4 X 7 would not fit a 1 1/4 8 thread.
I had looked at ordering them, but was pleasantly surprised that Fastenal happened to have them in stock, at a better price, right here in our small up-north town.
That's right^^^...one or the other is being confused.
Both pitches are common and "standard"...7 tpi is the UNC standard, and 8 tpi in a UN standard that is often found in stud-and-nut combinations.
Coarser threads are often preferred on spindles as they are easier to remove since their helix angle is greater; they are less likley to lock as much.
Tim
Another vote for mislabeled.
Sometimes there is a code on a nut or bolt that can be looked up on line.
Sometimes there is a code on a nut or bolt that can be looked up on line.
I couldn't figure out why you wanted a nut, but
I suggest you consider an alternative solution Threaded Wood Faceplates. You buy or borrow a tap and then drill and tap the wood and you're off to the races. The are numerous documents and videos on the process. This is a link to a video from Mike Peace on this. If you only want one threaded work holding device (faceplate) then the nut path is cheaper. You will obviously perform your own cost benefit analysis. Good luck and safe turning.
I bought one of those 1-1/4"x8 taps for wood and it works well.
Beall has them, but I see they're out of stock at the moment.
woodturnerscatalog.com
But it looks like they're available at Lee Valley and Prime Tools
Note that if you have an 1.25x8 steel bolt you can make a tap for wood with some grinding tools. I've done that many times with smaller bolts, usually with just a file.
JKJ
Beall has them, but I see they're out of stock at the moment.
Beall Spindle Tap
Making custom wooden jigs and fixtures that thread directly onto your lathe spindle is easy and inexpensive with a Beall® Spindle Tap. Just drill a pilot hole in the wood, thread the tap into the blank, and turn yourself a jamb chuck, jig or whatever you need in only minutes. Being made of wood...
woodturnerscatalog.com
But it looks like they're available at Lee Valley and Prime Tools
Note that if you have an 1.25x8 steel bolt you can make a tap for wood with some grinding tools. I've done that many times with smaller bolts, usually with just a file.
JKJ
I use a nut to make a 20 inch disc sander, 2 for making cupped blocks for holding spheres to turn off the nubs.
They are very close in size, but they will only go on one or two threads before jamming in my experience.