Left hand thread nut dilemma

[runswithsizzers]

New user; apologies if I am posting in the wrong forum.

I have a made-in-Taiwan drill press that needs a lefthand threaded nut to secure the pulleys on a tapered spindle.

As best as I can measure, the male spindle threads are EITHER: M22 x 1.5mm - or - 7/8" x 16 tpi. I believe my 16 tpi thread pitch gauge MAY be fitting a little better than my metric 1.5 gauge, but I am not certain.

I can find left hand M22 x 1.5 nuts at McMaster-Carr, but so far, I can't find any source for left hand nuts in 7/8" x 16 tpi.

McMaster-Carr offers the M22 nuts in thick or thin, and in steel (low and medium strength), stainless steel, or brass. If it turns out the actual thread size is 7/8" and not M22, is there any possibility a M22 nut might fit well enough to work?

If I get the thin brass nut, it might tolerate a misfit better than a thicker nut in hard steel, right? And brass would be less likely to damage the male threads on the spindle. On the other hand, the nut itself is more likely to strip, if thin and brass.

Any other options I have not thought of?
thank you

 

[Bill D]

Whitworth?

 

[runswithsizzers]

Whitworth?

Thanks for your reply. Are you asking if the threads on my drill press might be Whitworth? Or suggesting it may be possible to substitute a Whitworth nut for either 7/8" Imperial or 22mm metric threads?

I was in the bicycle business for 20 years, but except for a very few British bicycles, my experience with Whitworth is very limited.

Unfortunately, my ability to measure is limited to metric and Imperial screw pitch gauges and a 50 year pair of ELDI calipers that "might" be reliable to about 0.02mm and probably less.

 

[Illinoyance]

Find a friend who has a lathe and ask him to make a new nut for you. A gift of certain liquids might smooth the way.

 

[JohnEvans]

You said the secret work TAIWAN dollars to donuts Metric!

 

[CarlBoyd]

New user; apologies if I am posting in the wrong forum.

I have a made-in-Taiwan drill press that needs a lefthand threaded nut to secure the pulleys on a tapered spindle.

As best as I can measure, the male spindle threads are EITHER: M22 x 1.5mm - or - 7/8" x 16 tpi. I believe my 16 tpi thread pitch gauge MAY be fitting a little better than my metric 1.5 gauge, but I am not certain.

I can find left hand M22 x 1.5 nuts at McMaster-Carr, but so far, I can't find any source for left hand nuts in 7/8" x 16 tpi.

McMaster-Carr offers the M22 nuts in thick or thin, and in steel (low and medium strength), stainless steel, or brass. If it turns out the actual thread size is 7/8" and not M22, is there any possibility a M22 nut might fit well enough to work?

If I get the thin brass nut, it might tolerate a misfit better than a thicker nut in hard steel, right? And brass would be less likely to damage the male threads on the spindle. On the other hand, the nut itself is more likely to strip, if thin and brass.

Any other options I have not thought of?
thank you

1.5mm and 16 TPI are different enough (1.5 is 16.93 TPI) that it won't come very close to fitting a 16 TPI thread. I doubt you could get more than 2 or 3 turns of the thread of a 22 x 1.5 nut on a 7/8 - 16 thread.
How many threads do you have to to gauge? if it's more than 3 or 4, one should fit and one should not. Are you thread gages any good? Is the thread beat to hell?

CarlBoyd

 

[runswithsizzers]

1.5mm and 16 TPI are different enough (1.5 is 16.93 TPI) that it won't come very close to fitting a 16 TPI thread. I doubt you could get more than 2 or 3 turns of the thread of a 22 x 1.5 nut on a 7/8 - 16 thread.
How many threads do you have to to gauge? if it's more than 3 or 4, one should fit and one should not. Are you thread gages any good? Is the thread beat to hell?

CarlBoyd

Thanks for that. The total length of avilable male threads on the quill is about 7/16" (11mm). The threads appear to be in very good shape. I found a 7/8" 16 tpi part, and it will thread on all the way. Fit seems a little loose. I would show the part, but as a newbie, I don't think I can post links.

After I put the pulley block on the tapered quill, there are about 4-5 threads available (5/16" or 8mm).

I have ordered some left hand threaded nuts in the M22-1.5mm size for comparison. My thread gauges are nothing special. (If this is my 3rd post, I may be able to show the gauges in my next post?)

 

[runswithsizzers]

If I can link to a photo on my website <here> is a photo of my measuring tools - which will probably look very primitave compared to the cool gauges you all probably have.

And <this link> shows the 7/8" 16 tpi part I found at Grizzly. I will need to modify it so it will fit in the recess in the top of the pully block, but I think I can make this work - unless I like the fit of the metric nuts better.

Thanks again to all who replied for your patience and knowledge.

 

[deltap]

+1 for metric. Put a small flash light behind when using thread gauge and view from opposite side to check fit. Measure crest to crest with caliper and magnifying glass on as many threads as possible for pitch. Thread od should measure about .010" (.25mm) smaller on 22mm, a significant amount.

 

[rons]

Identify other fasteners on the machine. If a few are metric then you have your answer.

 

[michiganbuck]

If you had your location listed I would recommend suburban bolt Just north of Detroit.
586-775-8000

It is good for all members to post location..at least their state.

looks like 7//8-14 is more normal than 7/8 - 16

Easy enough just to make one. but if your lathe is down then you cant.

 

[stephen thomas]

I believe it is a requirement to post at least your state.
For all we know, you have excellent English but are posting from Bangladesh. (It happens)
You can consider this an informal warning that won't go on your permanent record ( (remember those?) if you get around to adjusting your profile.

If I get the thin brass nut, it might tolerate a misfit better than a thicker nut in hard steel, right? And brass would be less likely to damage the male threads on the spindle

Can i assume the pulley is driven by key or splines, and the nut just holds it down?
If so, absent access to machine tools, i like your plan.

Any other options I have not thought of?

Yes, you need a deeper cross section of friends. Always have a few that fight over who will get to impress the other with the quality and finess of their machine work, especially on simple shiny things like brass nuts.



smt

 

[Bill D]

My Jet Mill/drill made around 1977 in Taiwan uses USA size nuts and bolts. I was expecting them to be whitworth not 60 degrees.
Bill D

 

[michiganbuck]

a 16 thread about .0625" pitch and a 1.5 mm about .O590./.0591"
A difference of about .0035 . Seems if you have a jo block set/stack and a loop you may be able to eyeball the threads and make a determination. Certainly, if you go out 10 threads you should see the difference.
I think that would be about 15.9 mm and 15 mm even for the other.
Yes, check my numbers..

 

[Shipp]

If you had your location listed I would recommend suburban bolt Just north of Detroit.
586-775-8000

It is good for all members to post location..at least their state.

looks like 7//8-14 is more normal than 7/8 - 16

Easy enough just to make one. but if your lathe is down then you cant.

How do I make My location visible? I just joined and have had no luck with it.

 

[michiganbuck]

How do I make My location visible? I just joined and have had no luck with it.

Click on your name at the top right of the screen
Click Account details
put in your location

 

[Shipp]

Click on your name at the top right of the screen
Click Account details
put in your location

I totally missed the separate field for how I want my location to show up in posts, I just saw the areas required to make an account. Thanks

 

[neanderthal mach]

Your thread gauges look more than good enough for positively identifying that thread and I'd still use what you have even with my micrometers and thread wires. But if it really is 7/8" x 16 tpi and blowing up that catalog picture of Grizzly's, it literally shows just how poorly it's made. So no real surprise it's a loose fit as well. That picture seems like it's a cast iron and not cast steel part. If so and given it's absolute crap internal threads, I'd go easy with just how much tightening torque those female threads are going to withstand before failure. And the already sloppy fit just compounds the issue. Much better imo once the thread is 100% identified is finding the correct left hand steel nut. And a Taiwan made drill press doesn't always mean it's going be metric. It could be either or a combination of both. My Taiwan built Bridgeport clone has 100% imperial sized and threaded fastners on it.

 

[michiganbuck]

Would it be possible to turn down the thread to a smaller size and die cut a more standard thread..Here is a 3/4 20 left-hand die for a low price. If a 3/4 20 left nut cant be found the a 3/4-10.3/4-16.or a 5/8" something.

3/4" - 20 Left hand Thread Die 3/4 - 20 TPI [C1] | eBay

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a whole bunch of taps and dies.

Fractional High Speed Steel Left Hand Taps | Left Hand Dies

Victor Machinery's online store for taps and dies, cutting and measuring tools, machine shop supplies.

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