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9/16 nut help!

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Margaret Trelawny24/09/2023 14:58:53
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Frances IoM - I don’t have a thread gauge. I must get one. I am going by what the suppliers printed info/websites are telling me.

JasonB24/09/2023 15:12:21
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I'll check with Ketan tomorrow but I think what is on their site is the stud is threaded M14 x 1.5 at the top and will pass through the 9/16" dia hole "D" in the toolpost. ARC have a specific post stud to screw directly into the metric thread on the SC4 topslide and as all other threads on the lathe are metric they also specify a metric thread for the top.

Michael Gilligan24/09/2023 15:13:45
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Posted by Margaret Trelawny on 24/09/2023 14:46:36:

Guys, I’m getting more and more confused (doesn’t take much!)

As mentioned in my opening post - the arceuro 111 QCTP is supplied with (according to their catalogue) a flanged nut specified as 14mm (9/16 UNF).

The toolpost stud from LMS is specified on their website as having a 9/16-18 thread.

to recap - the nut supplied with the 111 QCTP (specified as 14mm (9/16 UNF) WON’T FIT this stud.

So if I buy a 9/16 UNF nut surely it’s going to be the same as the arceuro nut? Or am I missing something?

 

face 21 Thanks all

M

.

Well someone, somewhere, must be being ‘economical with the truth’

9/16” is 14.2875mm so that conversion is obviously ‘ish”

You do really need to measure these things

MichaelG.

.

Edit: __ as Jason says, the 9/16” would be a nice clearance hole for an M14 thread.

P.S. __ M14 x 1.5 is a very coarse pitch of thread compare with the other two you have mentioned.

Edited By Michael Gilligan on 24/09/2023 15:24:08

JasonB24/09/2023 15:19:19
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Michael as my post above Ketan is saying they supply a stud of 9/16" dia shank, top is reduced and theraded M14 x 1.5, bottom is reduced to 12mm and threaded M12 coarse.

As the hole in teh toolpost is 9/16 you want a nice close fitting 9/16" shud shank for repeatability.

No Porkies being told

Michael Gilligan24/09/2023 15:22:38
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I’m even more lost now than I thought I was crying 2

MichaelG.

.

secret

Edited By Michael Gilligan on 24/09/2023 15:25:04

Bill Phinn24/09/2023 15:28:39
1076 forum posts
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Posted by JasonB on 24/09/2023 15:19:19:

Michael as my post above Ketan is saying they supply a stud of 9/16" dia shank, top is reduced and theraded M14 x 1.5, bottom is reduced to 12mm and threaded M12 coarse.

As the hole in teh toolpost is 9/16 you want a nice close fitting 9/16" shud shank for repeatability.

No Porkies being told

The source of confusion, I think, Jason is this page, where the clearance diameter of D is given as 14mm and then qualified, in brackets, with the words "9/16" UNF stud" .

peak424/09/2023 15:37:30
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2207 forum posts
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Posted by Margaret Trelawny on 24/09/2023 14:46:36:

Guys, I’m getting more and more confused (doesn’t take much!)

As mentioned in my opening post - the arceuro 111 QCTP is supplied with (according to their catalogue) a flanged nut specified as 14mm (9/16 UNF).

The toolpost stud from LMS is specified on their website as having a 9/16-18 thread.

to recap - the nut supplied with the 111 QCTP
(specified as 14mm **(9/16 UNF)** WON’T FIT this stud.

So if I buy a 9/16 UNF nut surely it’s going to be the same as the arceuro nut? Or am I missing something?

 

face 21 Thanks all

M

Margaret, sorry if I didn't word my previous reply clearly enough.
From what I can make out, and please correct me if I'm wrong, you have a 111 QC toolpost from Ketan, but are using a stud from LMS.

From the link I supplied for the ArcEuro toolpost, the thread specified in their catalogue is M14x1.5mm
This is not 9/16" UNF as you state in brackets.

I believe you have sourced an LMS stud from the USA to replace the ArcEuro one
This is a different thread and is 9/16" UNF, so you need a nut to match the specific stud you are using.

The toolpost might possibly accept either stud, but the nut is specific to the stud, not the toolpost

If you do actually have an LMS stud, you seems to need a 9/16" UNF nut
If you are using an ArcEuro stud you need an M14x1.5mm nut.

Bill

Edited By peak4 on 24/09/2023 15:38:23

JasonB24/09/2023 15:41:02
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As I said I think it is 14mm x 1.5 on th etop of a 9/16" shank to match 9/16" hole in post. If not it's 14mm all the way to the bottom shoulder and a looser fit in the hole

111 stud thread.jpg

Michael Gilligan24/09/2023 15:43:02
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Posted by Bill Phinn on 24/09/2023 15:28:39:

.

[…]

The source of confusion, I think, Jason is this page, where the clearance diameter of D is given as 14mm and then qualified, in brackets, with the words "9/16" UNF stud" .

.

Thanks for posting that link, Bill yes

… I can feel my sanity slowly creeping back.

MichaelG.

Nick Wheeler24/09/2023 15:53:38
1227 forum posts
101 photos
Posted by Michael Gilligan on 24/09/2023 15:22:38:

I’m even more lost now than I thought I was crying 2

MichaelG.

Me too.

If the available stud screws into the lathe, fits inside the tool post and projects from the top, then use a nut that fits the stud with a couple of washers to spread the load.

The post won't be centred on the stud which isn't ideal.

But you can now use the lathe to make a stepped washer that fits inside the bore of the post and you're done. M8 stud inside a 14mm bore - think that's what you have - gives plenty of space for this.

That's a couple of minutes work, but could be better; I would make a complete new nut with a permanently attached handle so the post can be loosened without the use of a spanner. Like this:

toolpost.jpg

That's how the Myford size Dickson toolpost is fitted to my WM250

Margaret Trelawny24/09/2023 16:01:54
100 forum posts
42 photos

img_5768.jpegimg_5767.jpegimg_5766.jpegHi Bill and chaps,

ok, so the attached photos show the new ‘sleeve’ stud from LMS in place.

the second shot shows the nut sitting on top - it won’t turn anymore than this.

also shown are the arceuro catalogue page which gives the spec of the 111 QCTP and lastly, the LMS webpage spec for the ‘sleeve’ stud…

Margaret Trelawny24/09/2023 16:03:08
100 forum posts
42 photos

img_5765.jpegNo idea why the page doesn’t post the pics in sequence either!

here is the ‘sleeve’ toolpost in place….

Nicholas Farr24/09/2023 16:22:37
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Posted by Margaret Trelawny on 24/09/2023 14:15:04:

Nicholas - thanks for the link to Spalding.

are these 9/16-18? Seems to suggest so in the spec if I am reading it corrext. Apologies for the seemingly naieve reponse but I have no engineering knowledge at all.

**LINK**

many thanks

M

Hi Margaret, 9/16 UNF is 18 TPI and these are in the UNF list, you will find these in the ebay link above, that MichaelG has posted, and you would be able to buy just two instead of a minimum of five on their web site, but cost more, but at least they do have free posting on ebay.

Regards Nick.

peak424/09/2023 16:23:44
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Margaret, right, now I understand your confusion.
Where did the middle screenshot of the three in your second to last post come from?
It's misleading in its presentation.

Out of curiosity, where did you source your toolpost, we know the stud came from LMS?

I believe the 111 toolpost and the stud details you have circled, in column D, is likely to lead to a misunderstanding
That toolpost will take either a M14x1.5mm stud with the appropriate nut, **OR** a slightly larger diameter 9/16" UNF one.
The nuts are not interchangeable between studs.

The model 100 in row A above may **ONLY** take a 14mm stud as it likely has a smaller hole, so 9/16" won't fit.

Bill

 

Edited By peak4 on 24/09/2023 16:30:47

Margaret Trelawny24/09/2023 16:26:53
100 forum posts
42 photos

Hey Bill.

Lol - glad I am not going mad!

 

the middle pic is from the arceuro printed catalogue.

 

best wishes

M

Edited By Margaret Trelawny on 24/09/2023 16:27:11

Edited By Margaret Trelawny on 24/09/2023 16:27:42

Margaret Trelawny24/09/2023 16:28:12
100 forum posts
42 photos

Thanks Nick

SillyOldDuffer24/09/2023 16:33:05
10668 forum posts
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Posted by Margaret Trelawny on 24/09/2023 14:46:36:

Guys, I’m getting more and more confused (doesn’t take much!)

As mentioned in my opening post - the arceuro 111 QCTP is supplied with (according to their catalogue) a flanged nut specified as 14mm (9/16 UNF).

The toolpost stud from LMS is specified on their website as having a 9/16-18 thread.

to recap - the nut supplied with the 111 QCTP (specified as 14mm (9/16 UNF) WON’T FIT this stud.

So if I buy a 9/16 UNF nut surely it’s going to be the same as the arceuro nut? Or am I missing something?

face 21 Thanks all

M

I can't see where ArcEuro say their nut is both 14mm and 9/16 UNF? I did find 'The Model 100/111 Tool Post Stud is threaded M14x1.5 at the top with a ø14mm shank to match the tool post bore and is threaded M12 at the bottom for the SC4 lathe’s compound slide.' in their 111 for SC4 fitting instructions,

I think root cause was buying a post from Little Machine Shop in the US. American customers would expect the 111 QCTP to be fitted with a UNF nut. Not so in Europe. Here, metric is far more common than UNF, making it likely ArcEuro sell the same QCTP apart from the post having a metric thread (M14x1.5) Not normally a problem unless a European customer buys from the US or vice versa.

In the event no-one is able to gift a 9/16" UNF from their junkbox, I'd buy a full nut from a UK supplier and put a washer under it. (£2.55 from Westfield) When the tool post is working, not too difficult to make a flanged 9/16" UNF on the lathe.

Dave

peak424/09/2023 17:13:24
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OK, I think I've got there folk (maybe )

For whatever reason related to Margaret's lathe, the studs supplied by Ketan don't fit.
She needed a stud where one end is internally threaded M8 and was able to obtain one from LMS
https://littlemachineshop.com/products/product_view.php?ProductID=3712&category=521186833

This has an external 9/16" UNF thread, and needs the appropriate nut.

The ArcEuro web site and paper catalogue differ slightly in their presentation, but the column which specifies the stud size/hole diameter is labelled as øD where the ø refers to the hole diameter's nominal size.

On the web site, The 101 toolpost says øD 14mm (M14x1.5mm Stud)

But for the 111 toolpost says øD 14mm (9/16" UNF Stud)

i.e. same hole diameter, but just mentions a different stud; likely either will fit.

Ketan supplies a stud suitable for an SC4 lathe, but that has an M12 lower thread and an M14x1.5mm top thread
https://www.arceurotrade.co.uk/Catalogue/Machines-Accessories/Lathe-Accessories/Tool-Posts/Model-100111-Tool-Post-Stud-and-Nut-for-SC4-Lathe

I'm guessing this was the source for the nut which doesn't fit Margaret's LMS stud from the US.

It looks like the ArcEuro stud wouldn't fit Margaret's lathe, hence ordering a suitable one, (threaded M8 internally), from abroad, which unfortunately didn't come complete with a suitable nut, though for a US buyer, they are readily available.

The end result is that Margaret just needs a 9/16" UNF nut and washer, which should be easily available.
9/16" UNF flange nuts seem hard to find in the UK, and I've tried quite hard; up to 1/2" do seem to be around.

The only possibility I did find for an off-the-shelf flange nut was a wheel nut for some very specific American cars, such as a Dodge RAM; most UK 9/16" UNF wheel/lug nuts have tapered or spherical seats, rather than a plain flange washer, so would be unsuitable.

Bill

JasonB24/09/2023 18:18:02
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Final option would be to buy a cheap 9/16" nut so the lathe can be used then machine off the M12 thread from the ARC stud, drill & tap M8 and then fit the ARC stud in place of the LMS one and use the flanged ARC nut.

Pete24/09/2023 19:51:01
128 forum posts

If I was in the same situation you are Margaret, that stud would have been a simple to replace lathe project. I'd do it between centers just to keep everything a bit more concentric. Obviously metric is now the much more prevalent standard in the UK. And whatever the female threads that have been tapped through the top slide for the bottom of the stud you'd of course have to match those. At the top you can cut whatever thread pitch and size is the most standard and available where ever anyone is as long as your lathe is capable of cutting threads in either the metric or imperial pitch you want to use.

Due to the number of various thread standards used over the last 100 plus years, with a lot still in use and some obsolete or almost so today, I'd agree and it can be a bit confusing. I've also read and for various manufacturing purposes, there's over 600 thread sizes, thread forms, pitches, flank angles, root and crest shapes that are common or at least still being used today. And yes having a couple of those different metric, imperial or possibly a few others such as BA depending on exactly what your doing, those thread gauges are almost a requirement for most of us. There's also a fairly easy method of substituting almost any thread pitch standard to something else that is convenient with a online search for the dimensions. Old Model Engineering drawings would be a prime example. Something like those BA threads to metric or imperial, just look up the recommended tap drill size for whatever size and thread pitch is used on the drawing, then find a tap drill chart for the thread pitch standard you want to use for the fine / course thread pitch you have available that would be closely comparable to the drawings tap drill size and just use that. The very small sizes such as 9BA -16BA could be difficult and probably expensive to replicate with either metric of imperial. Think about it this way, any of those metric and imperial thread pitches were standardized for the expected use while still being adequate for strength. Since either still has to do the same job in whatever size and pitch they are, there sizes are quite comparable to each other. Only the diameters, TPI or threads per MM are just slightly different between the two systems. So for what almost any of us are doing, then the substitution method I mentioned will work fine. For very high strength and safety critical items, without question proper engineering data and high grade screws and/or nuts would still be the safest method. And for some such as the Model Engineering 32 and 40 TPI thread series, it's of course not quite as easy. So those might also be necessary. But again it just depends on what your doing.

For myself and in North America, our Machinery's Handbook would be pretty much the usual source for most machining standards. And it has about everything I might need, especially so for threads. I've heard but don't actually know the Zeus black book of standards that seem to be common in the UK and Europe are comparable and possibly even better for some topics. Yes most or maybe all of that information could be found online and for free with enough searching, but it's not convenient or all in one place. And if that Zeus information is anything like what I'm using, then it should greatly simplify anyone's understanding about threads and a whole lot more. Online forum posts or even videos simply can't provide the same amount of detail for obvious reasons.

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