An unusual thread size- Stanley 78 rebate plane

I have bought an old Stanley No 78 rebate plane. These were originally supplied with fences, which screw into the plane body, to set the width and depth of the rebate. Almost invariably one or the other is missing when they're sold on. In my case it's the depth stop.

I can machine a new stop. but I'm a bit foxed by the thread in the plane body where the stop screws on. Measuring the thread on the screw which fixes the width stop, which also fits the depth stop hole, it seems to be 3/16" x 28. But I can't find any standard thread with those dimensions. I could cut that on the lathe but it would be easier to buy a screw, or even a die if such things exist.

Any advice?

Robin,

How accurate are you able to measure it?

Could it be 7/32" x 28 ? BSF

Robin - they tend to use none standard threads.

It is a US thread form 60 degree. Stanley were notorious for using proprietry thread forms.

Do you know the age of the plane? Is it US or UK manufacture.

I have a No 78 plane at home but am away for a couple of days. Also have a No45 plane with one screw missing, the hole was also stripped.Found a screw 1/4-24. Standard size, fitted a helicoil, new screw was loose, but others the same size fittted.

Will check my 78 plane when I am home.

Peter

A quick search found taps and dies of that size on Tracy Tools in Whit form and also spare fence kits for this plane here
https://www.toolbank.com/19/p/SSP112714
Subject to confirmation it actually fits.

pgk

UNS #10-28 If I remember rightly which is 0.190" Martin King is your man hopefully he will see this post and confirm.

It's the depth stop not the fence that is needed and that has a thumb screw

Edited By JasonB on 30/11/2021 07:34:57

I recently sold a large assortment of Stanley and Record planes, dating from pre WW2 upto 50’s. When I went through them there were a few with missing handle screws. Having looked them up online I bought a set of bits from Amazon. From what I got I was able to get most planes back to working condition. There is a difference in thread size across the range of planes, I think the set of parts, studs, nuts etc, were 3/16BSW, but some of the tapped holes were larger. There is a lot of information out there on thread sizes on planes, but I get the impression there are differences maybe due to date or place of manufacture.

You even get it nowadays

I got some bearing pullers from the tools bit in TK-Max and a nut fell off one which the gremlins grabbed and hid

Not a problem says I, I'll put a 6mm on it

Except it wouldn't fit and even the stub thread looked not right

it was ~6.3mm, a 1/4 inch with an imperial thread

The Chinese will be doing USA market stuff and some of it ends up in Europe

Hi All,

Jason has it right. Depth stop uses a thumb screw not a cheese head.

Generally but NOT always Stanley seemed to use the odd number 32nd W sizes for most of their screws. (5,7 & 9)

For the USA made planes I think that Stanley used whatever they had lying around!

The 78's are notorious for being absent depth stops and fences are often broken which is why I snap them up whenever possible.

I am in the process of 3D printing a batch of 78 depth stops as we speak! I have been doing the fences for the 71 & 071 Router planes and they sell like hot cakes as the original items make outrageous amounts of money.

They are perfectly good for users even if "collectors" send me hate mail! (TRUE!)

Cheers, Martin

Ady refers to a thread as 'Imperial' but the implication of his comment is that this was a US standard thread.

In my view, the term 'imperial' means relating to an empire, and so covers Whitworth, BSF, etc, and not the American standards. This is because the US never had an empire but the UK did.

If I am wrong, please explain.

Cheers, Tim

Tim, Whilst accepting that this is not a forum for historical debate, and we can argue the semantics of the word, I would contend that America had, or even still has an empire, or at least imperial ambition. Looking at, for example, its conquest of the nations on the same continent from which it acquired what became the south western states and Pacific wars of the 19th and early 20th centuries in which it acquired such as the Philippines and Hawaii etc.. I am not sure if it imposed its industrial thread standards on these territories, I suppose it must have done in Texas, New Mexico and California etc., but you did at least ask someone to explain and I can recommend further reading on the subject if anyone so wishes, but I doubt that they will, LOL!

Edited By Chris Crew on 30/11/2021 11:41:57

Edited By Chris Crew on 30/11/2021 11:48:55

I've just measured the thumb screw on mine, which comes out as a slightly loose fit 0.179" x 28tpi which seems to confirm your readings.

You might get away with a Herbert type die head and 1BA chasers if you set it to cut a tad undersize, as 1BA is about 28.3 tpi

Bill

Edited By peak4 on 30/11/2021 12:59:41

This shows the usefulness of a lathe with threading, you can make pretty much any thread to order, I have made some mating threads which are made for the job, they are unique in size, I have no idea what size they are, but they work perfectly.

The duplicated thread now appears to be closed, so to repeat my answer here;
If you use your favourite search engine on "Stanley Plane Thread Sizes", there is a wealth of information, all concurring that it's a current non-standard size, some say 3/16"x28, others No.10x28, neither of which help you, because it's no longer a standard, if indeed it ever was one.

Easiest solution to me is to buy an M6 thumbscrew off eBay or similar, and turn off the thread, almost all the way to the top. The remaining bit will allow a nut to be Loctited on and turned down to form a collar.
The rest, when the thread has been turned off, is almost spot on size to cut a 28tpi thread.

(or, as mentioned previously, the thumbscrew on mine is a rattling good fit, so you might just get away with an undersized 1BA @ 28.3tpi)

When you've got those sussed, try Singer sewing Machine threads next, where you will find several 3/16"x28 were used..
https://www.singersewinginfo.co.uk/screw_threads

From the Singer tables and catalogues, it becomes obvious that this thread was used on several machines.
My own walking foot patcher is a 29K4, so quite old.
It's the only one for which I have parts manuals.
The two suitable candidates are screws 274 +locknut 1539, both of which seem to be unobtainable, or a 515 wingnut, also no longer listed anywhere.
See plates 1046 & 7742 of this pdf
https://www.universalsewing.com/images2/parts_lists/all/74nfn30o.pdf

There is another one which is used to lock the rotating head; on my machine, it shares the same thread size.
On later machines it comes up as a Singer part No. 109535 - SS535W, but I don't know if they changed the thread.

These are available from College Sewing, amongst others.
https://www.college-sewing.co.uk/ss535w-head-rev-bush-stop-thumb-singer.html
N.B. I don't know if it's the same thread, as no=one ever seems to publish the specs. but I suspect it is.

Bill

It used to be NS then changed to UNS as per my earlier post. The "Special" series were non preferred but did have standard pitch/dia combinations

Google will throw up several suppliers of #10-28 dies if you don't want to single point them

As for sewing machines there is a standard for those too

Edited By JasonB on 01/12/2021 14:12:00

When the thumbscrew on my Record version guide failed I used a spare screw from the front blade position. Not perfect as I now need to use a screwdriver.

My Stanley 50 plane lacked an adjusting thumbscrew, and I was able to borrow an example and make a replacement.

The thread is a standard #12 x 28 NF. I bought taps and a die from ebay for a modest sum, and still have them. If that is the thread you need I'm happy to negotiate a loan. Send me a PM if you're interested.

George

Apologies for the duplicated thread.

Thanks for replies - JasonB is right, as Martin confirms. I had measured 4.74 mm and assumed that was 3/16" - I was unaware of the existence of the UNS standard so was looking at UNC/UNF/Whit possibilities.

Although Tracy list 3/16" x 28 dies they are out of stock, and anyway £24 is a bit steep for a die which I will probably never use again. Other offerings for dies are the same sort of price. The plane cost me £15. I'll single point it.

Keith - nice idea, but the spare screw on the front of mine (Stanley, made in England) is 3/16 x 24tpi.

Martin - I'm very much a 'user' rather than a collector - it's a bit depressing to hear that you have suffered abuse just for restoring a function of an old tool. Nowt rummer than folk I suppose. If you have any printed stops not spoken for I might be interested. Machining the body of the stop is straightforward, but getting the V which holds the face of the stop parallel to the sole of the plane right might be more challenging.

Robin

Edited By Robin Graham on 02/12/2021 00:48:51

Robin, you have a PM!

Martin

There is currently a 78 fence rod for sale on ebay, £10.00 Buy it now