I'm always asking about imperial threads

I have Record 077 bullnose plane, I'm mainly a woodworker, but I have mislaid a screw that holds the nose on. As I'm in Italy I cant pop out and try different screw sizes as everything is metric.

1/4" BSW 20 will only start to screw in. M6 x 1 will screw in but is far too lose.

What other 1/4" options are there?

Would 1/4" 28 be close to M6x1?

Edited By pgrbff on 15/10/2022 10:51:44

Record plane, have a look here, 7/32-20 BSW, I think that’s what it says.

I did have a look on there but I didn't find the screw size. I'll have another look. Thanks

This is a link for Record planes that was recently posted on MEW.

**LINK**

The bolt that holds the front knob is 7/32"- 20Tpi Whitworth

(beat me to it ! But i doubt that you will find a metric screw that fits. 7/32" = 5.56mm)

Edited By Paul Lousick on 15/10/2022 11:10:39

Can't get link to work

If a M6 screw is loose then a 7/32" screw will be even looser. Try 1/4" BSF, at 26tpi it is close to the 1mm pitch of M6 screws.

Andrew

One 1/4" x 3/8" posted to Italy, £16.

Try finding someone in Italy who works on or sells bits for old British motorbikes or cars. They all used BSF.

It's hard to explain but culturally Italy is very different on many levels, there really isn't a DIY culture. Italians even have special agencies that apply for driving licences and passports.

No-one would apply for their own driving licence.

pgrbff, I hope this post will display a link to my favourite very comprehensive go-to Thread size chart for you.

According to this chart...7/32" BSW would be 24TPI...emphasis on the S for standard. Paul, that's a great link to the Record Plane details, and they do only say 7/32 x 20 witworth form, i.e. not standard.

I suggest you do oversize, very slightly to 1/4", but being such small increase in diameter, stick with the 20 TPI options so you can 'stay in the groove' as the disk jockeys say. 1/4" UNC should be easy to get a tap and a bolt for.

Good luck, Allan

Normally with these almost 1/4 BSF, almost M6 issues on British made things the culprit turns out to be OBA.

Same nominal diameter as M6, same thread pitch for all practical purposes but different thread form. Touch smaller than 1/4 BSF, screws in just fine but pullout force is about 1/4 of what it should be!

Clive

One of the above links to the article about Record planes seems to be dodgy; this one works OK
https://recordhandplanes.com/parts-and-sizes.html

For further interest, and to add to your bookmarks and downloads, see these two articles from The Traditional Tools Group
https://www.tttg.org.au/

Part 1 discusses threads in general, particularly with reference to Stanley planes.
https://www.tttg.org.au/Content/Stanley%20Planes%20and%20Screw%20Threads%20-%20Part%201.pdf

Part 2 amongst other things , refers specifically to the No.12-20 thread
https://tttg.org.au/Content/Docs/Articles/Stanley-Planes-and-Screw-Threads-Part-2.pdf

Bill

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Perhaps unsurprising … Unfortunately, Paul has linked to his F drive :

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MichaelG.

I think you mean the 077A which has the removable front and adjustable mouth.

From memory, my screw is 1/4 BSF.

PS Just checked only to be reminded that my plane is the similar 311 combination version; FWIW, its screw is indeed 1/4 BSF.

Edited By ega on 15/10/2022 17:23:59

Edited By ega on 15/10/2022 17:42:20

i have often wondered why the plane makers used the thread sizes that they did, especially the none standard sizes. Sadly I suspect that like the reasoning behind number drill sizes the reasoning has been lost to history. Don't always assume that sizes given are the same now, with an old plane someone could have retapped to replace a lost screw with a more common size. Something that I have done myself to get a tool quickly back in use. Having said that whenever I get the chance I add to my collection of different sized nuts, bolts and screws.

I've got a tin full of 1/4 bsf screws, I'd happily post one to you, but since Brexit that is not at all easy, all sorts of customs issues. Can't send anything to my nieces in Germany, and believe me I've tried.

I've got one of these. I've had it from new.

Here's the screw:

Note the wear at the tip - the diameter varies from 6.02mm to 6.14mm towards the head. An M6 screw is very loose in the plane hole but a 1/4" BSF goes very stiff after about 5 turns. The screw, like the plane is plated. Anyway, the image is here if anybody fancies a bit of photgrammetry.

Rod

Edited By Roderick Jenkins on 15/10/2022 21:23:11

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Nice straight image, Rod

This should be enough to get people started:

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Just print it, and get to work with the measuring-stick and calculator

MichaelG.

Looking at the wear on that screw, and noting Rod’s comment about BSF going tight … I wonder if the tapped hole is tapered

My guess is that the plane-maker didn’t use a bottoming tap.

MichaelG.

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Edit: __ My own example of that plane [also purchased new] was quite poorly made in some areas

Edited By Michael Gilligan on 16/10/2022 10:23:16

1/4-26 on newish(70’s) 077 and much older 311.