Boxford CUD cabinet screw sizes and threads

This topic has 8 replies, 7 voices, and was last updated 12 June 2026 at 16:21 by Speedy Builder5.

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12 June 2026 at 09:39 #851744
lucerne
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@lucerne
I’m trying to source some missing / ill fitting screws for my recently acquired CUD and wondering what the correct sizes are for these headstock cover plate and cabinet covers are?
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12 June 2026 at 10:02 #851747
alecs
Participant
@alecs
Possibly BA.

If you take out the existing ones and measure the TPI and diameter, you can cross check it with the online charts.
12 June 2026 at 10:29 #851748
lucerne
Participant
@lucerne
Thank you, I need to buy some magnifying glasses!
12 June 2026 at 11:41 #851771
Roderick Jenkins
Participant
@roderickjenkins93242
I have no particular knowledge of Boxford lathes but have noted that British industry went through a period of using Unified threads in the latter half of the 20th century before embracing the Metric system. I suggest it may be worth considering all possibilities.

Rod
12 June 2026 at 12:08 #851772
DC31k
Participant
@dc31k
Is it worth looking in the manual for the machine, at the parts list and exploded diagram? At worst, you will draw a blank.
12 June 2026 at 13:09 #851774
SillyOldDuffer
Moderator
@sillyoldduffer
BA is likely, but the age of the lathe (1950 – 1975) means they could also be BSF, BSW, UNC or UNF. Metric might have been used on late models, but unlikely. Even though the UK decided to go metric in 1963, and BA threads were declared obsolete in 1966, metric wasn’t widely used before about 1980. In 1950, when the Type C first appeared, a British maker would probably have gone for BA (which are excellent for small fasteners), except the UK decided to standardise on UN in 1949, and Denford might complied with that.

Best to measure threads – it’s a muddle. Even with a good eye it’s not always easy to identify a thread system, nor is it completely safe to rely on what individuals have today; they may have a variant. Therefore I suggest coughing up for a couple of thread gauge sets and a jewellers eye-piece.

Example from RDG, other vendors available!

Gauges are eliminate many mistakes and are quick and easy.

Whilst £16 might seem an expensive way of identifying a few nuts, they’re worth it in the long-run. Gauges save a lot of time and aggro. A man who has invested in a Boxford CUD is surely in it for the next 30 years! Though RDG sell a BA Gauge, you can probably manage without if money is short. If a thread doesn’t fit any of the above set, isn’t spaced at an integer TPI, and has a rounded look, it’s probably BA.

As a rule of thumb, expect to spend as much on tooling as you paid for the lathe! And then materials and consumables have to be paid for too!

Dave
12 June 2026 at 13:17 #851775
JasonB
Moderator
@jasonb
Join the Boxford Owners group, you will get a lot of info from there not just guesses at screw sizes

https://groups.io/g/BoxfordLathe-UserGroup

If they are ill fitting as you say then not much point in measuring them as ythey could well be the wrong ones.
12 June 2026 at 16:15 #851806
lucerne
Participant
@lucerne
On 12 June 2026 at 13:09 SillyOldDuffer Said:

BA is likely, but the age of the lathe (1950 – 1975) means they could also be BSF, BSW, UNC or UNF. Metric might have been used on late models, but unlikely. Even though the UK decided to go metric in 1963, and BA threads were declared obsolete in 1966, metric wasn’t widely used before about 1980. In 1950, when the Type C first appeared, a British maker would probably have gone for BA (which are excellent for small fasteners), except the UK decided to standardise on UN in 1949, and Denford might complied with that.

Best to measure threads – it’s a muddle. Even with a good eye it’s not always easy to identify a thread system, nor is it completely safe to rely on what individuals have today; they may have a variant. Therefore I suggest coughing up for a couple of thread gauge sets and a jewellers eye-piece.

Example from RDG, other vendors available!

Gauges are eliminate many mistakes and are quick and easy.

Whilst £16 might seem an expensive way of identifying a few nuts, they’re worth it in the long-run. Gauges save a lot of time and aggro. A man who has invested in a Boxford CUD is surely in it for the next 30 years! Though RDG sell a BA Gauge, you can probably manage without if money is short. If a thread doesn’t fit any of the above set, isn’t spaced at an integer TPI, and has a rounded look, it’s probably BA.

As a rule of thumb, expect to spend as much on tooling as you paid for the lathe! And then materials and consumables have to be paid for too!

Dave

Thanks, I’ve a whitworth / metric guage and one of the nut / screw beads with UN and metric, but obviously need one with BA, as I suspect thats what they are. The very small ones on the top plate are difficult to measure.

On 12 June 2026 at 13:17 JasonB Said:

Join the Boxford Owners group, you will get a lot of info from there not just guesses at screw sizes

https://groups.io/g/BoxfordLathe-UserGroup

If they are ill fitting as you say then not much point in measuring them as ythey could well be the wrong ones.

Yes, and measuring the holes has not been too successful so far. Thnaks for the link to the owners group, I’ll join now😊
12 June 2026 at 16:21 #851815
Speedy Builder5
Participant
@speedybuilder5
Place a ruler with fine graduations (Imperial or metric) on your print/scanner, photocopier etc then place the screw next to the rule. Select the highest magnification on your device and scan/print. You could also scan to your computer and enlarge the image on the screen.

Count the number of pitches per 1/10″ or 1/8″ for tpi or mm for pitch. Check diameter with a micrometer and then search the engineering tables etc. It’s good to do the research as next time you may have a better stab at determining thread sizes.

Remember that thread diameters in tables are theoretical and often manufactured threads will be a little smaller.
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