small baty bore gauge thread size?????

[jimmy bParticipant @jimmyb]

I've got a small "Baty" bore gauge, missing a probe.

[jimmy bParticipant @jimmyb]

[jimmy bParticipant @jimmyb]

I'm missing one of the probes. I thought i'd make them, but I'm really struggling identifying the thread.

The major is 3.49mm the minor (in the gauge) is 3.29mm and the pitch appears to be about 62 TPI, (.41mm pitch)

I've spent a good while trawling the internet and came up with nothing! the tpi/pitch is a best guess as there are only 2 or 3 threads to measure.

Does anyone have any info on the likely thread?

Thank you

Jim

[Mick B1Participant @mickb1]

When I worked at Baty in the mid-80s, all bore gauges were subbed out to a company called Knight's, but yours looks as if it pre-dates that. So far as I know they never had any proprietary threads.

M3,5 x 0,35 looks a possible candidate?

[jimmy bParticipant @jimmyb]

Posted by Mick B1 on 14/11/2017 10:17:27:

When I worked at Baty in the mid-80s, all bore gauges were subbed out to a company called Knight's, but yours looks as if it pre-dates that. So far as I know they never had any proprietary threads.

M3,5 x 0,35 looks a possible candidate?

Thanks for that.

Jim

[jason udallParticipant @jasonudall57142]

M3.5 as I call them pattres screw ( holds light switch face plate to the square back shell in electric fittings)..
Just a though if you have any about. .to trial fit. .
But from memory those are 0.5 pitch…

[jason udallParticipant @jasonudall57142]

Ok thats a bust..it appears pattress screws are 0.6 mm pitch

[Mick B1Participant @mickb1]

Posted by jason udall on 14/11/2017 17:10:05:
Ok thats a bust..it appears pattress screws are 0.6 mm pitch

That means they're probably standard M3,5 coarse. The 0,35 mm pitch is M3,5 fine.

[charadamParticipant @charadam]

Baty appear still to make your depth gauge, or something very similar

Perhaps an email to their tech info line?

https://www.bowersgroup.co.uk/media/wysiwyg/bore_gauges.pdf

[jimmy bParticipant @jimmyb]

I’m going to make some. I think I’ve worked out the gearbox. Just got to engage leadscrew and turn chuck ten times, to check my calculations.

Jim

[EmgeeParticipant @emgee]

Hi Jimmy

Checked mine on the magnifier and can confirm thread is M3.5 x .35, total spigot length inc thread is 1.9mm.

Emgee

[Howard LewisParticipant @howardlewis46836]

B A perhaps? Unless a special to Baty.

Howard

[duncan webster 1Participant @duncanwebster1]

nearest to 3.5 mm OD is 5 BA, but that is 0.59 pitch

[jimmy bParticipant @jimmyb]

Posted by Emgee on 14/11/2017 21:03:56:

Hi Jimmy

Checked mine on the magnifier and can confirm thread is M3.5 x .35, total spigot length inc thread is 1.9mm.

Emgee

Thank you for taking the time to check. It'll be a week before I get chance to try it, but, I will post a follow up.

At present the gauge goes up to about 11mm, I'm planning to make probes that will allow up to about 14mm to give a decent overlap with my "next" size up bore gauge. I figure I'll need 4 more steps…….

Jim

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