Thread size on the Elgeet 135/4.5 ?

I can't figure out what the thread is on the Elgeet 135/4.5. Does anyone know?

It seems to be 32 or 32.5mm (or so) and I can't tell if it's 0.75 or possibly even finer. Then again it might not be metric at all as 1 1/4"=31.75mm. There doesn't seem to be much info on these things so any advice would be appreciated.

Thanks
JJ

I’m unsure about the Elgleet lens, but the other US made enlarging lenses that I’ve examined use common fractional inch sizes and inch-based thread pitch.

For example, I have a 162mm f/4.5 Enlarging Raptar, it’s flange, as well as a flange only from a smaller Raptar of unknown focal length.

The 162 Raptar has mounting thread of 1.994” outside diameter. It appears to be 2” x 30 threads per inch 60° unified v-thread. The 30 tpi thread gage fits well, while no similar metric pitch fits properly.

The smaller Raptar flange has 1 3/8” diameter x 30 tpi 60° unified v-thread.

All of the US enlarging lenses I’ve examined are marked “Made in Rochester, NY”, so it’s not surprising if they used a common threading standard.

From your comments about the thread size, it’s likely 1.25” diameter x 30 tpi.

1.25” = 31.75mm, which is approximately your estimated diameter of 32mm to 32.5mm.

Given the scarcity of flanges in these sizes, it’s advisable to buy a lens if, and only if, the proper flange is included.

Thanks for your help. I'll try to get a 1.25" flange and see how that goes.

Ian C said:

...Given the scarcity of flanges in these sizes, it’s advisable to buy a lens if, and only if, the proper flange is included.

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Truer words were never been spoken!

JJ

The 1944 ASA standard specifications for photo equipment lens threads includes 1.25 inch and 30 TPI, but also states that other threads may be used.

Jim Jones said:

The 1944 ASA standard specifications for photo equipment lens threads includes 1.25 inch and 30 TPI, but also states that other threads may be used.

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Great! Thanks very much.

JJ