Common Astro Equipment thread sizes

[wasyoungonce (Brendan)]

Thanks Simon

I also noted the discrepancy between the M48 filter thread's pitch in the list but left it till I could sort it. From what I know M48 is .75 pitch but I'll do some more searching on this.

There are a myriad of threads that everyone at one stage will need info on. So this is a "work in progress" I'm afraid.

I also only updated this was I am thinking of doing a 50mm finder guide-scope and wanted to know the rear internal thread. Every search I did found new and more info....just gathered momentum so just adding to Doug's thread.

[Astro_Bot]

Meade SCT (or ACF) casing screws:

UNC #8-32, length 3/8", but if securing a finder base, I recommend 5/8" length.

[wasyoungonce (Brendan)]

Originally Posted by niko

Brendan,

please provide thread size and pitch for head securing device!



niko

Sorry the bolts are still embedded..... cannot remove them otherwise me head'll fall off!

[MrB (Simon)]

Great... while removing the MPCC's T2 nosepiece to re-measure, I just planted a nice big fat greasy thumbprint on the rear element!

I really need to buy a set of soft cotton cloves, saw them at the local library recently and thought 'hmmm what did I need those for? oh well, will buy them when I remember'
That'll learn me!

[wasyoungonce (Brendan)]

Thanks Gents making changes now and will repost list ASAP.

Simon sorry...I didn't want people to take things apart....it's just some people know or have been thru these hoops before and may have inspiring info...sorry for the finger prints.

There are so many differing threads is impractical to list them all...especially us some US companies offer metric and imperial (like thumbscrews) and in general the USA will never change to metric.

[MrB (Simon)]

Originally Posted by wasyoungonce

Simon sorry...I didn't want people to take things apart....it's just some people know or have been thru these hoops before and may have inspiring info...sorry for the finger prints.

Hah no worries, it was done on my own volition, spurred by curiosity. The nosepiece is designed to be removed when not using the T-ring.
It's my own fault and carelessness for the thumb print.
It was actually a reflex action, the ring dropped as it unscrewed and I instinctively moved to catch it and that's when my thumb planted nicely on the element... grrrrr.

[wasyoungonce (Brendan)]

Ver 1.1 of the threads with new info.

Need to confirm:
1. If M48 filters are .75 or .6mm pitch or both are available.
2. If EQ6 (NEQ6) alt adj bolt (M10) is 1.5mm pitch or 1.25mm or...whatever.

Any other threads others have come across that someone may need to know about in the future.

Many thanks to all.

[MrB (Simon)]

Originally Posted by wasyoungonce

2. If EQ6 (NEQ6) alt adj bolt (M10) is 1.5mm pitch or 1.25mm or...whatever.

My early EQ6pro has M10 x 1.5 for both Alt and Az bolts. Can't speak for newer models.

[wasyoungonce (Brendan)]

Thanks Simon...will be updated in next version.

[brian nordstrom (As avatar)]

Zeiss visual back , M44x1 .
Brian.

[wasyoungonce (Brendan)]

Thanks gents and all

Ver 1.2 of the threads data.

Just want to confirm if OTA clam rings mounting threads are 1/4" x 20tpi with most OEMs? I have read WO has some at 6mm threads but am unsure on this.

[LewisM]

Some Vixen threads:
Standard drawtube, as already mentioned is M60 x 0.75
Older focal reducers- back side attaching to camera or diagonal: M43 x 0.75
Some step-down adapters and rotating rings use M53 x 0.75

Having an adapter made right now to go from an older Vixen focal reducer to a T2, and having it rotate as well for camera orientation. Will do pictures when Hugh finishes

[wasyoungonce (Brendan)]

Thanks will update soon

[Grendel (Peter)]

the vixen 1 1/4" back that replaces the .965" back on old japanese scopes is a M36.0 x 1.0 male thread
Grendel

[wasyoungonce (Brendan)]

Thanks put in for next update

[tferrari (Canada)]

We really need to resurrect this thread. This was very helpful.

Also - we never figured out if the 2" filter M48 thread is 0.6TPI or 0.75TPI

[wasyoungonce (Brendan)]

Thanks, on the spreadsheet I annotated (in a dialogue box) that M48 can be .6 or .75 pitch.

[bobzeq25 (Bob)]

If you Google M48 0.6 and M48 0.75, you will rapidly come to the conclusion that the latter is correct.

[OzEclipse (Joe Cali)]

Originally Posted by tferrari

We really need to resurrect this thread. This was very helpful.

I asked Mike Salway to make this thread a sticky so it remains easy to find.
Joe

[RobF (Rob)]

Bump. Wish I'd paid more attention to the sticky threads