Jump to content

Banner.jpg.b89429c566825f6ab32bcafbada449c9.jpg

sw 1.25" ep holder, screw size?

sunshine185

Recommended Posts

sunshine185

sunshine185

Posted
Posted

Can anyone help? What is the thread size of the 2 eyepiece holder screws? I thought I would order some grub screws to hold my binoviewer, I thought they were m2 but the grub screws that arrived are tiny.either they have sent the wrong ones our I was wrong about the originals being m2.

Link to comment
Share on other sites
glowjet

glowjet

Posted
Posted

The 2mm you chose are far to small, I have checked a number of my accessories of different makes and the screws seem to be standardised as M4. If you look up a company called Boltmeup on Ebay you will find they have a tremendous stock of all types of stainless metric screws, including grub screws, they supply small quantities mostly post free, HTH :)

John.

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

Should those turn out not to fit you may find that they're some odd imperial size. I've just checked a couple of diagonals and they're M4, but I have some other bits that are #10-32 UNF.

James

Link to comment
Share on other sites
glowjet

glowjet

Posted
Posted

James could be right, but I think Sky Watcher are pretty much Metric, however, I fell into this trap with some USA kit, I thought it was Whitworth but it turned out they use UNC, but it is really confusing when you come to some original Chinese bits, as I did in the past, I think they make their own threads, well they would wouldn`t they :D

John.

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

The 4mm ones don't fit? That's a major pain in the derriere. These are the screws in the focuser that lock the eyepiece in place, yes? Is it obvious whether the grub screws are completely the wrong size, or is it more like the threads are the wrong pitch?

James

Link to comment
Share on other sites
AndyH

AndyH

Posted
Posted

Thnx James, I'm hoping the skywatcher focussers use standard m4 screws. If not, then I will look for those you mentioned, ta!

:(

The majority of diagonals/accessories I have and have had, use the following threads.....

M4, M3 or very rarely if from the States, either 6-32(metric o/d=3.5mm) or 8-32(metric o/d=4.2mm)

I highly doubt it's either of the latter imperial sizes. Probably M3?

Andy.

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

I have some from a finder that I think are probably 4-32, too. The major diameter is certainly correct within the tolerance of my Vernier calipers. I think an accurate measurement of existing screws might be the only way to resolve this one unless you want to end up with a dozen difference sizes of grub screw :)

James

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

*sigh* I am such a donkey sometimes :(

I have just remembered that I have the focuser from a Skywatcher 250P dob sitting here under my desk. The screws retaining the 2" to 1.25" reducer are definitely M4. The eyepiece retaining screws however are not. They could be M3, or they could be 4-32 UNF. I'll see if I can find an M3 screw in the workshop at lunchtime so I can test it.

James

Link to comment
Share on other sites
sunshine185

sunshine185

Posted
  • Author
Posted

That would be great, many thanks for taking the time out. Its the eyepiece retaining screws on the 1.25mm holder I need, I keep buying different screws but they don't fit, they don't cost much individually, but the way I'm going through them I could have afforded a new scope!

Link to comment
Share on other sites
coulthamst

coulthamst

Posted
Posted

I have just checked the eyepiece holder screws from a standard Skywatcher set against a metric tap and die set. Those fitted to the 1.25 holder are M3x0.5, whilst those fitted to the 2" holder are M4x0.7, in other words the standard metric threads. Hope this helps.

Jim.

Link to comment
Share on other sites
JamesF

JamesF

Posted
Posted

Oh, jolly. I've just tried a couple of M3x0.5 taps in mine and I wouldn't have said they were a good fit. I did find a screw that fitted in my father-in-law's large collection of what he claims are M3 screws, but that wouldn't fit an M3 die, and a nut that fitted the screw wouldn't fit an M3 tap either. I can't imagine why we'd have a collection of screws that were almost but not quite M3, so I think I'd have to go with Jim and assume the set of taps and dies I tried with are just rubbish.

James

Link to comment
Share on other sites
  • 1 month later...

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.