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Bolt size in old Ken Novak 4inch secondary holder

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#1 Gert

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Posted 24 June 2019 - 01:19 AM

Hello All,

Does anybody know the bolt size and pitch of the colimation bolts in the old Ken Novak secondary cell?

Novak_Secondary_txt.jpg

Why am I asking such a dumb question? This is our club scope which is at a site 2hrs away from me. I would like to know the bolts size without having to drive there, then drive to the hardware store and then drive there again to install new ones with hex socket heads, or knobs.

Any help is appreciated.

Thanks & Clear Skies,
Gert

Edited by Gert, 24 June 2019 - 01:55 PM.


#2 ngc7319_20

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Posted 24 June 2019 - 01:39 AM

My 1.875" Novak holder uses 8-32 x 5/8" long screws (length of threaded section, not total length of screw).  As best I can measure on your photo, the screws are exactly the same as mine.  Novak was big on commonality between products, so its no surprise they would be the same.  You can go long on the screws and it wont hurt anything -- they just thread up into the diagonal holder.  3/4" long is a more standard size.  

 

Probably a bag of 5 screws at Home Depot will be under $1.  You could pick up some 10-24 x 3/4" long and 10-32 x 3/4" long for extra insurance, but I'm 99% sure they will be 8-32.

 

Although I notice your holder looks modified, so maybe going long is a bad idea.  Might hit the glass on the right side of holder in the photo.  Maybe take a file with you in case you get into trouble on the length.

 

It looks like one of the screws is right up against a spider vane.  So knobs is probably not going to work.  Hex socket head (Allen wrench) will probably be fine.


Edited by ngc7319_20, 24 June 2019 - 01:50 AM.

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#3 Gert

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Posted 26 June 2019 - 01:28 AM

Thanks ngc7319_20,

 

I've bought a few choices of 8-32 and 10-24 bolts of various length in the hardware store and will try them out. Our cell is for the 4inch secondary so maybe the bolts are larger. But just from memory I would say they're smaller than 1/4-20.

 

Thanks & Clear Skies,

Gert



#4 ngc7319_20

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Posted 26 June 2019 - 03:57 AM

 

I've bought a few choices of 8-32 and 10-24 bolts of various length in the hardware store and will try them out. Our cell is for the 4inch secondary so maybe the bolts are larger. But just from memory I would say they're smaller than 1/4-20.

 

Since I knew your diagonal was 4", I could calculate the size of the screw heads in your picture, and they came out 0.28" +/- 0.02".  My Novak 8-32 x 5/8 screw heads are 0.30" so I am pretty sure they will be the same size.  Cheers!




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