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Equipment Discussions >> Mounts

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langejcarl
sage
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Reged: 01/05/05

Loc: Michigan USA
Dovetail Attachment new
      #3592917 - 01/30/10 08:26 AM

I have an 8 inch solid aluminum dovetail bar attached by cap screws to tube rings. I have a couple of questions. Do most people simply attach metal to metal? Do any of you put cork or rubber gasket material between the bar and the rings? Do any of you use washers between the bar and the rings? If so, regular cut washers or lock washers? Finally, do any of you place regular or lock washers between the cap screw head and the bar?

Thanks.


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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: Dovetail Attachment new [Re: langejcarl]
      #3592995 - 01/30/10 09:41 AM

Metal to metal, with nothing in between. You want as much surface area between the bar and rings as possible. Washers or cork would diminish this.

Washers under the head of the bolt or nuts are fine, they prevent any gouging of the aluminum used in the bars.


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Doug D.
Carpal Tunnel
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Reged: 08/23/05

Loc: Virginia
Re: Dovetail Attachment new [Re: mclewis1]
      #3593013 - 01/30/10 09:51 AM

I sometimes use washers for a couple reasons - e.g., because bolts are a tad too long to seat tightly or if I need clearance of dewshield with the bar. In these cases I'm using washers for spacers only and I haven't ever felt I needed to use lock washers.

If using cork or other soft materials you can introduce some flexure - if imaging that is of course bad...


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langejcarl
sage
*****

Reged: 01/05/05

Loc: Michigan USA
Re: Dovetail Attachment new [Re: langejcarl]
      #3595043 - 01/31/10 07:48 AM

I have a follow up question. If I mount the dovetail bar to the center holes on the tube rings the screws are a little long and I could damage the OTA. of course I could get shorter screws, but does it matter if I mount the bar to the top or bottom holes in the tube rings so that the scope rides a little higher or a little lower? The metal of the rings is thicker at those points such that the screws won't go through to the OTA.

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BlueGrass
Carpal Tunnel
*****

Reged: 07/25/09

Loc: Wasatch Front, UT
Re: Dovetail Attachment [Re: langejcarl]
      #3595257 - 01/31/10 10:59 AM

If at all possible, use the correct length screw. I get all my 1/4 20 screws at Lowes. They have a good selection. Using the right screw means you don't have to worry about running them through the rings, damaging the felt or the OTA.

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