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GM8 DEC axis head... depth of blind holes for attaching saddle...

Bill Krosney All Messages By This Member #59514 Folks, Replacing the stock "short" Losmandy saddle on my GM811 with one of Stephen Pizzo's RAYOX saddles. The stock Losmandy saddle is mounted with two 1/4-20 socket head screws that extend 7/32" beneath the saddle and screw into the two tapped blind holes in the DEC axis head.?? Stephen supplies machine screws for mounting that extend 10/32" beneath the mounting plate and screw into the same holes.? They were too long and I couldn't snug the mounting plate down. Simple solution, just use shorter machine screws.? Yes, but since this ultimately is what holds the whole saddle/OTA onto the DEC axis, one wants to make sure it is solidly mounted. Stephen was a little surprised in that he hadn't had the issue raised before.? I contacted Losmandy and was told that nothing has really changed with those mounting holes for the saddle on a GM811 or GM8. I measured the depth of those blind holes and I get 9/32".? Or at least I know I engage 9/32" of thread before any screw bottoms out. Wondering, others out there with GM811 or GM8s, could you measure the depth of those blind holes for mounting the saddle and what do you get? Thanks... ... Bill
Brian Valente Member Profile All Messages By This Member #59515 开云体育 I wonder if that upgrade has primarily been purchased by G11 owners? ? ? ? Thanks ? Brian ? ? Brian Valente Brianvalentephotography.com ? toggle quoted message Show quoted text From: Losmandy_users@... [mailto:Losmandy_users@...] Sent: Thursday, November 9, 2017 10:30 AM To: Losmandy_users@... Subject: [Losmandy_users] GM8 DEC axis head... depth of blind holes for attaching saddle... ? ? Folks, ? Replacing the stock "short" Losmandy saddle on my GM811 with one of Stephen Pizzo's RAYOX saddles. ? The stock Losmandy saddle is mounted with two 1/4-20 socket head screws that extend 7/32" beneath the saddle and screw into the two tapped blind holes in the DEC axis head.?? ? Stephen supplies machine screws for mounting that extend 10/32" beneath the mounting plate and screw into the same holes.? They were too long and I couldn't snug the mounting plate down. ? Simple solution, just use shorter machine screws.? Yes, but since this ultimately is what holds the whole saddle/OTA onto the DEC axis, one wants to make sure it is solidly mounted. ? Stephen was a little surprised in that he hadn't had the issue raised before.? I contacted Losmandy and was told that nothing has really changed with those mounting holes for the saddle on a GM811 or GM8. ? I measured the depth of those blind holes and I get 9/32".? Or at least I know I engage 9/32" of thread before any screw bottoms out. ? Wondering, others out there with GM811 or GM8s, could you measure the depth of those blind holes for mounting the saddle and what do you get? ? Thanks... ? ... Bill
Chip Louie All Messages By This Member #59516 Hi Bill, Consider this upgrade carefully. The GM8's saddle may have been kept as short as possible for at least two reasons I can see.? First, mechanical clearance of the saddle. The standard Losmandy D and later D/V saddle's short overall length allow more RA travel before hitting the safety limiter when you consider the rotation of the DEC axis than if you had a longer wider saddle or a saddle with a taller clamping knob or clamping lever. For an imager this may be more important than a nicer saddle. Second,?the mount doesn't need more clamping surface area as the standard/DV saddle can probably safely carry double the rated 30lb. payload.? Additionally the 30lb. payload limitation of the GM8 mount precludes the need to hoist heavy OTAs into the saddle. For the cost of a Raynox saddle even as pretty as it is for about the same money I'd rather have Scott install the tucked motors on my GM8 AND add a pair of the new OPWs.?Just stating the obvious issues I see I'm certain there are other reasons I'm not aware of.? Cheers/Chip ?
Bill Krosney All Messages By This Member #59523 Good comments Chip, My unit is the GM811, so its "GM8" DEC axis?already has the tucked in motors (which I agree are very nice) and the new OPWs. Also I purchased the GM811 and had Scott put on the RA Ext kit.? Both for the ability to split the head for transport and packing but also to provide greater clearance. Once the saddle is mounted first order of business will be to verify what I have for mechanical clearance. Thanks... ... Bill
David Pickett All Messages By This Member #59524 At 15:56 10-11-17, bill.krosney@... [Losmandy_users] wrote: I had Scott put on the RA Ext kit. Both for the ability to split the head for transport and packing but also to provide greater clearance. This is a brilliant solution to reducing carrying weight, providing more clearance, and at the same time making it simple to remove/replace the DEC axis. David
Bill Krosney All Messages By This Member #59525 Still looking if someone can measure the depth of the threaded blind holes used to attached a saddle to the DEC head on any GM8 or GM811. Stephen Pizzo (good guy to deal with) had sold a number of his saddles to Losmandy owners (yes, there were G11 owners but I believe he was certain there were a number of GM8 owners).? No GM8 owners commented about the threaded fasteners he supplied as being too long.? Maybe they just used shorter fasteners, and didn't say anything, but I thought I'd follow up with other GM8/GM811 owners and see what was the typical. So if someone can post the thread engagement depth of these blind holes, I'd be most appreciative. Thanks... ... Bill
Chip Louie All Messages By This Member #59527 Hi Bill, My bad! The topic read GM8 and my brain left off the '11' in the body text. Yes, the GM811 will not have the same mechanical interference issues as a standard servomotor GM8 and the clearances will be almost the same as the full boat G11G which the Rayox works great with. I have a GM8 and G11. Scott rebuilt my G11 several months ago into a fully optioned G11G and I have also played with several different Rayox prototypes as they were developed over the last year into the extremely nice final production version saddle. Anyway, as I recall most fasteners in this class are good to go as long as you engage at least as many threads deep as the major diameter of the fastener so I think you should be okay to grind or file 20-30 thousandths off the end or just buy a shorter fastener. But if you are worried about maximum strength hand fit the screw to keep as many threads as possible but I would not worry about it too much as even a single standard quality Grade-5 1/4-20 fastener has a pretty high strength in shear which is how they are loaded in this application.? Chip ? .? ? ??
Bill Krosney All Messages By This Member #59529 Thanks Chip... ... Bill

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