Calling all Edmund 8" grey Gem scope info
Posted 19 June 2018 - 05:32 PM
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Posted 19 June 2018 - 05:45 PM
Fun with numbers: How many allen bolts in the cap and LAT lever arm?
All the bolts in the pier cap and latitude lever arm, without exception, are 5/16 NC stainless allen bolts. They all appear the same in the pictures. Each picture has multiple bolts not visible, that can be seen in the other picture. The two pictures show ALL bolts in the cap and lever arm. How many bolts are there?
By the way, it's not the stock factory number, ignore the two hex head bolts in the RA housing.
Several of the original set screws were cracked at the hex corners, one fell apart by itself. The set screws were abused, ugly, barbaric, and all in dire need of replacement. I like the new look.
Edited by apfever, 19 June 2018 - 05:59 PM.
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Posted 07 November 2018 - 08:53 PM
I put this together Monday after figuring out this little entry here:
I then found two issues. The first is the setting circles, which is a stopping point. I've looked around the web quite a bit, which pulled up old forgotten pictures I took of this scope too, and I have no idea what Edmund did for the factory installed setting circles. It seems Edmund did not even include circles in many cases, and most pictures didn't show any at all. The installed DEC circle here won't work in this position as the DEC lock is trapped. The circle would have to be much lower. I'd like to know how Edmund held the circles in place. Did they use a stop collar on each side, or just a rubber bushing? A spacer?
The RA circle goes on the machined area of the RA housing, just under the pointer. I don't know what Edmund used on each side, but there must have been something. The 6" uses a rubber ring on each side but the 8" machined area is 1/2" wide. I can cut rubber rings, made plenty of those to original configurations. Any identification of original ring installation would be greatly appreciated. The DEC circle is still on the kitchen counter waiting.
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Posted 07 November 2018 - 08:57 PM
Best mount i ever had. Smooth as milk and silk. No darn drives and clutches to add slop.
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Posted 07 November 2018 - 09:13 PM
Second issue is that I didn't have a stop collar (shaft collar) to hold the DEC shaft and saddle in place. The entire assembly could fall out during a flip. I picked up an order from Grainger this afternoon. It's a double split stop collar so no more set screw. I soooooo tired of shaft set screws, even with the proverbial super light rounding and polish. Soooooo tired of set screws. (how tired are you?) I'm more weary of set screws than a lot of the repetitive daily dribble blabber in this forum. This one worked great and I'll be getting a few more. The double split allows it to be removed without having to strip the shaft to slide it off. They run about $10 from any source in regular steel compared to about 4 or 5 dollars for a regular cheap solid set screw type, for a 1.5" bore. I'd like to put one on each side of the setting circle but that does start to add up since I can't just butt up against the shaft holder shown. I could use a sleeve and washer system with a rubber ring on each side. The hole in the circle is already a light push fit. Ebay has some 2 pack and 4 pack double split sets that get down to about $7 or $8 per collar.
I have a third needle bearing and race assembly that I bought just for the bottom of the DEC shaft. However, this is almost always not under any load unless you flip in RA. I used an original Teflon washer (white thing) instead and kept the bearing assembly sealed in the box for now.
Edited by apfever, 07 November 2018 - 09:17 PM.
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Posted 07 November 2018 - 09:13 PM
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Posted 07 November 2018 - 09:35 PM
If the build is similar to the 1" mount, the setting circles may be set between two pieces of rubber o rings.
You may be able to see the black rubber rings.
Edited by Garyth64, 07 November 2018 - 09:36 PM.
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Posted 07 November 2018 - 09:40 PM
It's getting a drive. I have an original. I was thinking of doing the drive with a quick release to allow for the show off slip slide magnetic type fluid suspension of the shafts. I'll be honest. With the needle thrust bearings and a 'dry' Teflon lube, the saddle sits there and spins circles with a flick of one finger. It's enough to look really weird. The assembly as shown is just slightly heavier with torque on the shaft side of the saddle. By turning it sideways and letting it go, the RA shaft swings back and forth with pendulum motion. It's all freaky to watch and feel. Video time but I don't do that stuff. Have to watch that the saddle doesn't hit the pier during play. The needle thrust bearings should have a lube of some kind. They have a numerical flaw that requires some slippage instead of true roll. True ball thrust bearings were too thick.
The Teflon is attached to the RA shaft and spins in the housing. This allows it to be an easy removal and re install for getting the original setting circle on for a photo. I won't keep the setting circles on for most purposes as they are too susceptible to damage. Clamp collars play into that.
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Posted 07 November 2018 - 09:57 PM
I have the original type rubber for those rings and I've made the flat ring washers many times using a double circle cutter on a drill press. It's a little tricky. I make extras when I do and I'd send you a set if you want. The original rubber is meshed reinforced. I make them a very thin hair larger in outside diameter and they don't cover any print on the circles. The machined width on the 6" mount is about 1/4" and the flat rubber washers are 1/8". The machined section of the 8" mount is 1/2" which would require two 1/4" rubber washers. I'm just not sure how Edmund did it. I'd like to know what came from the factory even if I decide to not duplicate it exactly. I likely will, then remove and store the system for safe keeping.
Here, go down to post #43
You can see them installed in post #47
Edited by apfever, 07 November 2018 - 10:05 PM.
Posted 07 November 2018 - 10:13 PM
Robert......um...you have a lot of stuff hung on that mount, and it's older than mine by the symmetrical pier cap. I'll go with the options offered by the offset, but I admire the earlier stuff.
You have a clamping knob in the DEC housing? I don't even have a hole for that. Is the housing clamp needed due to the DEC slo mo assembly you have? nnnnnno that assembly (I'm drooling) should lock the shaft.
Are your clamp knobs original? My clamp knobs, with the captive slide rod, are original and the slide rod is stuck with the setting circle against the stop collar. …….
OK, sheesh I need to read my own post.
Robert, look at your picture in post #15 as well as the one in post #16. The DEC pointer is very long, and I now remember seeing this before. This puts the original setting circle down far enough to clear the slide rod on the clamp. Also look at that original setting circle with the rubber grommet. I have that grommet installed on my RA circle for safe keeping. My current circles are original Edmund prints but not bored for this particular mount. I knew that because the RA circle is too small to go on the housing. I'm taking a NOW pic of this. This is awesome. I will be modifying the original configuration such that it could still be made original if desired, but I doubt any one would want to.
Here are my current Edmund setting circles. I acquired these because the original ones on the mount were pretty bad. My DEC circle (top) is a slide fit on the shaft as it and will stay that way. I'll clamp it between two stops with a rubber ring on each side which should hold it solid once set, yet allow easy enough reset.
The RA circle has the right size hole to hold the original dec circle grommet. I'll keep that grommet in the original parts pack. The RA circle needs to be bored to fit on the RA housing shoulder. The only thing I don't know is what Edmund put on each side of the RA circle if anything. Not a huge deal now bit it would be nice to know. I'll cut some oversized OD rubber washers and back that with some metal ones. My rubber strips for making the 6" mount washers are wide enough to make the 8" mount washers. This will work.
Edited by apfever, 07 November 2018 - 10:55 PM.
Posted 07 November 2018 - 11:46 PM
That gadget on the dec shaft is a optional slo-motion unit.
It and the other knob on the dec housing are handy for locking the mount up when
installing or removing the OTA.
My drive is Pacific Instruments and the setting circle is part of the worm gear.
Posted 07 November 2018 - 11:55 PM
Here's something really neat, these circles were optional and go on the machined spots on
the Edmund Extra Heavy Duty, rarer than a albino possum.
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Posted 30 November 2018 - 10:49 PM
Posted 01 December 2018 - 04:18 AM
I gave away my original setting circles that were not in very good condition, after I obtained the Edmund circles in post #60 above. The replacements I have are an original Edmund issue, not a remake. The DEC circle has a slide fit 1.5" hole where the original circle was slightly larger to accommodate the bushing. The RA circle has the slightly oversized hole so I used it to show the DEC bushing in place.
I need to bore out my RA circle to fit on the RA housing, and also make original flat type rubber bushings for it.
I'll leave the DEC circle a slip fit and just keep the original bushing (it's the actual original factory bushing) in the original parts bag.
I decided I want to keep the circles installed but they are a delicate item so they'll get a backup. The mod will be completely reversible but doubtful anyone would. Both circles get backed up by an aluminum plate 6" in diameter. The circles are 5-7/8" diameter so the plate will protect out to the edge. The DEC circle gets the washer shown installed on the top. The washer is for a 1-3/8" bolt and has a perfect slip fit 1.5" hole. The washer goes right to the edge of the print and doesn't cover any. The RA circle is much more protected in it's nest and it doesn't swing around like the DEC does. I may or may not do a protective top plate for the RA circle. The DEC circle assembly will be held in place by two clamp collars. I'm using all split stop collars now so no more set screw damnage. I have an order for 10 of those collars in 1.5" size and I'll be using them on other mounts. I have several 1.5" mounts.
I have been busy with this, just haven't posted till I get some aspect finished. I'm hitting a block now on what to refurbish on the clock motor assemblies. Maybe a whole new string on this series of Edmund drives.
Edited by apfever, 01 December 2018 - 04:19 AM.
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Posted 01 December 2018 - 05:42 AM
I'm down to the drives. I went bananas on these. This series of drives is the most consistently rusted up mess that I've seen in drives. I have one more body assembly in the basement that is so frozen up on the shaft that I can't get it off. Clearance won't let me use the press. I may have to pull the saddle off the RA shaft since the motor assembly has the shaft locked in the RA housing. Once off (one way or the other) I'll soak it in Evaporust and lube, then press the motor drive housing off the motor shaft. My press will either get it off intact or crack something which wouldn't be a loss at that stage, it has to come off the RA shaft for me to rebuild that mount.
Tons of stainless. I took these down to every nut and bolt including the 4-48 X 1/8" set screws for the worms which I found in stainless. I ordered 200 of those set screws since I found them on clearance for 2 cents each - tough to find.
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Posted 01 December 2018 - 05:50 AM
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Posted 08 December 2018 - 10:44 PM
stainless order arrived yesterday so I put these together. I'll do a separate string on these drives since they cover a variety of Edmund mounts.
The three up front are done and for use on the Edmund 4.25", 6", and 8" all on grey pier GEM. The two in back with gears are dry assemblies that will be stored, thus the top Nyloc is not set. The parts unit in the upper left is just that - parts so far. I only have the 4 original motors shown so one geared set will get stored without.
Edited by apfever, 08 December 2018 - 10:52 PM.
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Posted 08 December 2018 - 11:04 PM
I didn't think this was going to work, maybe I got lucky. The 6 sets of basic assemblies in the previous post are due to me getting this frozen unit apart. I removed the RA housing and shaft assembly from the mount, and put the whole thing in the press. This took several tons of pressure at the least, it became very scary tight. The first 'pop' jolted the whole press and sent stuff flying but I saw that coming.
The shaft housing needs to be supported as shown and as close to the center section as possible. DON'T support the housing by the bolted aluminum pins on the right. I would have sheared those off guaranteed. I used the allen wrench and shim to get back under the black part of the housing. Once everything was cleaned up, this unit worked like a charm, smooth.
Notice the rust on the gear shaft coming out the bottom of the housing. I had this soaked for days in penetrating lube, PB Blaster. I'm out of Kroil.
Edited by apfever, 08 December 2018 - 11:08 PM.
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Posted 08 December 2018 - 11:26 PM
None of this is a spit shine. I prefer to keep patina and minimize polishing. There was no pressure action using the 'Bar Keepers Friend' cleanser which is an abrasive cleaner. I was going for the chemical action only due to the oxalic acid in the cleanser. These results are just from finger tip movement of the slurry around the gears. I did use a toothbrush to lightly work the cleaner in the gear teeth. The label list brass and aluminum as appropriate items. Any scratches or swirls (center gear) were on the gears to begin with. I finger tipped the slurry around the gears, following the grain of the machining. They all started about the same as the top gear for comparison which includes green oxide at the leather clutch contact area.
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Posted 02 January 2019 - 02:15 PM
This is quick due to the concurrent Star-Liner string. It was either take the one big one through the house and into the basement or move two complete GEM up the stairs and out. Here's the group upstairs and out. Counter weights and such all off for quick time. I need to clear and blanket a spot for the peripherals. This ongoing goal has been a forever group thing. The truck just went out for a few days above freezing and I need to put a sled in here, so quick pic before filling the garage again. I'll finish these scopes here, hopefully get a lot done while keeping some heat in here for the sled.
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Posted 02 January 2019 - 02:23 PM
These full go clock drives, to the n'th degree, stainless anything I could find which is pretty much all the hardware and then some, minor reverse engineering but always some. I'll put the full entourage on or up here during the next few days.
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