- Joined
- Jan 2, 2016
- Messages
- 1,953
I had a feeling you were going the two bearing route. Do you have a plan to keep dust out of the bearings?
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The Giant Binocular
- Thread starter savarin
- Start date
- Joined
- May 16, 2016
- Messages
- 1,704
Looking good Charles, yes the two bearing set up is the way to go here, keep it nice and tight, don't want that scope wobbling. I think you do need some kind of dust protection as well.
- Joined
- Aug 22, 2012
- Messages
- 4,271
Thanks Bob.
At the moment I'm turning a centre that will fit the inside of the bearing and be welded to the top plate.
Then I can hold it all in the chuck, centre it, and turn the plate circular.
Then I can flip it as it will now fit in the four jaw (just) and I can cut an inset from the edge to take another tube that will slide over the main pier assembly and turn the welded boss down to fit the inner bearing race.
I'm hoping a local stainless sheet metal company can roll and weld one to size,
Then I will glue a felt band to the top edge of the pier as a dust seal. (phew, still to much left to do.)
At the moment I'm turning a centre that will fit the inside of the bearing and be welded to the top plate.
Then I can hold it all in the chuck, centre it, and turn the plate circular.
Then I can flip it as it will now fit in the four jaw (just) and I can cut an inset from the edge to take another tube that will slide over the main pier assembly and turn the welded boss down to fit the inner bearing race.
I'm hoping a local stainless sheet metal company can roll and weld one to size,
Then I will glue a felt band to the top edge of the pier as a dust seal. (phew, still to much left to do.)
- Joined
- Aug 22, 2012
- Messages
- 4,271
The plate was just too large to fit in my 4 jaw so I drilled and tapped 4 holes to bolt it to the face plate for facing off.
I welded a boss in the centre to fit into the 90mm taper roller. Unfortunately I miscalculated the depth of the weld and had to turn virtually all of it off.
So I thought if I cut the centre of the boss away leaving a collar I could then weld it inside.
I used a hole saw for speed and ease.
What may be an interesting fact....... the saw I used first, a Starret, squealed worse than a struck pig, the second one was a Sutton tools, that cut through almost like a hot knife through butter.
Todays job (if I'm allowed the time is to weld the spreader bars and turn up the shaft that holds it all together.
I welded a boss in the centre to fit into the 90mm taper roller. Unfortunately I miscalculated the depth of the weld and had to turn virtually all of it off.
So I thought if I cut the centre of the boss away leaving a collar I could then weld it inside.
I used a hole saw for speed and ease.
What may be an interesting fact....... the saw I used first, a Starret, squealed worse than a struck pig, the second one was a Sutton tools, that cut through almost like a hot knife through butter.
Todays job (if I'm allowed the time is to weld the spreader bars and turn up the shaft that holds it all together.
- Joined
- Aug 22, 2012
- Messages
- 4,271
The spreader bars are in
As I had a length of M12 allthread I decided to use that to hold everything together rather than turn up another shaft and thread it, yeah, lazy, thats me.
Now comes a difficult decision. The altitude bearings
My first thought was casting the blocks in brass because as baron also thought alloy might gall but fear of the weight of a crucible of molten brass to do just one is holding me back for the time being although I really fancy using the brass.
The next thought was casting in alloy, definitely easier but the galling thought is still there.
Then I thought maybe a split sheath of hard brass around the altitude shaft and clamped in the alloy bearing blocks, this would compress onto the shaft producing sufficient friction to remove all the play and become a non galling bearing.
The third thought is to use hardwood blocks as the bearings as the ones I used on my fixed steady work very well but I'm not so sure how strong the method of holding them to the azimuth plate would be.
Any ideas people? Please chime in and help me come to a decision.
As I had a length of M12 allthread I decided to use that to hold everything together rather than turn up another shaft and thread it, yeah, lazy, thats me.
Now comes a difficult decision. The altitude bearings
My first thought was casting the blocks in brass because as baron also thought alloy might gall but fear of the weight of a crucible of molten brass to do just one is holding me back for the time being although I really fancy using the brass.
The next thought was casting in alloy, definitely easier but the galling thought is still there.
Then I thought maybe a split sheath of hard brass around the altitude shaft and clamped in the alloy bearing blocks, this would compress onto the shaft producing sufficient friction to remove all the play and become a non galling bearing.
The third thought is to use hardwood blocks as the bearings as the ones I used on my fixed steady work very well but I'm not so sure how strong the method of holding them to the azimuth plate would be.
Any ideas people? Please chime in and help me come to a decision.
- Joined
- Feb 17, 2013
- Messages
- 4,417
Maybe a bit primitive, but ...
You could use plastic liners, cut out of plastic bottles, inside whatever material you want to use for the blocks. Here in the US, laundry bleach comes in white plastic bottles (not sure of the identity of the plastic, possibly a high density polyethylene) that are pretty uniform in thickness (maybe .020" to .032"). I've used this plastic as a bearing liner in the past, and it has held up well.
You could use plastic liners, cut out of plastic bottles, inside whatever material you want to use for the blocks. Here in the US, laundry bleach comes in white plastic bottles (not sure of the identity of the plastic, possibly a high density polyethylene) that are pretty uniform in thickness (maybe .020" to .032"). I've used this plastic as a bearing liner in the past, and it has held up well.
- Joined
- Aug 22, 2012
- Messages
- 4,271
The bino build came to a halt whilst I cleaned and tidied up the workshop, something that was long overdue.
In the course of tidying up I found my mirror tester covered in rat crap so took a short break to re furbish it even though I am no where near requiring it for testing as I havnt started grinding the mirrors yet but I just couldnt leave it in that appalling state.
The micrometers had to be stripped and cleaned so I painted the base and added better slide supports and a fourth adjustable foot so it would sit in a stable position no matter what the surface.
The long white rectangle is a glass microscope slide for the next stage to slide upon.
This is the second stage for the "X" direction and sits on the base like so. 2 "V" blocks slide on the stainless rail with the adjusting screw just to the left of the micrometer slides in the glass slide. Those little knurled thumb screws are the ones that filled my thumb with invisible splinters of stainless steel. https://www.hobby-machinist.com/thr...earnt-something-new-lesson.76300/#post-639821
The "Y" and "Z" are a single unit on the third stage
and sits on the second stage.
Both the second and third stage have lead blocks bolted to them as vibration dampers.
The sliding head is held with 2 nylon screws for friction and are locked when everything is in alignment.
The wheel contains 6 diodes, red, green, blue, white, yellow and orange. No real reason as most testing will be done in green but I wanted to see if there was any difference in the readings with different colours,
The diodes are are switched on when they are directly below the peep hole.
The rheostat controls the brightness of the diode.
I still have to attach the magnet that holds the screens or razor blade in place over the diodes as the rat crap ruined them.
Now I need some dry days to do a bit of casting and continue with the real job.
In the course of tidying up I found my mirror tester covered in rat crap so took a short break to re furbish it even though I am no where near requiring it for testing as I havnt started grinding the mirrors yet but I just couldnt leave it in that appalling state.
The micrometers had to be stripped and cleaned so I painted the base and added better slide supports and a fourth adjustable foot so it would sit in a stable position no matter what the surface.
The long white rectangle is a glass microscope slide for the next stage to slide upon.
This is the second stage for the "X" direction and sits on the base like so. 2 "V" blocks slide on the stainless rail with the adjusting screw just to the left of the micrometer slides in the glass slide. Those little knurled thumb screws are the ones that filled my thumb with invisible splinters of stainless steel. https://www.hobby-machinist.com/thr...earnt-something-new-lesson.76300/#post-639821
The "Y" and "Z" are a single unit on the third stage
and sits on the second stage.
Both the second and third stage have lead blocks bolted to them as vibration dampers.
The sliding head is held with 2 nylon screws for friction and are locked when everything is in alignment.
The wheel contains 6 diodes, red, green, blue, white, yellow and orange. No real reason as most testing will be done in green but I wanted to see if there was any difference in the readings with different colours,
The diodes are are switched on when they are directly below the peep hole.
The rheostat controls the brightness of the diode.
I still have to attach the magnet that holds the screens or razor blade in place over the diodes as the rat crap ruined them.
Now I need some dry days to do a bit of casting and continue with the real job.
