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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: BarabinoSr]
      #6223083 - 11/29/13 10:06 AM

Hi All,
This is where I get my materials for building mounts.
Bearings:
http://www.ebay.com/sch/i.html?_odkw=telescope+mirror&_osacat=0&_from...

Aluminum plate:
https://www.yarde.com/cgi-bin/dropshop.pl?alloy=6061-T651++&form=PL

Stainless Shafting:
https://www.yarde.com/catalog/drop3rdbr.html

Other good sources for metals:
http://www.onlinemetals.com/
http://www.speedymetals.com/default.aspx

Regards Norm


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6225376 - 11/30/13 03:05 PM

I've got a 2" tap base pillow block with the bearing set not quite true. Looks like it's not quite seated all the way into the pillow block.

Can I just gently bang on the high side of the outer race with a piece of hardwood and deadblow mallet, and try to seat it better?


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Chuck Hards]
      #6225805 - 11/30/13 07:42 PM

Chuck,
Yes you should be able to. Most pillow blocks are self-aligning. Usually there is slight spherical surface to
the outside of the bearing and inside of the cast iron base.
put a little light oil between the two surfaces and tap it
straight.
Norm


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Chuck Hards]
      #6225810 - 11/30/13 07:44 PM

My 1" pillow block bearings came today. I set them next to the 2" and was surprised. A 2" shaft mount is not twice the size of a 1" shaft mount.

It's 4X the size and mass!

I'll get the 1-1/2" bearings in December when I pick up some aluminum plate. Still trying to make up my mind on shaft particulars. Leaning toward SS.


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Chuck Hards]
      #6225839 - 11/30/13 08:04 PM

One thing about using stainless is you don't have to be concerned about rust. If you need to take the thing apart
someday you can slide the bearings off the shaft much easier
if they are not all rusted. On stainless steel you must be
aware that some types will rust some and will also draw a
magnet. Generally, with out looking it up,the 300 series
won't rust but 400 series some will. I like 303 because it
is easier to machine. 304 is some what tougher to machine
especially on my old lathes using HS steel tool bits.
Also be aware unless you use ground or bearing shaft stock
it will be a little oversize and you won't be able to slip the bearings on. I put the shaft in the lathe and use emery
cloth to remove some stock so they'll fit.
Regards Norm


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obin robinson
Carpal Tunnel
*****

Reged: 10/25/12

Loc: League City, TX
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6225871 - 11/30/13 08:29 PM

Thanks for the info! This definitely looks like something worth building. My only worry is when I get a chance to start the project all the Byers drives will be gone! Is there anyone else making drives of that same quality level?

obin


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: obin robinson]
      #6225893 - 11/30/13 08:47 PM

Yes there is another:
http://www.aeroquest-machining.com/

Regards Norm


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6225898 - 11/30/13 08:49 PM

And another:
http://www.opticcraft.com/


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bremms
Carpal Tunnel
*****

Reged: 08/31/12

Loc: SC
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6226045 - 11/30/13 10:23 PM

Norm is correct about plain stock. I sanded mine down on a lathe. 1" Mount to a 2" mount... 8x the mass on average. double each dimension. There is a turnover point where the mass just gets out of control. That's about at a 2" mount.
My 1.5 " head weighs about 65lbs without counterweight. My 1" head weighs about 20 lbs.


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obin robinson
Carpal Tunnel
*****

Reged: 10/25/12

Loc: League City, TX
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: bremms]
      #6226104 - 11/30/13 10:50 PM

Quote:

Norm is correct about plain stock. I sanded mine down on a lathe. 1" Mount to a 2" mount... 8x the mass on average. double each dimension. There is a turnover point where the mass just gets out of control. That's about at a 2" mount.
My 1.5 " head weighs about 65lbs without counterweight. My 1" head weighs about 20 lbs.




What is the max weight a 1.5" head can hold? Could you put a 50lb OTA on it safely?

obin


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: bremms]
      #6226183 - 11/30/13 11:46 PM

Quote:

1" Mount to a 2" mount... 8x the mass on average. double each dimension. There is a turnover point where the mass just gets out of control. That's about at a 2" mount.
My 1.5 " head weighs about 65lbs without counterweight. My 1" head weighs about 20 lbs.




I believe you on the mass multiplier factor. I'm using the 2" bearings for an equatorial fork mount. Pretty standard polar axis but the fork will probably be composite construction, with small stub shafts for DEC, and possibly only 1" dia.
I think 1-1/2" shafts is the biggest I'll go with one of these GEMs unless I build that observatory one day.


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6226244 - 12/01/13 12:56 AM

Quote:

Gary you are correct. If I were substituting Hollow for
solid I would use at least a 1/4" wall thickness.For most
of our uses that probably would be adequate.




I was thinking of possibly going with thick-walled tubing for the RA shaft, which would allow using an aligned GLP to aid in polar alignment. You'd have to drill a small hole in the DEC shaft to allow the beam to pass through, though.


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bremms
Carpal Tunnel
*****

Reged: 08/31/12

Loc: SC
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Chuck Hards]
      #6226248 - 12/01/13 01:02 AM

Well built a 1.5 shaft mount should hold a 50 lb scope. Not a large refractor. Should be good for a 6" f12 not much larger

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mikey cee
Postmaster
*****

Reged: 01/18/07

Loc: bellevue ne.
Re: 1.5" Tap Base Pillow Block Mount Coming Together [Re: bremms]
      #6226330 - 12/01/13 02:36 AM Attachment (26 downloads)

I learned way back in 1978 that a pillow block mounting was what I had to have and not cut any corners. It is just a dinky 3" set up. Worked great for my 8" F/13.3 which I just recetly converted into a 10" F/11!! Those bearings cost me $90 apiece....probably a fortune in today's dollars! Mike

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bremms
Carpal Tunnel
*****

Reged: 08/31/12

Loc: SC
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: mikey cee]
      #6226500 - 12/01/13 08:10 AM

I like the RA plate welded to the pier. Great for an observatory installation. The simple construction of these mounts is great. I picked up my bearings (Browning) for about $15 each NOS. about $75 for Alu plate and bushings. If I was going to an observatory installation I would use steel.
Nice mount for a big frac.


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: bremms]
      #6228579 - 12/02/13 08:39 AM

Obin,
Here is a chart that I use as a guide for load
capacities. These are made with steel plate so I'm not
sure what the difference would be using AL plate.

http://www.opticcraft.com/telescopemounts.html

Regards Norm


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: bremms]
      #6228584 - 12/02/13 08:42 AM

I like the sub-diameter counterweight shaft. It could be threaded-in for a portable mount. Interesting color choice, too.
I'm trying to figure out the DEC tangent-arm mechanism. Looks to be spring-loaded (to eliminate backlash?) and I think I see a right-angle gear setup to put the adjustment knob at the eyepiece, yes? Or is it motorized?


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delta
newbie


Reged: 07/12/13

Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Chuck Hards]
      #6231320 - 12/03/13 12:21 PM

I am a newbie here, but have some DIY experience and am considering building my GEM in a course of a year or two.
The goal is to build it for astrophotography. Therefore the precision required.

My question is how would you compare pillow blocks vs separate bearings housing in this context?

I am studying this http://www.astronomiainumbria.org/advanced_internet_files/meccanica/easyweb.e... for some time already and it looks very interesting and convincing.

Alex


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Norm Meyer
sage
*****

Reged: 02/08/09

Loc: Warren, ME 04864
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: delta]
      #6231497 - 12/03/13 01:50 PM


Alex,
I looked at the website and poured over the plans. If
you're a halfway decent machinist and have your own machine
tools you can do it. It will take a lot of time and the
cost will not be really low. My machines are old my lathes
are pretty good but my horizontal mill leaves something to be desired. I've built several mounts and I find the pillow
block mounts are fairly easy,and not too expensive to make.
As far as precision they would match the one shown. You
could make it as beefy as you like to support the weight you
want to. If you have an observatory you could make it out of steel. If you want it portable use aluminum. I made one
with 1/2" steel plate and 1" pillow blocks and it was very
rigid. The more mass you have the more rigid but that means
it will be heavy.

IMHO
Regards Norm


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Chuck Hards
Post Laureate
*****

Reged: 05/03/10

Loc: The Great Basin
Re: 1.5" Tap Base Pillow Block Mount Coming Together new [Re: Norm Meyer]
      #6231663 - 12/03/13 03:21 PM

I agree with Norm, a pillow-block mount is as solid and precise as anyone would ever need. You can even use double bearings if desired, though that would be overkill for the light loads of a telescope, in most cases. I've seen some observatory-class pillow block mounts made over the years. For imaging you will need precise drives on each axis, and a large gear diameter on the RA axis is a plus. The larger the gear, generally, the smoother the drive. You'll throw-away fewer subs.

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