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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Another Berry-style Refractor Mount
      #4541844 - 04/24/11 08:34 PM Attachment (335 downloads)

I just finished my second Richard Berry refractor mount and thought I would share a few photos and lessons learned along the way. Two of the hardest parts of fabrication are building the central hub, and drilling the holes for the tripod leg bolts.

The hub is built up by cutting individual pieces from plywood and laminating them together. The issue is consistency in measuring the 120 spacing, and getting accurate cuts. It seems inevitable to have considerable overlap as the layers are glued together, leading to lots of sanding. To solve this problem, I glued the central hub together first, then cut a polygon on the table saw. Very slick. Unfortunately, I either made a measurement error or my original table saw mitre guide failed to cut the proper angle (I have since bought a new mitre guide). So, the legs are not precisely spaced at 120 degree intervals, but at least little sanding was required.

The second issue in fabricating the Berry design it drilling straight and accurate deep holes in the hub for the tripod leg bolts. To solve this issue I used two matched blocks of wood to make each lobe. These were drilled with a forstner bit then glued to the polygonal hub body. I used a biscuit joint for strength, and after the top of the hub was attached I added an additional dowel pin. I found this variation to be extremely successful.

For added rigidity, I upsized all of the hardware from 5/16 to 1/2 bolts, all in bronze sleeve bearings to eliminate wear on the wood. I hardly every use 1/4 in my projects anymore.


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541855 - 04/24/11 08:38 PM Attachment (207 downloads)

The sleeve bearing for azimuth pin. Another advantage of 1/2 hardware is I can attach my Losmandy GM-8 equatorial head to the tripod with a MA adapter. The Walnut plugs cover dowel pins used to reinforce the leg mount blocks.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541865 - 04/24/11 08:44 PM Attachment (187 downloads)

On a tip from a CN member who wished to remain anonymous, I used Black Walnut for the legs. This person claimed in quantitive tests this species bested 30 other common hardwood species in damping. I just liked the looks.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541867 - 04/24/11 08:45 PM Attachment (169 downloads)

This is a spare set of altitude bearings that can attach directly to the Astro-Physics rings that came with my scope. The fit is very tight, and they angle somewhat depending upon how tightly the rings are closed. Seemed like a good idea at the time, but these will sit in the closet in the event I every lose the primary ring set.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541869 - 04/24/11 08:45 PM Attachment (143 downloads)

And this would be the primary ring set.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541872 - 04/24/11 08:46 PM Attachment (185 downloads)

And the finished product. I want to build a backgammon table, so I decided to practice some simple wood insets using PurpleHeart, Mahogany, and Black Walnut. Kind of busy looking, but I was having fun.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541879 - 04/24/11 08:50 PM Attachment (141 downloads)

End view. Ill probably use the remaining PurpleHeart to make a Telrad platform that attaches using Neodymium magnets. Those little suckers are strong!

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541890 - 04/24/11 08:56 PM Attachment (147 downloads)

Front view of the mount. Last Thursday was the shakedown, and I am pleased with the overall rigidity and performance. Tracking was rather easy at 339x. However, the mount is balance sensitive. I can balance to use my heavy widefields, or my lighter Brandons. Using both in the same session is a bit problematic now. Ill have to work on that a bit.

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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541897 - 04/24/11 09:00 PM Attachment (158 downloads)

And lastly, a Minimalist Glass Lover's dream. APO doublet, dialectric diagonal, and 48 Brandon. I actually bought the scope because it had about the optimum focal ratio to maximum this eyepiece for my eye.

Dark nebula can run, but they can't hide.


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Don W
demi-god
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Reged: 05/19/03

Loc: Wisconsin, USA
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4541919 - 04/24/11 09:09 PM

Beautiful job and one of my favorite scopes that I wish I'd never sold.

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avarakin
Carpal Tunnel
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Reged: 07/13/09

Loc: Parsippany NJ, USA
Re: Another Berry-style Refractor Mount new [Re: Don W]
      #4541969 - 04/24/11 09:28 PM

This scope is really lucky to be mounted on such a beautiful mount!

Alex


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StarStuff1
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Reged: 04/01/07

Loc: South of the Mason-Dixon Line
Re: Another Berry-style Refractor Mount new [Re: Don W]
      #4541970 - 04/24/11 09:28 PM

Nice work! Beautiful form and great function.

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plyscope
Pooh-Bah


Reged: 11/23/06

Loc: Perth, West Australia
Re: Another Berry-style Refractor Mount new [Re: StarStuff1]
      #4542019 - 04/24/11 09:56 PM

That is a really nice mount Jeff. Thanks for the great pictures. I am planning another Berry mount for a 5" achromat. This thread is great inspiration.

Andy


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Mr Magoo
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Reged: 11/05/05

Loc: Franklin, Indiana
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4542039 - 04/24/11 10:05 PM

Very nice work Jeff. A question, how do you determine the length of the counterweight tray?

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Tom Andrews
Pooh-Bah
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Reged: 01/25/07

Loc: Albuquerque, NM
Re: Another Berry-style Refractor Mount new [Re: Mr Magoo]
      #4542136 - 04/24/11 10:51 PM

Truly awesome build! Gorgeous.

Makes me want to buy a refractor just to have an excuse to build one of those!


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Brian Reed

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Reged: 10/29/04

Loc: North East Illinois
Re: Another Berry-style Refractor Mount new [Re: Tom Andrews]
      #4542161 - 04/24/11 11:04 PM

The inlay is stunning. Awesome Job!!!

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Jeff Morgan
Postmaster
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Mr Magoo]
      #4542510 - 04/25/11 05:23 AM Attachment (108 downloads)

Quote:

Very nice work Jeff. A question, how do you determine the length of the counterweight tray?




Thanks guys!

As to the length of the cradle, there really is no set dimension. It's function is to hold the tube on one end, and counterweight on the other. So if you make it long you can get by with a smaller weight, but it is more cumbersome to transport. Make it short, and you need a heavier weight. There are a couple of other options:

1) Eliminate it completely and do the "Weightless Woodshop Refractor" style that Chuck Hard had published in S&T. Basically, the overhang is replaced by a teflon tipped hook that catches under the hub. I built my first one like this, it works well (photo attached). Come to think of it, I can't recall why I did not do this one that way.

2) Truncate the extension and mount a horizontal counterweight shaft. My Star12 only weighs 11 pounds (call it 13 operational weight) so a steel shaft by itself would almost be enough.


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Mr Magoo
Carpal Tunnel
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Reged: 11/05/05

Loc: Franklin, Indiana
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4542521 - 04/25/11 05:33 AM

Thanks Jeff. I really like the hook idea. I had not seen that article.

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Bob Myler
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Reged: 05/18/06

Loc: St Louis, MO
Re: Another Berry-style Refractor Mount new [Re: Mr Magoo]
      #4544004 - 04/25/11 08:45 PM

Simply stunning work. I understand that accurately drilling 5-1/2" straight through each leg hub is an iffy proposition at best - especially since you can't vertically square Berry's trefoil hub on a drill press. Somewhat akin to drilling thru a mountain and hoping you arrive at the right place on the other side.

Jeff, your solution is elegant and makes much more sense.


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plyscope
Pooh-Bah


Reged: 11/23/06

Loc: Perth, West Australia
Re: Another Berry-style Refractor Mount new [Re: Bob Myler]
      #4544188 - 04/25/11 10:07 PM

Some more apo's on Berry mounts but I like yours better Jeff!
AP and TMB on Berry

Andy


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rboeAdministrator

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Reged: 03/16/02

Loc: Phx, AZ
Re: Another Berry-style Refractor Mount new [Re: plyscope]
      #4544274 - 04/25/11 10:52 PM

You are getting some woodworking skills.

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Jeff Morgan
Postmaster
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Don W]
      #4544427 - 04/26/11 12:10 AM

Quote:

Beautiful job and one of my favorite scopes that I wish I'd never sold.




Oh, I think we all have a scope we wish we never sold.

That was first light for the Star12 (for this owner). First impression was stunning. Only looked at a three targets in a short session of 2/5 seeing, but the Star12 still handled Gamma Virginis with contemptuous ease. Wow.

I can see why people wait years for AP scopes.


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Jeff Morgan
Postmaster
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Bob Myler]
      #4544437 - 04/26/11 12:16 AM

Quote:

Simply stunning work. I understand that accurately drilling 5-1/2" straight through each leg hub is an iffy proposition at best - especially since you can't vertically square Berry's trefoil hub on a drill press.





Exactly the problem. And even if you could square it on the drill press the length on a forstner bit is inadequate for a solid block. I was afraid a spade bit would not cut a precise hole, leading to a source of wobble in the mount.


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Mr Magoo]
      #4544441 - 04/26/11 12:18 AM

Quote:

Thanks Jeff. I really like the hook idea. I had not seen that article.




I don't have a reference immediately available for you, but the author is on CloudyNights from time to time. You could probably pm him for more details. It's a clever idea.


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Wes James
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Reged: 04/12/06

Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4544670 - 04/26/11 05:13 AM

Not much I can add to other's comments.... other than to agree- beautiful, exquisite craftsmanship and execution, Jeff-
What kind of plywood did you use in the hub of the tripod? Looks like Maple piano pinblock material!


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Wes James]
      #4545102 - 04/26/11 10:19 AM

Quote:


What kind of plywood did you use in the hub of the tripod? Looks like Maple piano pinblock material!




Nope, standard baltic birch on the plywood sections. I sand it down to 400 grit, then it takes on that look during finishing. I'm using Sam Maloof Oil/Polyurethane (four coats) followed by Sam Maloof Oil/Wax (two coats). Buff it with cloth or 0000 steel wool between each coat.

Despite the sound of it, It is very easy to apply (wipe on wipe off) and holds up well. The product is intended for furniture (that is to say, indoor use). I'm not sure how it would hold up in a high moisture climate. I guess worst case is you go back in a year or two and refinish with spar varnish, but in my dry climate I have pieces holding up well after five years.

I have actually been very frustrated with baltic birch. Maybe it is the dry climate here, but I continue to get lots of tear-out, even with new sharp tools. This project has lots of them, they just don't show at that camera angle and distance. I would like to find a replacement wood for future projects. I can get mahogany plywood, but the veneer is thin, and any telescope subject to frequent transport inevitably gets scratched. Also, the cores on that are MDF (yuck!). I guess I could rip strips of hardwood and glue them to the exposed edges.

If I didn't mention it, the other woods are Black Walnut, Mahogany, and PurpleHeart. The first two are rather easy to work (although the walnut will dull tools faster). On the walnut I initially made the tripod side pieces too thick (13/16" what was I thinking?!) After releasing the clamps the wood had enough spring to actually break the glue bonds! So, I thinned them from to 5/8" on the table saw. And while I hate to use metal connectors, drywall screws supplemented the glue on the second attempt. (The same technique was used on my first tripod.) To hide the screw heads a 5/8" forstner bit was used to make a recess, with further counter sink on the screw heads. Then I glued 5/8" walnut plugs over the "wound". The grain on this wood can be vivid, so it was hard to match plugs perfectly. Close inspection will reveal them. But the wood darkened substantially during the oiling process so that helps then plugs "blend in". And speaking of darkening, the only stain used was red mahogany used (naturally) on the mahogany accents. But even here I did not give the stain much dwell time, most of the darkening comes from the oiling.

The PurpleHeart tends to be brittle and splinter when you are cutting it into thin strips or sections. It also eats up lots of sandpaper, but it does look nice as it oxidizes. I let it sit for about three weeks before I applied finish to deepen the color.


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dan_h
Carpal Tunnel


Reged: 12/10/07

Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4545274 - 04/26/11 11:26 AM

Quote:

I have actually been very frustrated with baltic birch. Maybe it is the dry climate here, but I continue to get lots of tear-out, even with new sharp tools.





That's becoming my experience. Any cuts across the grain are pretty messy. I do my best to keep the good side up whenever I'm working with this on the table saw. I can't always hide a sloppy edge inside the project.

I don't think it has to do with the dry climate. we're pretty wet around here right now.

Your mount is beautiful. Nice job!

dan


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Bob Myler]
      #4618260 - 06/03/11 11:30 AM Attachment (47 downloads)

After a month of use I have found another design improvement for Berry-style mounts. The original design calls for a azimuth bolt secured by a nut. The orientation of the bolt is head up, threads down. The problem with this is that the nut is inaccessible once you thread the center pipe in place. Sure, you can unhook the leg spreaders and unthread the center pipe to access the nut, but this proves rather inconvenient. But why would one want to do this in the first place?

1) To adjust azimuth friction.
2) To remove the scope cradle for a lighter carry load, or packing in the car.

So, the easy solution was to invert the bolt. I did this by enlarging the hole on the bottom side of the hub, and burying the bolt in 2-ton epoxy. The threaded end now protrudes from the top, allowing for easy access for adjusting azimuth friction.


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Jeff Morgan
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Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4618268 - 06/03/11 11:33 AM Attachment (53 downloads)

The modification also makes it easier to go from azimuth to equatorial mode. I can swap mount heads in less than 3 minutes.

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seryddwr
Innocent Bystander
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Reged: 02/19/10

Loc: La-la land.
Re: Another Berry-style Refractor Mount new [Re: Jeff Morgan]
      #4618586 - 06/03/11 02:29 PM

As Wile E. would say: "Gad, I'm such a genius!"

Nice work, Jeff.


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Frank Dement
member


Reged: 05/02/05

Loc: Eastern Washington state
Re: Another Berry-style Refractor Mount new [Re: seryddwr]
      #4618752 - 06/03/11 03:58 PM Attachment (53 downloads)

My rendition is crude by comparison. Built mine back in the ninetys. Also with a blue pipe.
You did a really beautiful job. If I can find a pic of my ancient effort I will attach it to this note.


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Frank Dement
member


Reged: 05/02/05

Loc: Eastern Washington state
Re: Another Berry-style Refractor Mount *DELETED* new [Re: Frank Dement]
      #4618938 - 06/03/11 05:26 PM

Post deleted by Frank Dement

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Mike I. Jones
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Reged: 07/02/06

Loc: Fort Worth TX
Re: Another Berry-style Refractor Mount new [Re: Frank Dement]
      #4619053 - 06/03/11 06:21 PM

Frank,
Just edit your post, and change pictures by using the same Browse button you used before. Should change the picture when you hit Save and come back to the forum. Let me know if you need help.
Mike


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Don Allen
scholastic sledgehammer


Reged: 07/07/05

Loc: Charleston, SC
Re: Another Berry-style Refractor Mount new [Re: Mike I. Jones]
      #4619170 - 06/03/11 07:44 PM

Sweet.

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Jeff Morgan
Postmaster
*****

Reged: 09/28/03

Loc: Prescott, AZ
Re: Another Berry-style Refractor Mount new [Re: Frank Dement]
      #4622165 - 06/05/11 12:22 PM

Quote:

My rendition is crude by comparison. Built mine back in the ninetys. Also with a blue pipe.
You did a really beautiful job. If I can find a pic of my ancient effort I will attach it to this note.




That looks like a great mount, the main difference is just the rounding on cradle. I like the lightening holes on the leg, I never thought of this. Light weight was never a criteria of the Berry design the lightening cuts are a great idea.


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