Space99
sage
Reged: 08/14/08
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ATM eq mount/Byers worm gear
#5350637 - 08/03/12 06:13 PM
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Hi everyone,
long time no post and I like to seek the wisdom of you all 
I have 2 good quality worm gear. For the RA have a 11" 359:1 Byers with spring-loaded worm carriage. The DEC is a 7" with clutch plate.
The Byers has the usual clutch/pressure-plate arrangement.
I like to build a good EQ mount. Many commercial example I studied for the worm location. Old Byers mount has the worm wheel mid located between the north-south RA bearings. Astro-Physics has the worm on the front of the bearings, and I assume trust-bearing loaded. The drum-like clutch is accessable from outside of the RA drum. The original Byers worm wheel have to be exposed to make it adjustable/balance to make it work.
Older mount has the worm located in the "south" of both bearings, make it accessable the clutch set-screws.
I plan to use conical-bearings in a x-figure.
I'm not a machinist, but have a friend who will help with the project.
Looking for info/help/opinion perhaps dxf/pdf drawing of old/new eq mount for bearing/worm location.
I would love to see how Astro-Ph doing the worm/bearing assembly. Can't find any pic on the net.... 
How about old mount like Schafer?
I hope my English is reasonable to describe my quest...
Cheers,
Mick
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roscoe
curmudgeon
Reged: 02/04/09
Loc: NW Mass, inches from VT
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5350776 - 08/03/12 07:58 PM
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Mick,
I've seen them above (scope side), between, and below, the bearings, below: most often, above: second, and between: third. I think it matters mostly to how you are going to mount the bearings, and where there is sufficient space for the drive gear.
Russ
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John Jarosz
Astro Gearhead
Reged: 04/25/04
Loc: Chicago area, IL
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Re: ATM eq mount/Byers worm gear
[Re: roscoe]
#5350800 - 08/03/12 08:18 PM
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i think the location depends on how far past the meridian you want to go. The limiting factor is the entire drive train, not just the worm. The Dec axis may hit the RA motors rather than the RA worm.That's what you need to look at.
John
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Sean Cunneen
Let Me Think
Reged: 08/01/07
Loc: Blue Island Illinois
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Re: ATM eq mount/Byers worm gear
[Re: John Jarosz]
#5350820 - 08/03/12 08:33 PM
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What kind of scope are you building the mount for?
Here is the thread for my mount build:
The Fred Mount
One thing I realy wanted was to have slomo-knobs feed back aong the OTA like the old-style refractors but the more modern way has too many advantages when it comes to balance point and getting the CG as low as possible.
Sean
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: Sean Cunneen]
#5354260 - 08/06/12 04:46 AM
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Thanks guys,
my aim is to build a 40-50 kg loading capacity mount with a quality comparable to the great Byers worm gear....
The mount will be permanently assembled.
Find it frustrating not to see examples of the great eq mounts in parts or drawings.
Wisdom of how to support the worm wheel (Astro-P. trust-bearing?) or grab-screw lock to the shaft (Byers mount?)
Is there a practical collection of knowledge/wisdom of mechanical "good-practise" for EQ mount?
Regards and thanks,
Mick.
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Mirzam
Post Laureate
Reged: 04/01/08
Loc: Lovettsville, VA
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5354443 - 08/06/12 09:02 AM
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I's like to see some discussion of the use of thrust bearings. Pillow blocks are fairly straightforward, but thrust bearings are a bit mysterious (to me at least).
For example, if one had a large welded fork mount, what should the bearing between the fork and the upper RA axis look like?
JimC
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Lynnblac
super member
Reged: 04/06/09
Loc: Arizona
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Re: ATM eq mount/Byers worm gear
[Re: Mirzam]
#5362022 - 08/10/12 04:13 PM
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Jim, You will notice that well engineered mounts have increasing X-sectional dia. as you move from scope to floor. As the pier is the largest, the dec X-section the smallest. The thrust bearing works like as if the axis shaft is effectively the dia of the thrust face, but actually be only 1/6 that dia. Non thrust bearing mount only have the effective X-section of the axle. Also hollow shaft at certain wall thickness are 90% as rigid as solid shafts. Food for thought. Lynn
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don clement
Vendor (Clement Focuser)
Reged: 02/02/11
Loc: Running Springs, California
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Re: ATM eq mount/Byers worm gear
[Re: Lynnblac]
#5362075 - 08/10/12 04:53 PM
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I built a RA single arm fork mounting using a single 8” bore Kaydon Reali-slim X bearing series D with a 1/2x1/2 inch cross-section
http://www.kaydonbearings.com/index.htm?PHPSESSID=7cdee7e1dd58d414e865861dd7de43b2 that takes both radial and thrust loads.
http://clementfocuser.com/images/Cable_Drive_Print.pdf
Note both the housing and shaft are aluminum. Bearing play was minimized and bearing preload was made using this single bearing during assembly by using a thermal difference between housing and bore then injecting Loctite 271 anaerobic adhesive between bearing and aluminum housing.
Don Clement
Edited by don clement (08/10/12 05:06 PM)
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StarWrangler
scholastic sledgehammer
Reged: 09/03/04
Loc: Three Rivers, MI U.S.A>
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5362684 - 08/10/12 11:49 PM
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Hi Mick,
I wil be fallowing this post with interest as I still have my 1960's 6" full dia drive
unit that I want to someday make a nice tracking unit.
Good luck,
Alan O.
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: StarWrangler]
#5362967 - 08/11/12 08:10 AM
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Hi All,
I would be humble to learn from great designers....
I did study as many design available on the net. Unfortunately A-p, Byers, Schefers etc not available for design help.... I'm not try to copy/infringe patients....
big companies can do that without asking silly questions.
I like to see/earn how the big-guys do it.... trust-bearing or conical trust-bearing? Perhaps the worm-wheel running free on ball-bearing and a hub used as a clutch like ASTRO-p? Or is the worm-wheel supported by thrust-bearing, like in Losmandy? Would it be a best practise to mount the Byers-clutched worm wheel in mid-bearing?
Practically, would it be a good idea to dump the Byers clutch and replace with a "Astro-P" drum-hub clutch?
For a ATM with a good worm wheel, what is the "best-practise" ? What is the best way to incorporate a Big Byers worm?
Thanks for you all
Regards,
Mick.
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John Carruthers
Skiprat
Reged: 02/02/07
Loc: Kent, UK
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5363059 - 08/11/12 09:40 AM
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http://www.awrtech.co.uk/oddtopic.htm#WORM
how to set up a worm/wheel.
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don clement
Vendor (Clement Focuser)
Reged: 02/02/11
Loc: Running Springs, California
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5363265 - 08/11/12 12:22 PM
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Quote:
Hi All,
I would be humble to learn from great designers....
For a ATM with a good worm wheel, what is the "best-practise" ? What is the best way to incorporate a Big Byers worm?
Yes learn from great designers... the idea of spring mounting the worm has been around along time from ATM book 2 p372 chapter on Springfield Mounting by Russell W. Porter :
Also it would be useful to glean from ATM book 1 p180 Design of mountings Part III "Fundamentals in the Design of Telescope Mountings; Rigidity" by Russell W. Porter.
The ultimate progression of this thinking leads to the Alt-Az mount found in modern day Dobs where the loads are concentrated totally inboard. In Porter’s day there wasn’t computers or the technology to drive an Alt-Az mount though.
Don Clement
Edited by don clement (08/11/12 01:19 PM)
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: don clement]
#5363705 - 08/11/12 06:03 PM
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Great quotes Don,
is the Astro-P and Schefer mounts are using the two disk method? Placing a free running worm wheel above the two disk and using a "drum-shell" and set-screws as a clutch?
For the ATM put a small trust-bearing between the two large disk and clamping them together, and bearing-balls around the edges where a "trench" machined in the disk.
Just like the Celestron CPC line. The worm wheel can be rest on the top disk with a large trust-bearing and engage on the top pressure plate with the set-screws....
Any comment, drawings....?
Regards Mick
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don clement
Vendor (Clement Focuser)
Reged: 02/02/11
Loc: Running Springs, California
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5363773 - 08/11/12 06:53 PM
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The problem with ball bearings is the nature of the enormous forces derived from the single point contact of the ball. Ball bearing races are made from a hardened material like steel. There was an article in S&T Gleanings (there were alot of very good DIY articles before S&T dropped the Gleanings name) for the ATM IIR in the ‘70s about making a large diameter four point contact ball bearing race (similar to Kaydons Reali-slim X bearing only DIY)using two hardened wires sitting in grooves machined into a soft material such as aluminum.
BTW I don’t see anything wrong with Byers clutches in which he used a series of spring loaded SHCS to apply pressure to a disc. Also Byers used a bearing to support the clutch /worm gear that consisted of a series of ¼” diameter Nylon plugs in a circular pattern and then machined on a lathe so the contact was Nylon on aluminum. No ball bearings were used. His clutches worked pretty darn well. Why change something that has been proven to work very well and is simple to make?
Don Clement
Edited by don clement (08/12/12 11:19 AM)
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: don clement]
#5363844 - 08/11/12 08:00 PM
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I like the way Byers using a "full-face" clutch...not like modern mount using a single point engagement, like EQ6 and Vixen or Tak.....Easier to balance the scope I guess, but the force exerted by the single point of contact must be introduce a distortion on the worm wheel/barrel me think.
In the Byers Series mount the worm wheel is located between the RA north-south bearings. What bearing has been used by Byers? Is it a good idea to locking the pressure plate to the shaft with grab-screws? The worm carriage is floating/spring-loaded, would the grab-screw introduce a "run-out on the worm-wheel?
Regards,
Mick.
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5364281 - 08/12/12 03:49 AM
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I had a "brain-storm" in the shed..... having the Byers gear front of me.... if I keep the original clutch assembly, make a shaft with x-figure tapered-roller bearings.... put the worm wheel in the south, excess-able for balance... and the north bearing can be large(-er) to satisfy Mr Porter suggestion....
I still don't know how the great Astro-P./Scheafer mount work.
Anyone can chip in with description/pics ??
Regards,
Mick.
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TxStars
Pooh-Bah
Reged: 10/01/05
Loc: Lost In Space
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Re: ATM eq mount/Byers worm gear
[Re: Space99]
#5364303 - 08/12/12 04:43 AM Attachment (94 downloads)
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Attached is an PDF sheet showing one way to make a clutch.
This uses an internal clutch shaft with three fingers extending through the RA or dec shaft that apply the force againt the RA or Dec gears via a clutch nut and one spring.
In this design the RA and Dec shafts are held in their housings with a locking nut on the shaft not by the Clutch nut.
If you take the clutch nut off the mount does not come apart.
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TxStars
Pooh-Bah
Reged: 10/01/05
Loc: Lost In Space
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Re: ATM eq mount/Byers worm gear
[Re: TxStars]
#5364311 - 08/12/12 05:15 AM Attachment (40 downloads)
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Excel file:
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neo
Carpal Tunnel
Reged: 02/12/08
Loc: Iasi, Romania
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Re: ATM eq mount/Byers worm gear
[Re: TxStars]
#5364316 - 08/12/12 05:31 AM
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Or you could go the Losmandy way and use the RA shaft as part of the clutch system. So in the North you get the worm wheel resting on a hub with a large axial bearing. The RA shaft (with a big flange in the NOrth) goes through the worm wheel then thru a neelde roller bearing and an angular thrust bearing at the end. Although Losmandy used a needle bearing at the South end too but also used anoher axial bearing for the tighting nut.
But using an angular thrust bearing would be even better for bigger payloads.
http://www.astro.uni-bonn.de/~mischa/mounts/g11_disassembly.html
Here's a russian mount project before going into production wich uses the same principle and the accuracy is absolutely great.
http://www.youtube.com/watch?v=2ZyL0R49NwQ&feature=relmfu
Edited by neo (08/12/12 05:33 AM)
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Space99
sage
Reged: 08/14/08
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Re: ATM eq mount/Byers worm gear
[Re: neo]
#5364327 - 08/12/12 06:15 AM
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Hmmmm..... still don't know how Astro-p and Schafer EQ mount use the bearings....
What would be the best practice to use the great Byers worm gear?
Guys, put the collected wisdom to good use.... make it a "sticky" post.... not that many Byers worm Wheel/clutch on the market... pros'n-cos... best practise...
Pics-drawings-plans-dxf-pdf.......
A bearing her'n there nowadays is cost nothing compare to what you can achieve.... it's the principle...
(sorry from the lack of perfect English.... )
Like to here from you
Mick.
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