Fitting SW accu motor to 10:1 Crayford

[Merlin66]

I use the SW accufocus motors on almost all of my gear - cheap and does the job well. I have these focuser motors on my ED80 for Ha solar imaging and the C11 for spectroscopy...
Just before I left Belgium I managed to aquire a Baader Herschel Wedge and a TS 102 f11 Achromat.
The TS102 has been converted to a modded PST as well.
This scope has the generic 10:1 Crayford and I needed a fine focus control for solar imaging.
The attached images show the set-up:
Based on the Std SW/Orion focuser motor...
I already had a 28 tooth wheel and 80 tooth belt from another project (!!)
I measured the "gap" below the Crayford body as 9mm and found a piece of MDF and a 1.6mm aluminium plate which stacked up.
By removing the two small M3 screws from the base of the Crayford and drilling a 6mm diameter hole ( to clear the locking screw) I managed to come up with a pretty compact solution.
Pretty self evident, but works very, very well for fine focusing with the DMK camera.
Any questions let me know.

[Astro_Bot]

Looks good! :thumbsup:

Do you remember where you got the belt and wheel? Thanks.

[Merlin66]

Yeah, I think they came from Motion Control in the UK (when I was there).
I'm sure you can get something similar locally.....
I should have said the belt just drops off for rough focusing with the main knobs....

[Merlin66]

A Photo of the finished item....
Works even better than anticipated. Smooth, very fine focus control - just what you need for solar imaging.
Strongly recommended.

[mswhin63]

Hi Ken, I was looking at the same thing with mine as well, just never got around to it. The knobs have great gearing for the tiny belts. :thumbsup:

[Merlin66]

It's a well worth project for anyone who wants precision focusing (don't we all??) very easy and very cost effective......

[Garnimoa]

Hi Ken,

I have purchased the Bintel 10: 1 focuser for my ED100 as well as the Electric Focuser motor (the website said that it came with the adapter) but it doesn't and talking to Bintel, it seems like that info shouldn't be on there apparently!

Anyway I thought I would keep the motor and try to make an adapter plate myself, but dont know where to start. Do you have any advice on this?

These are the parts I bought:
Motor - https://www.bintel.com.au/product/skywatcher-electric-focus-motor/
and the Crayford 10:1 focuser: https://www.bintel.com.au/product/bintel-crayford-focuser-101-refractor-96mm-od/

Cheers Gerald :)

[Merlin66]

Gerald,
See the images below for detail.....
Basically a 80 tooth belt and a 30 tooth pinion....Small parts Aust.
A small aluminium plate drilled to match the focuser and a 6mm MFD spacer...

You're welcome to pop over to St Leonards to see the focuser(s) in action.

[AstroApprentice]

Great mod Ken, I particularly like the motor position rather than sticking way out to one side as is usually the case when using the shaft coupler.

Gerald - I’d call Bintel again. I bought the same motor for my ED120 and it came with a mounting bracket. The coupler was the wrong size, so they sent me one that fits at no extra charge.

[Garnimoa]

Thanks Ken,
When would suit you, to pop over?

Cheers Gerald :)

[Merlin66]

PM sent.

[ChrisV]

Ken
You used MXL belt/pulley. Any reason - does it fit over a focuser knob better?
Chris

[Merlin66]

Readily available, and the one I used back in the Uk.
But, yes, it fits the knurled knobs on standard focuser.

[JimsShed]

Thanks for this Ken. I think I’m inspired !

[Merlin66]

Jim,
I've just added the same drive system to the Crayford on the PST Mod.
Works very well.
http://www.iceinspace.com.au/forum/showthread.php?t=165783

[raymo]

Mine came with adaptor plates to suit both of the focusers commonly used
on SW scopes. Worked great for years, until I sold the scope.
raymo

[Merlin66]

Yeah,
For the standard (older) single speed Crayford the supplied adaptors work well.
To get precise focusing with the 10:1 version ideally the SW motor should drive the 10:1 drive - this seems to be easier with a mini-belt drive arrangement.

[miker]

Hi Ken,

"I use the SW accufocus motors on almost all of my gear - cheap and does the job well. I have these focuser motors on my ED80 for Ha solar imaging and the C11 for spectroscopy..."

I have recently purchased a new C11 and would like to add this motor focus unit from Bintel.

Would you be able to provide some detail/pictures of the way you mounted it to the C11.

Any info would be greatly appreciated.

Michael

[Merlin66]

The motor was fitted with a 30 tooth XML pulley and a 80 tooth XML belt used.
(Both pulley and belt(s) can be sourced from Small Parts, QLD.)
A small aluminium bracket was made up to mount the motor and attach to the telescope using the finder screws....

Worked very well for me. I also used the Shoestring FCusb module for remote control. I eventually replaced the motor with a JMI motor and re-used the pulley/ belt arrangement on the spectroheliograph.

If you need more info (I'm sure I still have the bracket I made up in the observatory....) let me know.
(The yellow Vegemite lid in the background was my "original" fine focusing set-up.)

[miker]

Thanks for the detailed reply. I will start putting this together.
Using the finder screw holes looks like a good mounting point.
I have a Telrad and have not fitted the finder.
I appreciate your reply.:thumbsup:

Michael