A Fine-Focus Knob For A Crayford

[Dave In Vermont]

I had the dreaded "Gotta Have It!" moments when I ran into the fine-focus knob while wandering about in ScopeStuff.com. That place will get you too if let it. And I let it! As many of you know, I've recently been fine-tuning my little ST80 Refractor. It started with my disdain forthe visual-back and R&P focuser on it. My first step was to disassemble it and clean off whatever was used on the focuser by the factory it came from. It was like a mixture of glue and dried-out rubber-cement.

Even though my re-packing the focuser with teflon-based bicycle-grease made a huge difference, I'd caught the "Gotta Have It!" virus. So I caved in - time to admit my disease and accept condition. So I ordered a GSO Crayford that would fit the ST80 like a glove. And this made an exponential difference. So it went: A very nice GSO 8 X 50mm RACI replaced the 6 X 26mm toy-finder the scope came with. A Helio-Pod adorned the front. A nasty optical defect resulted in a new scope..... So when I ran into the fine-focusing knob, I surrendered without a struggle!

This knob fits was made to fit the small 1:10 knob on the stock GSO. ScopeStuff has many others that fit many other focusers. And I had long-used one on my Meade LX200, and then LX90, until replaced with a JMI Moto-Focus for the LX90. And it fit fine - and I was quite surprised to find it actually made a huge difference. The focuser could be dialed-in with a scalpel-like finesse, and for some unknown reason, I can spin the focus-knobs and they keep spinning-smooth without my touching it. Never did that before - I'm still mystified by this new behavior.

This trick of using a larger knob has been known to many for decades.I've even seen people who use lids off jars of peanut-butter. I opted for the 'Bling!' factor and went for the ScopeStuff offering. It works on the same principle as an old LP record on a turn-table where the inside of the record is spinning faster than the outer-edge. Or so it would appear. Using a larger knob on a focuser does cause a palpable difference.

Anywho, pictures are below.

Dave