SW Craydord Dual Mod

[sbooder]

Hi All,

has anyone taken the SW Dual speed Crayford apart yet to do the barrel flat mod yet?

I ask because I have never seen so many hex screws on the underside of focuser in my life...I realise that the two centre ones are the tension adjusters (I think?) but do I need to undo all the others to take off the dual speed engine?

[jam1e1]

i just spent hour or so doing it! Well tuning it, there is a good link on this post: http://stargazerslounge.com/equipment-help/131608-ds-focuser-broken.html

you prob only need undo the 4 corner ones and possibly the centre one, either way they can be easily done up again. Note you may need to adjust it slightly when you put back to get pressure and grip right - i never done it before but got there in end

[sbooder]

Thanks,

I am going to go for it...I will let you know the outcome.

[John]

Careful not to over-tighten the hex screws - I tried to "improve" one of those last year and managed to ruin it by over-tightening a hex screw which bent the 1:10 gearing housing a little out of shape. The focuser never worked properly again

[jam1e1]

cheers will take note.

BTW, does anyone know where to get replacement hex screws from, also need a new thumbscrew tension knob too.....

[sbooder]

OK, I have done the mod and worked out all the hex heads on the underside. Here is a key photo to show their functions.

[swag72]

Is the A hex purely for attaching the focuser then? I was sorting out my focuser last night (hope I've sorted it) but found that adjusting A's made a big difference. If they are purely for attachment, then turning them should not make any difference?

[sbooder]

What I did was have both B and C hex undone almost all the way, did up the A hex firmly and then used both A and B to adjust the tension until the feel and tension was right.

[sbooder]

Well I had a cracking night last night; it was the sort of day dreams are made of. England beat France, in the Six Nations, and it was one of the best skies for a long time.

It gave me plenty of tuned up Crayford time and it works a treat now, very smooth.

[jam1e1]

For anyone interested, if you need new hex bolts they are:

M3 x 8 mm Hex socket screws

If you need new thumbscrew:

M5 X 20 mm METAL THREAD THUMB SCREW

The thumbscrews may need a blob of glue on top as a soft edge so doesnt score the focus tube, either way I now own 10 so certainly wont go short!

Do a google or ebay search to find.

[swag72]

Are the hex screws coutersunk like these or like these?. I'm going to get a few just incase!

[sbooder]

Are the hex screws coutersunk like these or like these?. I'm going to get a few just incase!

No, they are slightly dome headed and protrude a little.

[swag72]

Must be these ones then?

[sbooder]

Similar

[swag72]

These ones will work though, will they?

[sbooder]

I presume so. Although the ones on the focuser are not countersunk so flush, the heads to enter the top of the hole. So if you get ones that have a larger head that will not fit the hole, the thread may not be long enough. I will take one out later and photograph and measure it for you.

[swag72]

Thanks Simon - I think these are useful to have around as the hex head has got a little worm on one of mine.

[sbooder]

OK, the Hex that attach the focuser engine to the underside of the focuser are 6.5mm from top of the hex head to the bottom of the thread, the thread is 4.5mm long and is a 3mm thread.

[swag72]

I have contacted the seller with those sizes to confirm. Perhaps anyone else reading this can tell me where they purchased some of these screws? Cheers folks.

[sbooder]

I forgot to say that the head size across the base is 5mm

[jam1e1]

the last link found looks like them, first two links were not. by accident i bought the 10mm but they still fit fine. These are the ones: M3 x 8mm 3 x 8 Black Inner Hex Button Socket Screw x 10 on eBay (end time 16-Mar-11 14:31:39 GMT)

no pic but i bought the 10mm versions:

M3 x 10mm 3 x 10 Black Inner Hex Button Socket Screw 10 on eBay (end time 16-Mar-11 14:29:31 GMT)

[jam1e1]

btw it was blacksmithproducts from ebay, bought one day arrived next day: eBay My World - blacksmithproducts