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Primary Heavy duty springs


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4 minutes ago, bottletopburly said:

I want to put one where the locking screw is 

any reason to do that?

Thing is that adding an extra spring would mean the main collimation screws have more load to compress and you potentially risk stripping the thread in the mirror carrier if making adjustments that require the springs to be compressed a lot.

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13 minutes ago, DaveL59 said:

any reason to do that?

Thing is that adding an extra spring would mean the main collimation screws have more load to compress and you potentially risk stripping the thread in the mirror carrier if making adjustments that require the springs to be compressed a lot.

@alacant done it  on his and recommended it so good enough reason for me .

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4 hours ago, bottletopburly said:

put one where the locking screw is 

Well done.

You're on your way to a Newtonian which holds collimation at all tube angles, not just the one at which you collimated.

One less thing to have to compensate for:)

Edited by alacant
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48 minutes ago, bottletopburly said:

1.6mm dia

For 200mm mirrors, we use 1.6mm. This covers all 200mm SW possibilities, including the older thick Pyrex glass type.

You'll find that if the mirror is held to prevent lateral motion by silicone, you'll rarely need to touch the adjusters.

Cheers

Edited by alacant
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21 hours ago, bosun21 said:

Why six?

Hi

We've yet to find a low end reflector -the ones with with three weak springs- hold collimation at varying tube angles.

Cheers and HTH

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Just use the locking screws for what they were intended for…….locking the collimation. Then the springs are irrelevant. After tightening the locking screws you may have to fine tune the collimation using only the locking screws. A method I’ve always used and the scope holds perfect collimation for a very long time.

Edited by johninderby
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1 hour ago, alacant said:

Hi

We've yet to find a low end reflector -the ones with with three weak springs- hold collimation at varying tube angles.

Cheers and HTH

It only needs the three springs upgraded. It’s pointless placing springs on the locking screws IMHO

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12 minutes ago, bosun21 said:

It only needs the three springs upgraded. It’s pointless placing springs on the locking screws IMHO

Well I’ve ordered a pack of 10 so no big deal I’ll see what it’s like

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2 hours ago, bosun21 said:

pointless placing springs on the locking screws

We didn't think so either until we tried with and without. No obligation of course, but making an astrograph from a bottom of the range Newtonian, you need every bit of help you can get.

Of course, the locking screws are left in place merely to retain the extra springs; loose.

@laser_jock99 is the pioneer of the technique. All credit to him.

Cheers

 

Edited by alacant
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I totally agree that the springs on mass produced Newtonians should be replaced in order to maintain collimation. I bought the Bob’s Knobs replacement springs for my 8” dobsonian and the difference is obvious. It now holds its collimation and i very seldom need to make adjustment. The difference in the springs is obvious 

 

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On 26/06/2022 at 13:36, johninderby said:

Just use the locking screws for what they were intended for…….locking the collimation. Then the springs are irrelevant. After tightening the locking screws you may have to fine tune the collimation using only the locking screws. A method I’ve always used and the scope holds perfect collimation for a very long time.

I learnt this method by trial and error. I’ve said it before but I wish I’d known/been told about it earlier. 

I last collimated my Skywatcher Skyliner Dob in April. And all that has is rubber washers - no springs at all. I use this telescope very regularly and I haven’t needed to fiddle with the primary adjustments since then. Mind, I just take it in/out to my garden. Travelling by car might then mean it needs attention. 

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Need to have a look at springs for when I get a 130pds later in the year.

  Seems a cheap and easy upgrade to make life a lot easier.

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I replaced my 12"'s springs with the ones from Bob's Knobs. It makes a huge difference. The originals were too soft and the whole cell assembly would clunk, groan and shift when collimating and moving the scope. There was no way to keep collimation as it was. Now it's much easier to collimate and stays in position. I do tighten the locking bolts once collimated though and use them as a final 'fine tune'.

271179519_DSC_0226_DxO1200.jpg.46c0d7ed2fe05e3b22341f213211fe2a.jpg

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1 hour ago, Mr Spock said:

I replaced my 12"'s springs with the ones from Bob's Knobs. It makes a huge difference. The originals were too soft and the whole cell assembly would clunk, groan and shift when collimating and moving the scope. There was no way to keep collimation as it was. Now it's much easier to collimate and stays in position. I do tighten the locking bolts once collimated though and use them as a final 'fine tune'.

271179519_DSC_0226_DxO1200.jpg.46c0d7ed2fe05e3b22341f213211fe2a.jpg

That’s exactly what I do also. I tighten the locking screws in a sequence that keeps the collimation bang on just like a final fine tune. The Bobs knobs springs are ideal and I don’t know why FLO doesn’t stock them.

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