Using 67PF562 flattener with 130 F6.3 GT


drgert1
 

Hello All,

I am looking for info on how people establish the imaging train of 130 F6.3 GT with 67PF562 flattener? Esp. how things proceed from the end of the flattener downstream. Somebody have photos? The flattener is full of glass so sticking a 2inch camera nose piece there wont work.  My camera is ASI2600MM with EFW and OAG M68.

Clear Skies,
Gert


Robert
 

On Thu, May 20, 2021 at 12:49 AM, drgert1 wrote:
67PF562
Have you seen this yet?

https://www.astro-physics.info/tech_support/accessories/photo_acc/67pfdiagram.pdf

Robert


Jeffc
 

With the QHY268M+FW on the 67PF562 I have settled on this combo…

67PF562 + Flange to go to 2.7” thread + Baader 2.7” to M68 + M68 to M48 then the filter wheel with an M48 thread.  

(Apologies I don’t have exact number for the “flange”.. it is iirc the “CCD adapter”.. which are available in different heights.  This one is fairly short.)

(In the pic below the baader parts I’m pointing at are together.   I wasn’t able to separate them.  That’s the 2.7” to M68 and M68 to M48.)

M48 is not ideal.. I’d prefer M54 but would need to go custom.  Also, my spacing might be slightly off.  I’m still working on testing the focus.  

I did use the baader 2” nose piece with the compression part shown in the picture.  
The ones that came with the camera seemed like they would hit the glass but I also noted the glass is curved so the distance is larger at the edge of the ring. 

It seems if you have M68 so you might just need the baader 2.7” to M68.

Fwiw I’m not sure the OAG will allow for the correct spacing.  I poured over the ASI 2600mm a while back , but it was backordered forever so went with the QHY. 

 


On May 19, 2021, at 11:49 PM, drgert1 via groups.io <drgert1@...> wrote:



Hello All,

I am looking for info on how people establish the imaging train of 130 F6.3 GT with 67PF562 flattener? Esp. how things proceed from the end of the flattener downstream. Somebody have photos? The flattener is full of glass so sticking a 2inch camera nose piece there wont work.  My camera is ASI2600MM with EFW and OAG M68.

Clear Skies,
Gert


drgert1
 
Edited

@jeffc

Thank you! This is helping me a few steps further along.

So the spec on the AP website for the 67PF562 doesn't say clearly what's the in / out specs.

The scope side (short knurled ring) is male 2.74x24 (can someone confirm?)
The camera side (longer knurled ring) (ring does actually what?) ??

The 'flange' is a bit of a mystery to me. Is it i.e. AP part # A1260 ??
https://www.astro-physics.com/a1260

How does that get locked to the flattener? On the camera side of the 'flange' there's female 2.74x24.

Does that mean that to 'fill the back focal length' on the camera side can I use regular AP 2.7inch extension pieces?  (I.e. the ones sold by Optecf?)
https://www.optecinc.com/astronomy/ap_2.7_adapters.htm

But then I need an adapter female 2.74x24 to M68x1 male (The M68 OAG has female threads).
There is this one.
https://www.highpointscientific.com/baader-planetarium-2-7-ap-external-to-m68-zeiss-internal-adapter-m68-ap-e?utm_source=google&utm_medium=cse&utm_term=BAD-M68/AP-E&gclid=Cj0KCQjwkZiFBhD9ARIsAGxFX8BbDTmwJSdPbaeO7Mu4jnXTt1bvVGj4Q3pRIC6NgbTZnvjVeuhAjEQaAiKkEALw_wcB

But it's from AP2.7inch male to M68 female. Exactly the opposite of what I need.

Anyone can help clarify?

Thanks,
Gert


M Hambrick
 

Hi Gert

Can you post a picture of your flattener where we can see what is on the camera side ?

Mike


Jeffc
 



On Thu, May 20, 2021 at 4:18 PM drgert1 via groups.io <drgert1=yahoo.com@groups.io> wrote:

[Edited Message Follows]

@jeffc

Thank you! This is helping me a few steps further along.

So the spec on the AP website for the 67PF562 doesn't say clearly what's the in / out specs.

Is this what you're looking for?

>>> The backfocus spacing for these flatteners (as measured from the rear flange) is 3.4" +/- 1/10" (86.4 mm +/- 2.5 mm).


The 'flange' is a bit of a mystery to me. Is it i.e. AP part # A1260 ??
https://www.astro-physics.com/a1260


yes I think it is this part.  The A1260 is called out on this diagram:  https://www.astro-physics.info/tech_support/accessories/photo_acc/67pfdiagram.pdf 


The scope side (short knurled ring) is male 2.74x24 (can someone confirm?)

The above "scope side" would be the part that goes in the focuser drawtube.   You should be able to just screw it in.
( Here's a list of common threads with Astro-Physics listed:  https://agenaastro.com/articles/guides/miscellaneous/astronomy-threads-explained.html#more )

The camera side (longer knurled ring) (ring does actually what?) ??

The knurled ring holds the A1260 (or other camera adapters) in place.  The knurled ring allows for loosening the flange a bit and rotating the camera for framing.   (Tho I dont use this feature as my camera / filterwheel is not "center balanced" and I like to keep things balanced.)

The knurled ring unscrews, and the A1260 sits on the flattner surface, and the ring then threads back on tightening down on the A1260.



How does that get locked to the flattener? On the camera side of the 'flange' there's female 2.74x24.

Ok.. it seems like there might be something like a A1260 already on flattner. 

(I agree with MIke:  Post a picture.   Does it look like the picture I posted?)


Does that mean that to 'fill the back focal length' on the camera side can I use regular AP 2.7inch extension pieces?  (I.e. the ones sold by Optecf?)
https://www.optecinc.com/astronomy/ap_2.7_adapters.htm

I think so.  (the spacers should be simple male on one end and female on the other.)  
For me, i'm already too far back (afaict) and need to get the QHY268m+FW camera closer to the 67PF562.

But then I need an adapter female 2.74x24 to M68x1 male (The M68 OAG has female threads).
There is this one.
https://www.highpointscientific.com/baader-planetarium-2-7-ap-external-to-m68-zeiss-internal-adapter-m68-ap-e?utm_source=google&utm_medium=cse&utm_term=BAD-M68/AP-E&gclid=Cj0KCQjwkZiFBhD9ARIsAGxFX8BbDTmwJSdPbaeO7Mu4jnXTt1bvVGj4Q3pRIC6NgbTZnvjVeuhAjEQaAiKkEALw_wcB

That is exactly the adapter I purchased and showed in my picture with my finger.   (I also have another adapter on top to get to M48 tho.)

But it's from AP2.7inch male to M68 female. Exactly the opposite of what I need.

You want the adapter-attached-to-the-camera to be male.    Assuming there is a part like the A1260 on the flattner, and the camera side of the flattner is the end with the knurled ring.. with the A1260 in place :   a 2.7" female AP thread will be exposed.    

That Baader M68/AP-E part will screw into the AP 2.7" threads and expose a Female M68 thread.

Does the OAG have female threads?  If so, then I think you will need a M68 male-male adapter to use the Baader M68/AP-E.
e.g.

Welcome to "adapter hell".  B^)

Hopefully this doesn't muddy the waters more.   The ASI2600mm is a popular camera (afaict) and there should be more knowledge of how to hook it up and get the spacing correct.   Another route is to get an adapter from precise parts, but i shudder at lead time.


Anyone can help clarify?

Thanks,
Gert


drgert1
 

Hi Mike, Hi Jeffc,

Thank you again for the ton of information. That helped me a lot.

@Mike I don't have the flattener (yet). Today I am using a 'generic' refractor flattener from 'Telescope Service'. (And contemplating if I should upgrade)
https://www.teleskop-express.de/shop/product_info.php/info/p10307_TS-Optics-REFRACTOR-1-0x-Flattener-and-Field-Corrector---2--connection.html

@Jeffc Thank you for helping me with the AP flattener. I got following understanding.
  • Scope side of 67PF562 is AP2.7 male thread to thread into the focuser. Great!
  • Camera side has flange with knurled lock ring to 'clamp' adapter AP part # A1260 (or similar with different length)
  • AP adapter part # A1260 provides Ap2.7inch female thread to camera side. (just the same as if it were the focuser end piece)
  • Next is adapter to 68mm x1.0
    https://agenaastro.com/baader-m68-female-to-2-7-male-zeiss-astro-physics-thread-adapter-m68-ap-e-2458220.html
  • The ZWO OAG has indeed M68x1.0 female. So I need a male-male adapter
    https://agenaastro.com/baader-m68-conversion-ring-gender-changer-m68-male-male-adapter-m68-inve-2458194.html
  • That will connect to the ZWO OAG M68. (Perfect!)
I got on the 2600MM 'package deal' that came out a while back which includes the camera, a new EFW Mark II (with bolt connection to camera!), and the 'large' OAG M68 (also with bolt on connection to the EFW). Today I have a M68 to 2inch nosepiece adapter and then the 'TS' flatter at its respective design distance (by means of 2inch M48x0.75 extension)

The above is working OK. My concern was:
  • Vignetting from the 2inch nosepiece (I need to check flats to validate) (though clearly 2.7inch is more than 2inch :-) )
  • Native optical quality of the 'generic' flattener.

Leads to a question. I know that the history of the AP flattener goes back to the medium format Pentax photography days. In the days film grain was way larger than today's sensor pixels. Do we know if AP has evolved the flattener to work with 3.76um pixels of the 2600MM accross the APS-C size sensor?

Thanks & Clear Skies,
Gert


ROBERT WYNNE
 

I Believe based upon past information posted on this board what I have gathered is that an ideal match depends upon the minimum size of the airy disc capability of your scope to the minimum pixel dimensions of your camera. The rule of thumb has currently been no smaller than 3.7 microns for camera pixels to 7 microns. Though all is dependent upon the minimum diameter of of your scope's airy disc. The two dimensions should match as closely as possible for the best result. I defer to the experts on this one however. -Best, Robert

On 05/20/2021 7:37 PM drgert1 via groups.io <drgert1@...> wrote:
 
 
Hi Mike, Hi Jeffc,

Thank you again for the ton of information. That helped me a lot.

@Mike I don't have the flattener (yet). Today I am using a 'generic' refractor flattener from 'Telescope Service'. (And contemplating if I should upgrade)
https://www.teleskop-express.de/shop/product_info.php/info/p10307_TS-Optics-REFRACTOR-1-0x-Flattener-and-Field-Corrector---2--connection.html

@Jeffc Thank you for helping me with the AP flattener. I got following understanding.
  • Scope side of 67PF562 is AP2.7 male thread to thread into the focuser. Great!
  • Camera side has flange with knurled lock ring to 'clamp' adapter AP part # A1260 (or similar with different length)
  • AP adapter part # A1260 provides Ap2.7inch female thread to camera side. (just the same as if it were the focuser end piece)
  • Next is adapter to 68mm x1.0
    https://agenaastro.com/baader-m68-female-to-2-7-male-zeiss-astro-physics-thread-adapter-m68-ap-e-2458220.html
  • The ZWO OAG has indeed M68x1.0 female. So I need a male-male adapter
    https://agenaastro.com/baader-m68-conversion-ring-gender-changer-m68-male-male-adapter-m68-inve-2458194.html
  • That will connect to the ZWO OAG M68. (Perfect!)
I got on the 2600MM 'package deal' that came out a while back which includes the camera, a new EFW Mark II (with bolt connection to camera!), and the 'large' OAG M68 (also with bolt on connection to the EFW). Today I have a M68 to 2inch nosepiece adapter and then the 'TS' flatter at its respective design distance (by means of 2inch M48x0.75 extension)

The above is working OK. My concern was:
  • Vignetting from the 2inch nosepiece (I need to check flats to validate) (though clearly 2.7inch is more than 2inch :-) )
  • Native optical quality of the 'generic' flattener.

Leads to a question. I know that the history of the AP flattener goes back to the medium format Pentax photography days. In the days film grain was way larger than today's sensor pixels. Do we know if AP has evolved the flattener to work with 3.76um pixels of the 2600MM accross the APS-C size sensor?

Thanks & Clear Skies,
Gert


Jeffc
 

For the GT 2.7” focuser I believe the only flattner that will work (from AP) is the 67PF562.   

For the GTX 3.5” focuser there is the 13035FF, tho is appears this uses the same optics as the 67PF562. 

Someone with more experience of the AP optics can confirm. 


On May 20, 2021, at 7:38 PM, drgert1 via groups.io <drgert1@...> wrote:

Hi Mike, Hi Jeffc,

Thank you again for the ton of information. That helped me a lot.

@Mike I don't have the flattener (yet). Today I am using a 'generic' refractor flattener from 'Telescope Service'. (And contemplating if I should upgrade)
https://www.teleskop-express.de/shop/product_info.php/info/p10307_TS-Optics-REFRACTOR-1-0x-Flattener-and-Field-Corrector---2--connection.html

@Jeffc Thank you for helping me with the AP flattener. I got following understanding.
  • Scope side of 67PF562 is AP2.7 male thread to thread into the focuser. Great!
  • Camera side has flange with knurled lock ring to 'clamp' adapter AP part # A1260 (or similar with different length)
  • AP adapter part # A1260 provides Ap2.7inch female thread to camera side. (just the same as if it were the focuser end piece)
  • Next is adapter to 68mm x1.0
    https://agenaastro.com/baader-m68-female-to-2-7-male-zeiss-astro-physics-thread-adapter-m68-ap-e-2458220.html
  • The ZWO OAG has indeed M68x1.0 female. So I need a male-male adapter
    https://agenaastro.com/baader-m68-conversion-ring-gender-changer-m68-male-male-adapter-m68-inve-2458194.html
  • That will connect to the ZWO OAG M68. (Perfect!)
I got on the 2600MM 'package deal' that came out a while back which includes the camera, a new EFW Mark II (with bolt connection to camera!), and the 'large' OAG M68 (also with bolt on connection to the EFW). Today I have a M68 to 2inch nosepiece adapter and then the 'TS' flatter at its respective design distance (by means of 2inch M48x0.75 extension)

The above is working OK. My concern was:
  • Vignetting from the 2inch nosepiece (I need to check flats to validate) (though clearly 2.7inch is more than 2inch :-) )
  • Native optical quality of the 'generic' flattener.

Leads to a question. I know that the history of the AP flattener goes back to the medium format Pentax photography days. In the days film grain was way larger than today's sensor pixels. Do we know if AP has evolved the flattener to work with 3.76um pixels of the 2600MM accross the APS-C size sensor?

Thanks & Clear Skies,
Gert


Jeffc
 

Gert - it sounds like you got it figured out… 
But I went ahead and made a couple videos of the 67PF562 assembly.   

1) The first is showing how the Canon camera adapter attaches.  

2) The second shows the “A1260” CCD adapter flange ring with 2.7” thread , and attaching the 2” compression adapter.  
 The baader 2.7” to M68 attaches the same way as the 2” adapter but I don’t show it in the video.   
At the end of the video I show the part that goes into the focuser drawtube. 


(Ping me if these aren’t visible/available for some reason.)


On May 20, 2021, at 7:38 PM, drgert1 via groups.io <drgert1@...> wrote:

Hi Mike, Hi Jeffc,

Thank you again for the ton of information. That helped me a lot.

@Mike I don't have the flattener (yet). Today I am using a 'generic' refractor flattener from 'Telescope Service'. (And contemplating if I should upgrade)
https://www.teleskop-express.de/shop/product_info.php/info/p10307_TS-Optics-REFRACTOR-1-0x-Flattener-and-Field-Corrector---2--connection.html

@Jeffc Thank you for helping me with the AP flattener. I got following understanding.
  • Scope side of 67PF562 is AP2.7 male thread to thread into the focuser. Great!
  • Camera side has flange with knurled lock ring to 'clamp' adapter AP part # A1260 (or similar with different length)
  • AP adapter part # A1260 provides Ap2.7inch female thread to camera side. (just the same as if it were the focuser end piece)
  • Next is adapter to 68mm x1.0
    https://agenaastro.com/baader-m68-female-to-2-7-male-zeiss-astro-physics-thread-adapter-m68-ap-e-2458220.html
  • The ZWO OAG has indeed M68x1.0 female. So I need a male-male adapter
    https://agenaastro.com/baader-m68-conversion-ring-gender-changer-m68-male-male-adapter-m68-inve-2458194.html
  • That will connect to the ZWO OAG M68. (Perfect!)
I got on the 2600MM 'package deal' that came out a while back which includes the camera, a new EFW Mark II (with bolt connection to camera!), and the 'large' OAG M68 (also with bolt on connection to the EFW). Today I have a M68 to 2inch nosepiece adapter and then the 'TS' flatter at its respective design distance (by means of 2inch M48x0.75 extension)

The above is working OK. My concern was:
  • Vignetting from the 2inch nosepiece (I need to check flats to validate) (though clearly 2.7inch is more than 2inch :-) )
  • Native optical quality of the 'generic' flattener.

Leads to a question. I know that the history of the AP flattener goes back to the medium format Pentax photography days. In the days film grain was way larger than today's sensor pixels. Do we know if AP has evolved the flattener to work with 3.76um pixels of the 2600MM accross the APS-C size sensor?

Thanks & Clear Skies,
Gert


drgert1
 

@Jeffc,

The video is excellent. I can fully see what the idea was at AP to organize the camera connections. I see that the camera side of the flattener plus adapter is AP 2.7inch thread. From there onward I'll have to get the adapter to the M68 OAG. This is great material!

Thanks,
Gert


M Hambrick
 

Hi Gert

I want to offer a lesson learned about the flanged connections like those that are used on the ADA1260.

I have an imaging arrangement where I am using a flanged connection with an ADA671 and ADA2767 which is essentially the same concept as the ADA1260. I have found that once the locking ring is tightened the two pieces have a tendency to get locked very tightly together to the point that they can not be unscrewed without some kind of leverage. 

If you do not already have any strap wrenches you should consider getting some. You will need two of them. One provides the leverage on the locking ring, and the other serves as the backup on the ADA1260. The ones with the plastic handle and rubber strap will minimize any risk of damaging the aluminum parts. Amazon has quite a few to pick from, and they are not expensive (typically less than $10). 

Mike


Jeffc
 

> If you do not already have any strap wrenches you should consider getting some. You will need two of them. 

Indeed.   In fact just before I took those videos I needed to use the rubber strap wrench to get the knurled ring off.
I only have one strap wrench, which I placed around the knurled ring and held the flattner on a microfiber cloth.
(I'm thinking of getting another.)

-jeff

On Fri, May 21, 2021 at 4:18 PM M Hambrick <mhambrick563@...> wrote:
Hi Gert

I want to offer a lesson learned about the flanged connections like those that are used on the ADA1260.

I have an imaging arrangement where I am using a flanged connection with an ADA671 and ADA2767 which is essentially the same concept as the ADA1260. I have found that once the locking ring is tightened the two pieces have a tendency to get locked very tightly together to the point that they can not be unscrewed without some kind of leverage. 

If you do not already have any strap wrenches you should consider getting some. You will need two of them. One provides the leverage on the locking ring, and the other serves as the backup on the ADA1260. The ones with the plastic handle and rubber strap will minimize any risk of damaging the aluminum parts. Amazon has quite a few to pick from, and they are not expensive (typically less than $10). 

Mike


ROBERT WYNNE
 

Ha! I am the idiot who backed his alignment scope lens all the way in and then locked the locking ring snug over the fully retracted lens. Even with strap wrenches I was unable to part the locking ring and returned to A-P who graciously unlocked the assembly. I now have done it once again and with the aid of strap wrenches am still unable to break the locking ring. Back to A-P. I did not try this brand of strap wrench. My problem was that the straps would slip before a good cinch could be obtained. Good luck with with these. -Best, Robert

On 05/21/2021 4:18 PM M Hambrick <mhambrick563@...> wrote:
 
 
Hi Gert

I want to offer a lesson learned about the flanged connections like those that are used on the ADA1260.

I have an imaging arrangement where I am using a flanged connection with an ADA671 and ADA2767 which is essentially the same concept as the ADA1260. I have found that once the locking ring is tightened the two pieces have a tendency to get locked very tightly together to the point that they can not be unscrewed without some kind of leverage. 

If you do not already have any strap wrenches you should consider getting some. You will need two of them. One provides the leverage on the locking ring, and the other serves as the backup on the ADA1260. The ones with the plastic handle and rubber strap will minimize any risk of damaging the aluminum parts. Amazon has quite a few to pick from, and they are not expensive (typically less than $10). 

Mike


M Hambrick
 

I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike


Jeffc
 

I’m not familiar with metals and thread sizing except from the perspective of experiencing stuck parts.  

I also wonder if “anti-sieze” would be appropriate..  I feel like this would potentially get on optics near the part. 

On May 22, 2021, at 7:48 AM, M Hambrick <mhambrick563@...> wrote:

I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike


Manusfisch
 

I keep a carpenters flat pencil and make a run around the leading threads Taking great care not to allow particles to fall into the optics it’s pretty easy and makes for easier starting and easier removal certainly takes the squeaks out and I keep my strap wrenches nearby

TJF Mobile

On May 22, 2021, at 11:29, Jeffc <jeffcrilly@...> wrote:

I’m not familiar with metals and thread sizing except from the perspective of experiencing stuck parts.  

I also wonder if “anti-sieze” would be appropriate..  I feel like this would potentially get on optics near the part. 

https://www.westmarine.com/buy/star-brite--anti-seize-thread-lubricant--15067002


On May 22, 2021, at 7:48 AM, M Hambrick <mhambrick563@...> wrote:

I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike


ROBERT WYNNE
 

I would be very suspect to use any anti-siezing compound near optics. This is due the introduction of fine metallic particles that make the compound "anti- siezing" even graphite from a "lead" pencil. Anything harder than the lens or coating used as a lubricant is potentially detrimental/destructive to the optics. -Best, Robert

On 05/22/2021 8:29 AM Jeffc <jeffcrilly@...> wrote:
 
 
I’m not familiar with metals and thread sizing except from the perspective of experiencing stuck parts.  
 
I also wonder if “anti-sieze” would be appropriate..  I feel like this would potentially get on optics near the part. 
 
https://www.westmarine.com/buy/star-brite--anti-seize-thread-lubricant--15067002

 

On May 22, 2021, at 7:48 AM, M Hambrick <mhambrick563@...> wrote:

I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike


DFisch
 

Robert I started using lead graphite pencils on the threads about 10 years ago. I’ve never seen any particles that really fall to the lenses when I have applied them carefully . I’ve even used a pair of loupes to look for debris on the lens and just haven’t seen it. I first started using it on our interchangeable objectives for our operating microscope and we were very cognizant of any debris falling into the wound after application, I don’t get carried away with the application and if I leave some chunks I certainly wipe them off with a paper  towel or a microfiber cloth 

On Sat, May 22, 2021 at 14:04 ROBERT WYNNE <robert-wynne@...> wrote:
I would be very suspect to use any anti-siezing compound near optics. This is due the introduction of fine metallic particles that make the compound "anti- siezing" even graphite from a "lead" pencil. Anything harder than the lens or coating used as a lubricant is potentially detrimental/destructive to the optics. -Best, Robert
On 05/22/2021 8:29 AM Jeffc <jeffcrilly@...> wrote:
 
 
I’m not familiar with metals and thread sizing except from the perspective of experiencing stuck parts.  
 
I also wonder if “anti-sieze” would be appropriate..  I feel like this would potentially get on optics near the part. 
 
https://www.westmarine.com/buy/star-brite--anti-seize-thread-lubricant--15067002

 

On May 22, 2021, at 7:48 AM, M Hambrick <mhambrick563@...> wrote:

I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike

--
TJF MOBILE


ROBERT WYNNE
 

You have me one this one. I've been involved with machine shops over the last 40 years and have never run into a situation where a hand tightened threaded assembly was so easily siezed that it could not be parted - except when a 12" diameter dowel required a soak in a furnace at 900 degrees to free it while hanging upside down over a padded platen.
 
I have a small shop and its fairly well equipped for its size but my channel locks with RTV padding wrapped around the OTA got me zilch. Even held in a "V" groove in a vise (here I had to be especially careful not to crush the OTA out of round) got me nowhere. If I had a engine lathe with a 3" collet I probably would have been able to break the seize. -Best, Robert

On 05/22/2021 7:48 AM M Hambrick <mhambrick563@...> wrote:
 
 
I know your pain Robert.

The first time I locked my ADA2767 and ADA 671 together I did not have any strap wrenches. Using extreme caution I was able to break them loose using a pair of Channellocks and a vise with lots of padding. I think that the usefulness of the strap wrench depends on what kind of rubber is used for the straps. It has to be strong, and it has to be able to grip.

I wonder what the thinking is on putting a very small amount of oil on the threads and / or mating surfaces to avoid this or to at least minimize the amount of force needed to break them loose.

Mike