Date   

Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Roland Christen
 


Someone suggested once to turn the mount upside down while inserting the counterweight shaft and let gravity pull the shaft into the threads
That is how I do it, actually.

Rolando


-----Original Message-----
From: Joel Short <buckeyestargazer@...>
To: main@ap-gto.groups.io
Sent: Tue, Aug 17, 2021 11:47 am
Subject: Re: [ap-gto] Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

On Tue, Aug 17, 2021 at 11:32 AM, Cheng-Yang Tan wrote:
The more important question, is how to not do this again.
Someone suggested once to turn the mount upside down while inserting the counterweight shaft and let gravity pull the shaft into the threads (being careful not to force anything).  I have found this to be immensely helpful advice.  For some reason when I would try to hold the counterweight shaft from below and push up it would take several tries to get it right.  Flipping the mount upside down and holding the shaft over the mount threads results in mating the parts easily, at least for me.  
joel

--
Roland Christen
Astro-Physics


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

The new CW shafts have a lead in and that really helps square it w.r.t. the adapter. I usually get it in after the first try ... which was also true for the gouging incident ...

cytan

On Tuesday, August 17, 2021, 11:47:07 AM CDT, Joel Short <buckeyestargazer@...> wrote:


On Tue, Aug 17, 2021 at 11:32 AM, Cheng-Yang Tan wrote:
The more important question, is how to not do this again.
Someone suggested once to turn the mount upside down while inserting the counterweight shaft and let gravity pull the shaft into the threads (being careful not to force anything).  I have found this to be immensely helpful advice.  For some reason when I would try to hold the counterweight shaft from below and push up it would take several tries to get it right.  Flipping the mount upside down and holding the shaft over the mount threads results in mating the parts easily, at least for me.  
joel


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Joel Short
 

On Tue, Aug 17, 2021 at 11:32 AM, Cheng-Yang Tan wrote:
The more important question, is how to not do this again.
Someone suggested once to turn the mount upside down while inserting the counterweight shaft and let gravity pull the shaft into the threads (being careful not to force anything).  I have found this to be immensely helpful advice.  For some reason when I would try to hold the counterweight shaft from below and push up it would take several tries to get it right.  Flipping the mount upside down and holding the shaft over the mount threads results in mating the parts easily, at least for me.  
joel


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

Hi Rolando,
   Believe me, I stopped once I felt it got stuck. I know enough to know when to stop :) But I guess, I wasn't fast enough ..,

   Do you think that a brass insert might actually be better rather than SS? The brass insert will just be a perishable that needs to be replaced once every few years.

cytan



On Tuesday, August 17, 2021, 11:39:42 AM CDT, Roland Christen via groups.io <chris1011@...> wrote:



The more important question, is how to not do this again.
If it doesn't thread in easily, don't force it. Unscrew it before it galls the metal and clean out whatever is causing it to not thread in.

Rolando


-----Original Message-----
From: Cheng-Yang Tan via groups.io <cytan299@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Tue, Aug 17, 2021 11:32 am
Subject: Re: [ap-gto] Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

I owe the guys doughnuts :)

I'll have to ask a real machinist to do this and that'll cost me lunch :) 

I have to get a new CW adapter anyways, so it's more cost effective to buy both directly from AP.

The more important question, is how to not do this again.

Suggestions?

cytan

On Tuesday, August 17, 2021, 11:29:09 AM CDT, Geert <geert.vandenbulcke@...> wrote:




You still have a perfectly good counterweight shaft if the machineshop cuts new thread on it, it will only be some inches shorter.

Geert

--------

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


--
Roland Christen
Astro-Physics


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Roland Christen
 


The more important question, is how to not do this again.
If it doesn't thread in easily, don't force it. Unscrew it before it galls the metal and clean out whatever is causing it to not thread in.

Rolando


-----Original Message-----
From: Cheng-Yang Tan via groups.io <cytan299@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Tue, Aug 17, 2021 11:32 am
Subject: Re: [ap-gto] Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

I owe the guys doughnuts :)

I'll have to ask a real machinist to do this and that'll cost me lunch :) 

I have to get a new CW adapter anyways, so it's more cost effective to buy both directly from AP.

The more important question, is how to not do this again.

Suggestions?

cytan

On Tuesday, August 17, 2021, 11:29:09 AM CDT, Geert <geert.vandenbulcke@...> wrote:




You still have a perfectly good counterweight shaft if the machineshop cuts new thread on it, it will only be some inches shorter.

Geert

--------

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


--
Roland Christen
Astro-Physics


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

I owe the guys doughnuts :)

I'll have to ask a real machinist to do this and that'll cost me lunch :) 

I have to get a new CW adapter anyways, so it's more cost effective to buy both directly from AP.

The more important question, is how to not do this again.

Suggestions?

cytan

On Tuesday, August 17, 2021, 11:29:09 AM CDT, Geert <geert.vandenbulcke@...> wrote:




You still have a perfectly good counterweight shaft if the machineshop cuts new thread on it, it will only be some inches shorter.

Geert

--------

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Geert
 



You still have a perfectly good counterweight shaft if the machineshop cuts new thread on it, it will only be some inches shorter.

Geert

--------


cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Joe Zeglinski
 

Hi,
 
    Here’s another suggestion, which hasn’t been suggested,  quite the same way, on getting the adapter loose enough to “torque” off the bar.
 
    Heating the mated combination or freezing the combination doesn’t seem to have much effect, since the SS materials just respond the same way, and shrink or expand together too slowly. Then they return to the same temperature even if you act quickly. But, how about “differential heating”
of the two parts ?
 
    The trick is to keep the “bar as cool as possible”, relative to the adapter's “elevated”  temperature.
Perhaps the cwt.  bar could be (safely) secured in a large vice, and just heat the adapter itself, from an air-flow directed nozzle adapter of  very hot HEAT GUN.  A hair dryer might work, set at its highest level, but not quite as effectively as the bench tool.
 
    Before inserting in the bench vice, shield the bar   nearest to the adapter, away  from the hot air stream  as best you can, perhaps even with just several wrapped layers of  fibreglass wool walll insulation. The glass  will keep the heat gun’s air stream  from hitting and warming the bar too quickly, as the “much smaller mass”  of the adapter’s threaded hole  expands “radially outward” much faster, hopefully releasing its grip on the cwt. threads.
 
    At that point - acting as quickly as you can - grip the adapter with heavy work gloves, something like  “welders gloves”, and see if it will budge.
If that still fails, devise an  “insulated lever bar” – say,  a 2-foot long  piece of 2x4 , drilled  at its length centre , with hole being slightly larger than  the cwt. threads diameter. Slip it over the end of the bar and bolt the 2x4  to the adapter’s two  holes,  one above and below the adapter ring centre.
 
    Finally, you can slam the 2x4  at its top end, with a sledge hammer, giving  that added levered torque the 2x4 extension provides to the adapter, to break the thread’s bind. The 2x4 being wood, won’t affect the continual heat being delivered  to the adapter ring’s  “opposite face” side, so the adapter  continues to expand, while the heat “isolated”  cwt. bar still remains relatively cooler, for a while.
 
    If it doesn’t break the seal with repeated strikes the first time, have a bucket of ice-water handy, to pour ONLY  over the bar’s far end itself, and give the 2x4 lever another slam, since the ice water should then have even shrunk the bar diameter somewhat, while the adapter is still quite hot, and its centre diameter still  expanding from the continual  heat gun air stream.
 
    I think that the triple combination of the  “differential heating” of the adapter outer area,  with something like a 1,200 watt heat gun, while additionally super cooling the bar “nearby ” (but not on), the adapter, should respond well, to a strong slam at the extreme end of the 2x4 lever arm -  with say a 5 lb. sledge  hammer.
 
    Desperate times ... call for desperate measures !
 
Joe Z.


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 



On Tuesday, August 17, 2021, 11:12:54 AM CDT, Seb@stro <sebastiendore1@...> wrote:


Well, its unfortunate that you were enable to save any parts from this endeavor, cytan. 

It's part of the hobby, I guess :) I ordered a new CW shaft and CW adapter just now. AP is checking whether they have spare sleeves, I'd get one as well. Right now, I have a CW adapter without a sleeve which is rather useless.

The good thing is that I have a spare CW adapter and CW shaft, so I'm actually ok.

It never happened to me and I am not mechanically savy either, but I wonder if putting anything at all on the threads is a good idea... I would think any sticky/oily substance makes particulates stick and accumulate over time much faster on the threaded parts, which kind of defeat the reason of putting the antiseize in the first place... My thinking may be wrong and I shall stand corrected, but I always thought of using anti-seize stuff only when there is a risk of oxydation/corrosion on the metal mating parts (which is less likely with SS).

The graphite lubricant I used is dry, so it's not sticky after application. The guys did suggest using anti-seize because they use it all the time on their SS bolts and nuts. But it's a messy lube.

cytan



I wonder if a simple toothbrush/dry cloth cleaning before threading the shaft is enough in our use case ? 

Sébastien


De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Cheng-Yang Tan via groups.io <cytan299@...>
Envoyé : 17 août 2021 11:25
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve
 
Well, the guys got it off by milling the sleeve so that it is thin enough to untwist the sleeve from the shaft. 

Once the sleeve is off, you can see that the threads on the CW shaft are gouged:

Inline image


I had used this spray on the threads to hopefully prevent this problem:



Maybe that's not the type of lube that I should use?

Speaking as a non-mechanical person:

Since both the sleeve and the CW are made of stainless steel (I checked that the sleeve is SS with a magnet), I think there's always a danger of SS on SS gouging. I'm wondering whether the sleeve can be made of brass which is self-lubricating?

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Seb@stro
 

Well, its unfortunate that you were enable to save any parts from this endeavor, cytan. 

It never happened to me and I am not mechanically savy either, but I wonder if putting anything at all on the threads is a good idea... I would think any sticky/oily substance makes particulates stick and accumulate over time much faster on the threaded parts, which kind of defeat the reason of putting the antiseize in the first place... My thinking may be wrong and I shall stand corrected, but I always thought of using anti-seize stuff only when there is a risk of oxydation/corrosion on the metal mating parts (which is less likely with SS).

I wonder if a simple toothbrush/dry cloth cleaning before threading the shaft is enough in our use case ? 

Sébastien


De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Cheng-Yang Tan via groups.io <cytan299@...>
Envoyé : 17 août 2021 11:25
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve
 
Well, the guys got it off by milling the sleeve so that it is thin enough to untwist the sleeve from the shaft. 

Once the sleeve is off, you can see that the threads on the CW shaft are gouged:

Inline image


I had used this spray on the threads to hopefully prevent this problem:



Maybe that's not the type of lube that I should use?

Speaking as a non-mechanical person:

Since both the sleeve and the CW are made of stainless steel (I checked that the sleeve is SS with a magnet), I think there's always a danger of SS on SS gouging. I'm wondering whether the sleeve can be made of brass which is self-lubricating?

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

Well, the guys got it off by milling the sleeve so that it is thin enough to untwist the sleeve from the shaft. 

Once the sleeve is off, you can see that the threads on the CW shaft are gouged:

Inline image


I had used this spray on the threads to hopefully prevent this problem:



Maybe that's not the type of lube that I should use?

Speaking as a non-mechanical person:

Since both the sleeve and the CW are made of stainless steel (I checked that the sleeve is SS with a magnet), I think there's always a danger of SS on SS gouging. I'm wondering whether the sleeve can be made of brass which is self-lubricating?

cytan

P.S. I'll be ordering a new CW shaft + adapter today ...






On Tuesday, August 17, 2021, 10:09:57 AM CDT, J. Belden via groups.io <jjb4469@...> wrote:


I personally use a little never seize on parts that I don’t want to seize up

Joe






Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

J. Belden
 

I personally use a little never seize on parts that I don’t want to seize up

Joe


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

J. Belden
 

I had an extremely difficult time getting three extension parts apart(Nightcrawler extensions) but heating, cooling, swearing, strap wrenches, lubricants and etc did not budge. So, I ended up having to dremel cut one of the extension tubes to save the other two, so I know it seems like an over engineered effort but sometimes it just happens. Though, these three parts were AL but SS can be a pain as well when it gets galled.

Joe

Good luck


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Klwalsh2061
 

Odd size nuts? Maybe so. 

Try McMaster-Carr. They carry an extremely wide selection of hardware, including large SAE and Metric nuts and bolts. 


Re: AP V2 driver, move axis command help.

Andy Ermolli
 

So clearly I am losing my mind as sorta remembered buying a V chip, I looked in my desk drawer and sure enough it was a V2.
I just installed it in the Mach1 and I can confirm that the 4°/s move axis rate works as expected.


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

Hi Chris,

The two people working on it have at least 60 to 70 years of working with SS between them.

They first started with what you described. Strapping wrench and vice and nothing moved. 

Then the effort escalated.

Believe you me, I didn't ask novices to work on this.

cytan



On Monday, August 16, 2021, 10:26:15 AM CDT, Christopher Erickson <christopher.k.erickson@...> wrote:


Good grief people.

The counterweight shaft and adapter are stuck together because one or more slivers of aluminum are caught in the threads. The slivers of aluminum came from the old aluminum threaded hole on the original mount counterweight shaft adapter. Aluminum is softer than the stainless steel parts. A vise with wood jaws and a rubber strap wrench will get them apart.

Any competent machine shop can get them apart for you in 3 minutes.

No need to over-think this or over-engineer a solution.

As Roland might say, no need to hunt a red herring down a blind alley with a Howitzer.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Mon, Aug 16, 2021, 5:11 AM Cheng-Yang Tan via groups.io <cytan299=yahoo.com@groups.io> wrote:
Unfortunately, it's really, really stuck.

I asked two of my colleagues who are senior techs to help remove the sleeve. These guys work on stainless steel threaded parts all the time and they can't get it off with a blow torch (well, there goes the mica washer) + wrench + elbow grease. It's going on a lathe next to shave off the sleeve.

And about using nuts, they think it's an oddball size so there's no nuts that can fit.

At this point, it's just a point of pride for them to get the sleeve off. But their advice is to get a new CW. Who knows why the CW got stuck in the first place -- it may be a nick on one of the threads or I'm a lot stronger than I think I am :)

I had sprayed on graphite lube on the CW threads before, but clearly that wasn't enough to prevent this.

cytan

On Monday, August 16, 2021, 10:01:33 AM CDT, KLWALSH2061 <kevin.walsh@...> wrote:


If you can get two nuts of the proper size, screw them on to the thread size adapter, then tighten them against each other.
Then use a pair of wrenches, one on the shaft and one on the inner nut. The outer nut will act as a stop for the inner nut, allowing the adapter to be unscrewed from the end of the shaft. Once the adapter is off, you can use the two wrenches to loosen the two nuts and remove them from the adapter.

Good luck.
KWalsh


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Christopher Erickson
 

Good grief people.

The counterweight shaft and adapter are stuck together because one or more slivers of aluminum are caught in the threads. The slivers of aluminum came from the old aluminum threaded hole on the original mount counterweight shaft adapter. Aluminum is softer than the stainless steel parts. A vise with wood jaws and a rubber strap wrench will get them apart.

Any competent machine shop can get them apart for you in 3 minutes.

No need to over-think this or over-engineer a solution.

As Roland might say, no need to hunt a red herring down a blind alley with a Howitzer.

-Christopher Erickson
Observatory engineer
Waikoloa, HI 96738
www.summitkinetics.com
   

On Mon, Aug 16, 2021, 5:11 AM Cheng-Yang Tan via groups.io <cytan299=yahoo.com@groups.io> wrote:
Unfortunately, it's really, really stuck.

I asked two of my colleagues who are senior techs to help remove the sleeve. These guys work on stainless steel threaded parts all the time and they can't get it off with a blow torch (well, there goes the mica washer) + wrench + elbow grease. It's going on a lathe next to shave off the sleeve.

And about using nuts, they think it's an oddball size so there's no nuts that can fit.

At this point, it's just a point of pride for them to get the sleeve off. But their advice is to get a new CW. Who knows why the CW got stuck in the first place -- it may be a nick on one of the threads or I'm a lot stronger than I think I am :)

I had sprayed on graphite lube on the CW threads before, but clearly that wasn't enough to prevent this.

cytan

On Monday, August 16, 2021, 10:01:33 AM CDT, KLWALSH2061 <kevin.walsh@...> wrote:


If you can get two nuts of the proper size, screw them on to the thread size adapter, then tighten them against each other.
Then use a pair of wrenches, one on the shaft and one on the inner nut. The outer nut will act as a stop for the inner nut, allowing the adapter to be unscrewed from the end of the shaft. Once the adapter is off, you can use the two wrenches to loosen the two nuts and remove them from the adapter.

Good luck.
KWalsh


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Cheng-Yang Tan
 

Unfortunately, it's really, really stuck.

I asked two of my colleagues who are senior techs to help remove the sleeve. These guys work on stainless steel threaded parts all the time and they can't get it off with a blow torch (well, there goes the mica washer) + wrench + elbow grease. It's going on a lathe next to shave off the sleeve.

And about using nuts, they think it's an oddball size so there's no nuts that can fit.

At this point, it's just a point of pride for them to get the sleeve off. But their advice is to get a new CW. Who knows why the CW got stuck in the first place -- it may be a nick on one of the threads or I'm a lot stronger than I think I am :)

I had sprayed on graphite lube on the CW threads before, but clearly that wasn't enough to prevent this.

cytan

On Monday, August 16, 2021, 10:01:33 AM CDT, KLWALSH2061 <kevin.walsh@...> wrote:


If you can get two nuts of the proper size, screw them on to the thread size adapter, then tighten them against each other.
Then use a pair of wrenches, one on the shaft and one on the inner nut. The outer nut will act as a stop for the inner nut, allowing the adapter to be unscrewed from the end of the shaft. Once the adapter is off, you can use the two wrenches to loosen the two nuts and remove them from the adapter.

Good luck.
KWalsh


Re: Ugghhh cross threaded CW shaft into CW shaft adapter with metal threaded sleeve

Klwalsh2061
 

If you can get two nuts of the proper size, screw them on to the thread size adapter, then tighten them against each other.
Then use a pair of wrenches, one on the shaft and one on the inner nut. The outer nut will act as a stop for the inner nut, allowing the adapter to be unscrewed from the end of the shaft. Once the adapter is off, you can use the two wrenches to loosen the two nuts and remove them from the adapter.

Good luck.
KWalsh


Re: AP V2 driver, move axis command help.

Andy Ermolli
 

Also I can’t believe that I was off by a full 0.00001x in my estimation of the move rate.

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