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Richard Wasserman
26-Jun-2012, 10:13
I am doing a CLA on a Sinar Norma following Philip Morgan's excellent directions and Video and have run into a problem. I can't remove the fine focus assembly from the monorail sleeve. This is a steel part in a snug aluminum hole and I assume that after 50 years it has seized and won't budge. I have been soaking it in PB Blaster for 24 hours, and have tried heating it with a butane torch. I have also liberally applied swearing—all to no avail. Before I resort to explosives is there anything else I can try?

lenser
26-Jun-2012, 10:20
Knowing nothing about the relative expansion and shrinkage of metals, I'm admittedly going way out on a limb here, but two ideas come to mind.

First, try putting it in a freezer for a few hours in case they shrink at different rates which may allow them to free up. Secondly, instead of just a localized heating with a blow torch, if the assembly is in an all metal unit that won't be harmed or warped by heating, try the entire unit in your kitchen oven at a moderate heat level. It may be that just the local heating isn't working because the expansion is being limited by the larger surrounding mass of the outer unit not being heated on an wide enough front.

E. von Hoegh
26-Jun-2012, 10:34
Aluminium expands roughly twice as much as steel for a given increase of temperature. That means if it is a steel shaft in an aluminium housing, heat is your friend. For, say, an aluminium plug in a steel part, you want to cool it. If it has corroded or galled, you may have a problem. Let it soak as long as you can. Gentle warming and cooling will help to draw the penetrant in, possibly loosening the parts. Be patient - almost everything will come apart if you are patient and don't hammer on it.

Vick Ko
26-Jun-2012, 10:40
Yes, aluminum would also expand more than steel, so if the shaft is steel, and the collar (i.e. hole) is aluminum, heating should work. But if it is corroded, well, that's like saying that it is chemically glued onto the shaft.

Maybe try thermally cycling the parts.

Maybe when the parts are hot, try tapping the sleeve.

Maybe make another part with a hole that butts up against the collar/sleeve to aid with tapping.

Good luck

Scott Walker
26-Jun-2012, 10:43
Put it in liquid propane for a few minutes. Once you remove it from the propane you should be able to tap the center out after a few minutes as the aluminum warms up and expands at a much greater rate than the steel.

Richard Wasserman
26-Jun-2012, 10:48
Interesting—where do I get liquid propane? Propane torch cylinder maybe?


Put it in liquid propane for a few minutes. Once you remove it from the propane you should be able to tap the center out after a few minutes as the aluminum warms up and expands at a much greater rate than the steel.

Nathan Potter
26-Jun-2012, 10:52
I am doing a CLA on a Sinar Norma following Philip Morgan's excellent directions and Video and have run into a problem. I can't remove the fine focus assembly from the monorail sleeve. This is a steel part in a snug aluminum hole and I assume that after 50 years it has seized and won't budge. I have been soaking it in PB Blaster for 24 hours, and have tried heating it with a butane torch. I have also liberally applied swearing—all to no avail. Before I resort to explosives is there anything else I can try?

In the case of a steel part in an aluminum hole the TCE (Thermal Expansion Coefficient) difference goes the wrong way for heating. Aluminum is typically 20 to 24X10^-6 whereas iron/steel may be down around 7 to 14X10^-6 about a factor of three different. Since the aluminum expands greater per degree C one would normally try to cool the combination hoping the aluminum hole would open up slightly while the steel expands less slightly. So a freezer might work but a liquid nitrogen dunk (I think about 77 K) would be better. This assumes that the joining was originally just a press fit (poor design for dis-similar materials. If an adhesive was originally used the cooling might actually rupture the bond, even if very sturdy epoxy, so the release can be made.

Nate Potter, Austin TX.

Yes the hole gets smaller so heat is needed. Ignore my stupidity.

E. von Hoegh
26-Jun-2012, 10:58
Interesting—where do I get liquid propane? Propane torch cylinder maybe?

Your freezer and boiling water will work just fine.

Scott Walker
26-Jun-2012, 11:02
Interesting—where do I get liquid propane? Propane torch cylinder maybe?

It depends on your laws, the old propane tanks had no tip protection so they would release the liquid by turning them upside down and opening the valve and literally pouring the liquid into a plastic pail.
It is more complicated to get liquid out with the new tanks but still doable, and certainly with the small torch tanks.
I keep an old 20 lb bbq tank for such purposes and know someone that will refill it, as it is not really legal to fill the old ones here.

I would recomend doing this outdoors, and remember propane gas is heavy and can linger for many hours in the right conditions.

Richard Wasserman
26-Jun-2012, 11:02
The steel part is supposed to be a slip fit held in place by a set-screw—no press fit or adhesive which I suppose is in my favor. Where am I supposed to find things like liquid propane and nitrogen? I don't think my neighborhood hardware store is going to have them...



In the case of a steel part in an aluminum hole the TCE (Thermal Expansion Coefficient) difference goes the wrong way for heating. Aluminum is typically 20 to 24X10^-6 whereas iron/steel may be down around 7 to 14X10^-6 about a factor of three different. Since the aluminum expands greater per degree C one would normally try to cool the combination hoping the aluminum hole would open up slightly while the steel expands less slightly. So a freezer might work but a liquid nitrogen dunk (I think about 77 K) would be better. This assumes that the joining was originally just a press fit (poor design for dis-similar materials. If an adhesive was originally used the cooling might actually rupture the bond, even if very sturdy epoxy, so the release can be made.

Nate Potter, Austin TX.

Yes the hole gets smaller so heat is needed. Ignore my stupidity.

Richard Wasserman
26-Jun-2012, 11:07
I like this low tech idea. Does it matter which I do first? I'm thinking freezer, then boiling water.



Your freezer and boiling water will work just fine.

E. von Hoegh
26-Jun-2012, 11:08
The steel part is supposed to be a slip fit held in place by a set-screw—no press fit or adhesive which I suppose is in my favor. Where am I supposed to find things like liquid propane and nitrogen? I don't think my neighborhood hardware store is going to have them...

Just be patient. Let it soak in penetrant. Put it in the freezer overnight, then drop it in boiling water next morning. You'll get a wider temperature range that way than with liguid propane, and you won't blow yourself up either. Keep it simple. Be patient.

Jerry Bodine
26-Jun-2012, 11:17
Have you considered a PM to Philip Morgan (philipmorg)?

Richard Wasserman
26-Jun-2012, 11:22
I'll try that, thanks! I really don't want to blow up if I can avoid it.




Just be patient. Let it soak in penetrant. Put it in the freezer overnight, then drop it in boiling water next morning. You'll get a wider range that way than with liguid propane, and you won't blow yourself up either. Keep it simple. Be patient.

Richard Wasserman
26-Jun-2012, 11:23
I did contact him, but the techniques he suggested didn't work. I think my particular camera must be really stuck.


Have you considered a PM to Phillip Morgan?

Steve Goldstein
26-Jun-2012, 11:29
Rumor has it that an even better penetrant than PB Blaster is a 50:50 mixture of acetone and ATF (automatic transmission fluid). I haven't had the opportunity to try it myself but know some car mechanics who really like it. Acetone is flammable and moderately nasty, so I wouldn't use this indoors without significant ventilation.

Richard Wasserman
26-Jun-2012, 11:35
I'll keep that i mind, thanks. I bet it smells better (or at least less) too—PB Blaster really stinks!



Rumor has it that an even better penetrant than PB Blaster is a 50:50 mixture of acetone and ATF (automatic transmission fluid). I haven't had the opportunity to try it myself but know some car mechanics who really like it. Acetone is flammable and moderately nasty, so I wouldn't use this indoors without significant ventilation.

E. von Hoegh
26-Jun-2012, 11:36
Rumor has it that an even better penetrant than PB Blaster is a 50:50 mixture of acetone and ATF (automatic transmission fluid). I haven't had the opportunity to try it myself but know some car mechanics who really like it. Acetone is flammable and moderately nasty, so I wouldn't use this indoors without significant ventilation.

The only better penetrant than PB Blaster is Kroil. If you are patient, kerosene is good enough. If you are not patient, nothing works.

domaz
26-Jun-2012, 12:01
This problem sounds remarkably (or not) similar to the common problem in older bikes of the aluminum stem getting stuck in the steel steerer tube of the frame. Google on that issue and you will find all kinds of tips. Boiling water is supposed to be fairly effective, I have an old bike with a stuck stem expander bolt I'm going to try that trick on soon..

Scott Walker
26-Jun-2012, 12:25
I'll try that, thanks! I really don't want to blow up if I can avoid it.

Blowing up is seldom good unless you are a cartoon. :rolleyes:
Being a mechanic by trade, (no longer working as one) and living on a farm has given me the opportunity to be forced to remove all kinds of stuck parts, and liquid propane has been a staple for many years.
I like the idea of the freezer and boiling water, it might just work.
The problem and solution are fairly simple, use temperature and expansion rates of dissimilar metals to increase the gap between them and allow them to move freely, unfortunately implementing of the solution is not always as simple as the solution itself.
You most likely have a small amount of galvanic corrosion that is not allowing the parts to be separated. Penetrating oils will help but by far the most effective method is to make the inside part smaller or the outside part bigger.

E. von Hoegh
26-Jun-2012, 12:28
This problem sounds remarkably (or not) similar to the common problem in older bikes of the aluminum stem getting stuck in the steel steerer tube of the frame. Google on that issue and you will find all kinds of tips. Boiling water is supposed to be fairly effective, I have an old bike with a stuck stem expander bolt I'm going to try that trick on soon..

Good luck. I bought an old Raleigh T531 frame with a stuck seat post. Tried everything, including turning an arbor to attach a chain to the bottom bracket and a come-a-long between two trees. I eventually cut the top off the Campagnolo post and chiseled a groove down the inside, twisting it with a pipe wrench finally loosened it.

jp
26-Jun-2012, 12:35
An alternative to propane would be a can of refrigerant from the auto parts store. Some of the canned air dusting products may be propane as well, and liquid comes out if you use them upside down.

rdenney
26-Jun-2012, 12:52
An alternative to propane would be a can of refrigerant from the auto parts store. Some of the canned air dusting products may be propane as well, and liquid comes out if you use them upside down.

It's against the law to do that with refrigerant. But propane makes a better refrigerant than those refrigerants, so just take a propane torch and hold it upside-down and then open the valve.

Put the cigarette out first, though.

Rick "who uses propane refrigerant in his old motorhome dash air conditioning" Denney

dsphotog
26-Jun-2012, 14:00
If it's working, I'd leave that part alone.
What's that old saying?
If it jams, force it.
If it breaks, it needed replacing anyway.

Richard Wasserman
26-Jun-2012, 14:41
Unfortunately it's a part that needs adjusting, and in order to adjust it I first need to remove it. It's currently in the freezer getting ready for its hot water bath.



If it's working, I'd leave that part alone.
What's that old saying?
If it jams, force it.
If it breaks, it needed replacing anyway.

dsphotog
26-Jun-2012, 14:53
Keep us posted...
I like soaking parts in Marvel Mystery oil.

Gary Beasley
26-Jun-2012, 14:59
I've dealt with steel shafts stuck in aluminum before on a larger scale and eventually had to use vinegar to dissolve the corrosion before I could get it loose. After that a good flush with oil to displace the vinegar and I was back in business. No idea if it would work on your part.

Michael Jones
27-Jun-2012, 07:38
I vote for the liquid propane only because the 4th of July is coming. Please videotape & tape the result... :)

Mike

Richard Wasserman
27-Jun-2012, 07:57
A bit like the guys who lit their barbeque with an assist from liquid oxygen, perhaps?



I vote for the liquid propane only because the 4th of July is coming. Please videotape & tape the result... :)

Mike

Preston
27-Jun-2012, 08:38
I would not use propane or any other liquified flammable gas. These materials have very wide explosive ranges and very high expansion ratios, e.g. Propane is 1860:1. Never use liquid oxygen! If it comes in contact with any grease or oil, a flash fire will result! If you do use a liquified gas, I would suggest carbon dioxide. Use it in a well ventilated area. Be sure to use eye protection and suitable gloves.

--P

Richard Wasserman
27-Jun-2012, 08:48
Don't worry, I share your enthusiasm for flammable gasses and I'm staying away from them. I have tried a couple of freezing/boiling water cycles, which had no effect. I currently have the parts soaking in PB Blaster and I'm thinking of giving a vinegar soak a try.
I hope that something will eventually work, if I can be patient enough.



I would not use propane or any other liquified flammable gas. These materials have very wide explosive ranges and very high expansion ratios, e.g. Propane is 1860:1. Never use liquid oxygen! If it comes in contact with any grease or oil, a flash fire will result! If you do use a liquified gas, I would suggest carbon dioxide. Use it in a well ventilated area. Be sure to use eye protection and suitable gloves.

--P

E. von Hoegh
27-Jun-2012, 09:24
Don't worry, I share your enthusiasm for flammable gasses and I'm staying away from them. I have tried a couple of freezing/boiling water cycles, which had no effect. I currently have the parts soaking in PB Blaster and I'm thinking of giving a vinegar soak a try.
I hope that something will eventually work, if I can be patient enough.


If you soak it in vinegar, it likely won't have much effect due to the oil that's already there. Try baking it at about 250f, then dropping it back in the PB Blaster. As it cools, the oil will be drawn into any (now larger due to heat) crevices.

I cannot stress enough how important patience is.

E. von Hoegh
30-Jun-2012, 08:10
Well?

Richard Wasserman
30-Jun-2012, 08:30
Thanks for asking! The part is currently soaking in Kroil. I put it in the oven to warm up before its bath, but so far it shows no signs of movement. I periodically look at it and tap on it—more I think to make me feel like I'm contributing to the process than anything else. You counseled patience and I'm doing my best....

Any other ideas?


Well?

E. von Hoegh
30-Jun-2012, 09:19
Thanks for asking! The part is currently soaking in Kroil. I put it in the oven to warm up before its bath, but so far it shows no signs of movement. I periodically look at it and tap on it—more I think to make me feel like I'm contributing to the process than anything else. You counseled patience and I'm doing my best....

Any other ideas?

If I had the part, or could see it, I might have some ideas. Kroil is the best penetrant available, and thermal cycling is good, too.

If you have an ultrasonic, even a small jewelry cleaner, put it in there in Kroil and give it a blast, as long as the cleaner will tolerate.

awldune
5-Jul-2012, 18:33
If you could share a picture that would be helpful for troubleshooting.

Richard Wasserman
6-Jul-2012, 09:06
Her's a photo as requested. I have ordered an ultrasonic cleaner which will arrive early next week. I am starting to lose hope of ever getting this apart.

E. von Hoegh
6-Jul-2012, 09:09
I see a flat. Are there two flats? Have you tried to unscrew it from the housing? What does the service literature say? It appears that the housing and shaft screw into the aluminium; when the part has been screwed in and the gear adjusted to be central over the rack, the set screw is tightened.

Richard Wasserman
6-Jul-2012, 09:26
There are 2 flats, but the shaft is not threaded, but is an eccentric cam. The shaft is supposed to turn and adjust the placement of the gear (pinion) which mates with the focus rack on the monorail.



I see a flat. Are there two flats? Have you tried to unscrew it from the housing? What does the service literature say? It appears that the housing and shaft screw into the aluminium; when the part has been screwed in and the gear adjusted to be central over the rack, the set screw is tightened.

E. von Hoegh
6-Jul-2012, 09:50
Have you tried twisting it?

Richard Wasserman
6-Jul-2012, 10:12
Yes, but it won't budge



Have you tried twisting it?

Colin Graham
6-Jul-2012, 10:50
You've probably seen this video (from your picture it looks like you already removed the rail bushing to access the hidden set-screw) but thought I'd post it just in case. You only mentioned a single set screw in an earlier post, there are two securing the stem assembly.


http://sinarnormaclavideoguide.s3.amazonaws.com/7-Final-CleanBottomsideAssembly-960px.mp4

If they have both been removed, I wonder if a gear puller could be rigged to work?

E. von Hoegh
6-Jul-2012, 11:13
Yes, but it won't budge
Have you tried while it is hot? Of course all the caveats about a properly fitting wrench apply here.....

Richard Wasserman
24-Jul-2012, 13:44
I'm making progress! After many days of soaking in Kroil the shaft can now be moved a bit—it can be rotated back and forth about 10 degrees or so. I still can't remove it, because it is very tight, but I'm encouraged. I'm thinking of freezing the assembly and then gently heating the aluminum to expand it. Any thoughts?

E. von Hoegh
24-Jul-2012, 14:01
I'm making progress! After many days of soaking in Kroil the shaft can now be moved a bit—it can be rotated back and forth about 10 degrees or so. I still can't remove it, because it is very tight, but I'm encouraged. I'm thinking of freezing the assembly and then gently heating the aluminum to expand it. Any thoughts? The steel and aluminium will always be about the same temp, because of the contact. Heating it will help; you've already succeeded.

Patience, thermal cycling, patience, wiggling, patience,....... But you got it free!

I used to work with an old guy; we dragged Model T and Model A running gears out of barns, out from behind barns, dug them up - literally- to restore and sell at Hershey. He was a real mechanic, and would spend weeks freeing rusted bits with heat, oil, light tapping, and lots of patience. He used furnace oil as a penetrant, and it works. We'd never heard of Kroil in 1978.

Richard Wasserman
24-Jul-2012, 14:05
That's not the answer I was looking for. You were supposed to say "Great idea—the shaft will pop right out!" I guess I'll keep on trying everything I can think of.....



The steel and aluminium will always be about the same temp, because of the contact. Heating it will help; you've already succeeded.

Patience, thermal cycling, patience, wiggling, patience,....... But you got it free!

I used to work with an old guy; we dragged Model T and Model A running gears out of barns, out from behind barns, dug them up - literally- to restore and sell at Hershey. He was a real mechanic, and would spend weeks freeing rusted bits with heat, oil, light tapping, and lots of patience. He used furnace oil as a penetrant, and it works. We'd never heard of Kroil in 1978.

E. von Hoegh
24-Jul-2012, 14:11
Great idea!! The shaft will pop right out!































































































































Eventually.

Jim Michael
24-Jul-2012, 14:25
If you need an extra low temperature soak you can bust up dry ice and add to acetone and then soak the parts you are trying to separate in that. Also possibly differential heating and cooling if the inner part can be cooled while outer part heated.

E. von Hoegh
24-Jul-2012, 14:47
I just thought of something... are you sure there isn't still a setscrew holding it? I've seen two setscrews used, one to lock a piece and a second to lock the setscrew. One on top of the other.

Harold_4074
24-Jul-2012, 14:56
It sounds like you have either galling (transfer of aluminum to the steel) or corrosion of the aluminum. In either case, you will probably need to exert some longitudinal force while you twist, or you will eventually have a freely rotating but non-removable part. If it is galling, rotating the shaft will eventually create a groove in the aluminum, and when you finally extract the shaft there will be considerable damage to the hole, possibly preventing you from reusing aluminum part.

It is sometimes possible to use a bench vise, C-clamp, or large Vise-Grip pliers to press out a small shaft. An appropriately sized wrench socket, or even a stack of washers, may allow you to support the outer part as you apply force to the shaft. Of course, an arbor press is even better, under the hands of an appropriately skilled craftsman. (You probably want to avoid hydraulic presses, as one would have to proceed with the utmost delicacy, and this is not what those machines were really designed for.)

In any case, I suggest that you give some thought to pushing or pulling shaft straight out; if the problem is galling or a burr due to a setscrew tip, a single groove parallel to the shaft will be less problematic in the long run than an oversized hole would be.

Good luck!

Richard Wasserman
24-Jul-2012, 16:23
This just keeps getting more and more interesting. What you say makes sense to me, but I'm at a bit of a loss as to how to proceed. I need to pull the shaft out of the aluminum part, and I don't know how to do that without damaging it. I wish it was as simple as squeezing it in a press, but I need to go the other way.



It sounds like you have either galling (transfer of aluminum to the steel) or corrosion of the aluminum. In either case, you will probably need to exert some longitudinal force while you twist, or you will eventually have a freely rotating but non-removable part. If it is galling, rotating the shaft will eventually create a groove in the aluminum, and when you finally extract the shaft there will be considerable damage to the hole, possibly preventing you from reusing aluminum part.

It is sometimes possible to use a bench vise, C-clamp, or large Vise-Grip pliers to press out a small shaft. An appropriately sized wrench socket, or even a stack of washers, may allow you to support the outer part as you apply force to the shaft. Of course, an arbor press is even better, under the hands of an appropriately skilled craftsman. (You probably want to avoid hydraulic presses, as one would have to proceed with the utmost delicacy, and this is not what those machines were really designed for.)

In any case, I suggest that you give some thought to pushing or pulling shaft straight out; if the problem is galling or a burr due to a setscrew tip, a single groove parallel to the shaft will be less problematic in the long run than an oversized hole would be.

Good luck!

Richard Wasserman
24-Jul-2012, 16:25
I've checked obsessively for setscrews and they have been removed. Good idea though!





I just thought of something... are you sure there isn't still a setscrew holding it? I've seen two setscrews used, one to lock a piece and a second to lock the setscrew. One on top of the other.

gustavus
24-Jul-2012, 17:22
Ultrasonic cleaner will loosen those parts.

Ivan J. Eberle
24-Jul-2012, 17:43
I'm guessing it's galled and needs pressed out. You may not incur as much damage doing that as endlessly rocking back and forth if you've got galling (essentially mechanically transferred metal--the aluminum-- onto the steel shaft). At least you're not needing to seal it hydraulically when it goes back together. If the aluminum is badly scored or corroded and the piece is big enough it may be possible to have a machine shop ream and/or hone it oversize for pressing in a brass or bronze bushing. I had a Norma and expect that there's enough aluminum in that piece that this would be the worst case.

Harold_4074
24-Jul-2012, 18:03
Ah. I had overlooked the post with the photo.

It appears that you have a steel shaft (with the pinion on the end inside the housing) which runs in an eccentric carrier, thereby allowing you to adjust the engagement depth of the pinion with the rack. From the discussion to date, it sounds like the steel shaft is seized in the carrier, but your statement that you need to pull it out rather than push it suggests that it is the carrier which is stuck in the housing. It looks very much like the carrier is aluminum, and aluminum on aluminum is one of the worst combinations for galling.

If the the steel shaft (with the drive pinion) turns freely, and it is the carrier which is stuck, you might be able to use the collet threads (the ones which allow you to squeeze down the carrier onto the shaft) to pull the carrier out of the housing. Any appropriate spacer will do, and if the bearing surface on the carrier is not sufficiently parallel to the back of whatever you screw onto the threads you may be able to heavily wax the housing and then use something like J-B Weld to create a (removable!) seating surface. If you are lucky, the designer was smart enough to use something other than aluminum for the female threads, but in any event you should use a good anti-seize on them before trying this.

Since the carrier doesn't rotate in the housing except for adjustment, I really suspect that it has either a burr from the tip of the setscrew or a very short primary setscrew still hiding at the bottom of the hole. In either case, trying to force penetrating oil through the setscrew hole and out along the shaft would be revealing.

In the worst case, you will likely either have a machinist provide you with a pull-type collet so that you can use a slide hammer to yank the assembly apart, or he will drill a hole through the opposite side of the housing, in line with the shaft, to permit it to be punched out. Because the eccentric controls the rack and pinion engagement, you really don't want any play there, and continuing to work the parts around is very likely to create some :(

E. von Hoegh
25-Jul-2012, 06:55
Ultrasonic cleaner will loosen those parts.

Read the thread.

gustavus
25-Jul-2012, 07:33
Read the thread.

When aluminum and iron come into contact, electrolysis takes place a white oxide powder is formed. An ultrasonic cleaner would have worked the oxides out freeing the parts.

By soaking the parts there is the possibility of the aluminum oxide expanding enough the break or crack the aluminum part.

When dissimilar metals are in contact with one another in the presence of an electrolyte, galvanic action occurs, resulting in the deterioration of the metal with the lower galvanic number. The electrolyte may be rain water running from one surface to another, or moisture from the air containing enough acid to cause it to act as an electrolyte.

E. von Hoegh
25-Jul-2012, 07:35
I'm guessing it's galled and needs pressed out. You may not incur as much damage doing that as endlessly rocking back and forth if you've got galling (essentially mechanically transferred metal--the aluminum-- onto the steel shaft). At least you're not needing to seal it hydraulically when it goes back together. If the aluminum is badly scored or corroded and the piece is big enough it may be possible to have a machine shop ream and/or hone it oversize for pressing in a brass or bronze bushing. I had a Norma and expect that there's enough aluminum in that piece that this would be the worst case.

It's hard to say for sure about galling. Definitely a possibility, but soaking and thermal cycling won't worsen that. If I could just get it in my hands for 30 seconds, I'd know what was going on.

E. von Hoegh
25-Jul-2012, 07:36
When aluminum and iron come into contact, electrolysis takes place a white oxide powder is formed. An ultrasonic cleaner would have worked the oxides out freeing the parts.

When dissimilar metals are in contact with one another in the presence of an electrolyte, galvanic action occurs, resulting in the deterioration of the metal with the lower galvanic number. The electrolyte may be rain water running from one surface to another, or moisture from the air containing enough acid to cause it to act as an electrolyte.

Read the thread. He's had it in an ultrasonic. More cannot hurt, though, especially now that it's moving a bit.

gustavus
25-Jul-2012, 07:39
Read the thread. He's had it in an ultrasonic. More cannot hurt, though, especially now that it's moving a bit.

You have my humble apologies.

E. von Hoegh
25-Jul-2012, 07:40
You have my humble apologies.

No worries. (smiling smiley)

Harold_4074
6-Aug-2012, 12:22
Hmmm.....did this problem ever get solved, and if so, how?

(The solution might be useful to someone else, someday.)

Richard Wasserman
6-Aug-2012, 12:58
The problem was solved, but not by me. I was totally unable to do it myself. Luckily for me a retired master machinist volunteered his services. He not only took apart the seized components, but adjusted and made everything right—some things he made more than right, by improving on the original design. I'm incredibly lucky and grateful.




Hmmm.....did this problem ever get solved, and if so, how?

(The solution might be useful to someone else, someday.)

E. von Hoegh
6-Aug-2012, 13:09
The problem was solved, but not by me. I was totally unable to do it myself. Luckily for me a retired master machinist volunteered his services. He not only took apart the seized components, but adjusted and made everything right—some things he made more than right, by improving on the original design. I'm incredibly lucky and grateful.

I assume he didn't dissolve away the aluminium with sodium hydroxide. What did he do?

Richard Wasserman
6-Aug-2012, 13:28
By the time I sent it to him the part was moving slightly. It turned out that in addition to being seized, it was galled from a set-screw, which prevented me from pulling it apart. I'm not sure what he used (I'm sure no sodium hydroxide!), but he put it in a machine and was able to easily separate the stuck parts. He then machined everything and repaired a bit of damage. It now works great.



I assume he didn't dissolve away the aluminium with sodium hydroxide. What did he do?

Michael Cienfuegos
6-Aug-2012, 13:58
I'm glad to hear that the problem has been solved. I was just wondering if you had ever managed to get the piece apart. :)