# Resolver question



## nolabama (Oct 3, 2007)

Anyone have any suggestions as to how to press a gear on the end of the shAft without damaging them? 

Apparently beating the old gear on the new resolver with a ball peen hammer has less than desirable results. Not that I would ever consider such a caveman move like that. AMCI HT-20-16 nice short shaft that doesn't chuck up in a vice real well. 

Thanks in advance. No resolvers were damaged in the making if this post.


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## nolabama (Oct 3, 2007)

Auto correct changed shaft to shift 4 times. Duck that.


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## BT Electric (Feb 7, 2014)

If the end of the shaft is tapped you can use a bolt and a stack of washers to press the gear on the shaft. You will have to keep backing the bolt out and adding washers until the gear is fully pressed on.


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## nolabama (Oct 3, 2007)

Thanks. I hope it is then.


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## BT Electric (Feb 7, 2014)

If it isn't tapped, remove the rear cover to access the opposite end of the shaft, use a piece of round stock or similar roughly the same size as the shaft to support the shaft and place in an arbor press and press the gear on. If you have no arbor press a large c-clamp can be used if you are careful with the alignment when starting the gear on the shaft. Do not support the resolver by the housing in any way as the bearings are not designed for thrust loads and will be destroyed, same as using a hammer.


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## Big John (May 23, 2010)

I agree with the C-lamp method. I've also used a woodworking vise.


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## drsparky (Nov 13, 2008)

I thought I was well read in the electrical field but never heard of a resolver. New to me.:thumbsup:


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## 8V71 (Dec 23, 2011)

drsparky said:


> I thought I was well read in the electrical field but never heard of a resolver. New to me.:thumbsup:


Yeah, I haven't heard that term in a long time. They are really cool well made devices. Used to come across them in the old analog military stuff.


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## nolabama (Oct 3, 2007)

They are used in military targeting equipment from what I am told. I don't dislike them. We use it as a first choice position sensor for our bridges. Second choice is limits. Third is human. The human is the least reliable of the three.


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## nolabama (Oct 3, 2007)

Maybe I shouldn't say reliable but the human is the least sensitive. The damn thing has to be so far out of wack it's tearing things up for the human to notice.


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## 8V71 (Dec 23, 2011)

I was thinking that the RR must use them for the bridges given your work history. But RR bridges and precision resolvers just doesn't sound like they should go together. :laughing:


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## nolabama (Oct 3, 2007)

Precision is relative. We are allowed 3/16 of an inch by the federal Gubbament tolerances in lining the thing up.


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## JRaef (Mar 23, 2009)

It's not likely about the precision though. Resolvers, as opposed to encoders, are far far more rugged. Copper, iron, steel vs plastic, optical sensors and on board electronics. In a dirty nasty place like heavy machinery where mass and inertia of the speed/position sensor is irrelevant, I'd take a resolver any day. But I would not put a resolver on a high speed servo in a packaging machine running in a controlled environment. Too heavy, too expensive.

I've seen resolvers pressed onto large motor shafts when the motor is put on a slide adjusting base. They created a fixed block arrangement to hold the resolver in place, then used the motor slide base adjustment bolts to slowly press the motor into it. It's similar to the C clamp idea but for when the motor is too big to allow for that. It's hard to find a C clamp big enough to go around a 250HP motor and it can be a challenge to stand one on end in an arbor press...










I love the threaded shaft and washers idea. I've never seen it but for sure if it ever comes up again, I'm going to remember that. Thanks!


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## just the cowboy (Sep 4, 2013)

*heat*

Heat the gear or freeze the resolver. we just froze a shaft to get a gear on a small fragile motor


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## CyberKnight (Sep 3, 2013)

I usually put the shaft in a freezer for awhile to get it good and cold or pack in ice. then heat the gear and it will just drop on the shaft. Let it cool and your all set. Be sure the shaft and gear are clean while you are doing it. At times I have to tap it all together but not often.
This stunt works good for bearings also. I think its called a shrink fit. For heating a bearing I just use a good blow dryier to warm it up. Just hot enough that ya cannot touch it with your hand.


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## Jlarson (Jun 28, 2009)

nolabama said:


> Apparently beating the old gear on the new resolver with a ball peen hammer has less than desirable results.


:laughing:

Steal the mechanics bearing heater and dry ice maker.


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## micromind (Aug 11, 2007)

Depending on the conditions, liquid propane is a pretty effective coolant. It boils at around -40º, and will cool stuff real quick. 

But remember, it's more than a bit flammable........., plus it stinks something fierce!


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## BT Electric (Feb 7, 2014)

Loctite make a product called "Freeze Spray", it is used for helping to loosen stuck bolts but is also handy for shrinking a shaft slightly to help with installation. Much safer than propane


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