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New 2x72 motor problem


BKToad

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Brand is to remain nameless.  Unless I get more flak during the return process.  

Maybe you guys could tell me if I am off-base here.  Just came via fedex today.  Getting it setup, went to put the drive wheel on the motor shaft.  Will not budge.  Notice the key looks a little screwy.  Fiddle with the key a bit.  No help.  Remove the key and see this.  Am I crazy or is this not a completely ruined and unusable keyway?  Notice the bend/slant/crookedness near the end.

 

 

6CF5A562-390F-479C-B080-FA353410FA81.jpeg

59438450-4064-4011-8DB0-81512250056D.jpeg

E58D0A64-2E76-4BDB-9B98-5C42AB391CDE.jpeg

 

My point of contact, who I assume is the owner of the company, has agreed to have it shipped back and ship out a replacement.  Not really thrilled about waiting 2-3 more weeks to have an operational machine.  Is what it is.

 

what I don’t get is how this guy failed to see the severity of this flaw from these pictures.  I would think anyone who does anything with machines would take one look and see the problem.  

 

I even offered to have a local machine shop fix it and have him foot the bill.  Would have saved him a good bit on shipping costs.  His reply?  “I don’t want some local machinist to ruin or damage it.”  

How?  How could a machinist make it any worse?

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Good Morning,

Yes, it is askew. It means when they milled the slot, the shaft moved. Is it really a problem? Not necessarily, the shaft is true and the key stops the pulley from turning separately on the shaft. The key can be any length and the key just needs to be snug side to side, the pulley set screw pushes on the key. It won't/shouldn't cause a vibration.

On the other side of the coin, if you purchased new, you expect new! Rightly or wrongly someone made a boo-boo. I think that is called being a Human Being.

 

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Ayup, a crooked keyway alright. That might say bad things about quality control  or maybe just a bad day at inspection. I'd send it back even if I do know how to install the key and pully. Mistakes can happen to anybody. Does it run smoothly?

If you decide to use it give me a shout I'll tell you how to mount it.

Frosty The Lucky.

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12 minutes ago, swedefiddle said:

Good Morning,

Yes, it is askew. It means when they milled the slot, the shaft moved. Is it really a problem? Not necessarily, the shaft is true and the key stops the pulley from turning separately on the shaft. The key can be any length and the key just needs to be snug side to side, the pulley set screw pushes on the key. It won't/shouldn't cause a vibration.

On the other side of the coin, if you purchased new, you expect new! Rightly or wrongly someone made a boo-boo. I think that is called being a Human Being.

 

A little askew I can deal with.  I live my life a little askew.

 

Inserting the key in the keyway puts a slight kink in the key.  And the wheel will not go onto the shaft because of it.  

I thought about trying a shorter key that is the same length of the non-askew portion.  Didn’t know if that would potentially lead to other problems or premature wear.

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You don't have to slide the key down the keyway. Insert the key past the hinky bit and slide the wheel down the shaft, align it with the key and continue. :rolleyes:

If there isn't enough straight keyway to be functional then there's your answer.

Frosty The Lucky.

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9 minutes ago, Frosty said:

You don't have to slide the key down the keyway. Insert the key past the hinky bit and slide the wheel down the shaft, align it with the key and continue. :rolleyes:

If there isn't enough straight keyway to be functional then there's your answer.

Frosty The Lucky.

How much key is enough?  The last 1/3 of the keyway is the “hinky bit”.  The side farthest from the motor.  Do you think that if I shortened up the key to 2/3 length and put it on the non-hinky bit it would suffice?  Or should I just bide my time, send it back, twiddle my thumbs, and wait for a replacement? (That may or may not be as awesomely milled as this one)

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Oh wait, I remember now you're making a tire hammer and need the wheel out on the end of the shaft don't you? 

It probably isn't suitable as is, I'm thinking I'd send it back. If the replacement is as bad or worse would you want one of their products at all? That's money back time. It's when buying with a credit card pays, let THEM fight the seller.

Frosty The Lucky.

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As said above, you've got a responsive manufacturer offering to make it right, might as well take them up on it.

To answer your question about the key, there are a lot of different ways to make a key on a motor shaft.  A woodruff key for example is half round on it's long dimension and generally shorter than the length of the shaft.  Any "trapped" key design prevents the key from working it's way out the end of the shaft.

I've repaired a fair amount of motors that came in with the end of the key slot buggered up.  Some looked like they were hammered, others looked like they were dropped on the floor.  It's not a big deal to true them up.  If the key in the keyway fit was sloppy, we'd superglue shim stock to the sides of a key.  A few well placed divots from a center punch in the bottom of the keyway keeps the key from sliding back and forth in the slot.  

As you mentioned wear, it occurred to me to mention soft footing a motor.  That's when one or more of the motors mounting points aren't actually pulled tight to structural support.  A lot of motors have through holes in mounting "feet".  Just torquing everything down doesn't necessarily mean that the foot is hard against the structure.  Sometimes machines are crooked, sometimes motor housings aren't perfectly aligned.  If one or more feet will permit a feeler gauge to slide between the foot and the structure, the motor will be prone to vibration that prematurely wears out the bearings.  Clean, or shim as necessary to get full contact on all the feet.  I've encountered a few motor frames that would twist a foot up .010"  if the bolts weren't torqued in a certain order.  It's fairly common for soft-footed motors to come in with a wallowed out bearing race opposite the shaft end.  Cheaper motors tend to have end bells that don't have enough material in them to merit making sleeves to repair them.  

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