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John Stevenson
01-21-2009, 05:05 PM
Well in a day anyway, work may not come into it.

So this morning bright and early [ well for me anyway ] I set out for work, the reverse of the 34 steps I had taken the night before when they dropped 25 motors on me for conversion to a smaller frame setup [ shorten shaft, weld keyway up, turn down from 19mm to 14mm and re-keyway, then slot the mounting holes in the end cover x 25 times - booooring

So 33 steps later and I fell over this pile of end covers, brake housings a rotor and a weird circular bit on the floor outside the door. Opens up and starts to get fire going, phone rings and this Herbert says did you find my parts ? Find them I bloody well fell all my length over them. I can see what's wrong with them except for the circular bit.

That's an impeller that goes on the long rotor.

Wot ?

Speaking slowly because it's early " Goes on the long rotor "

"Can't do the holes too big"

"It's worn"

Worn ??????????

http://www.stevenson-engineers.co.uk/files/wornimpellor1.jpg

That's about 38mm or 1 1/2"

http://www.stevenson-engineers.co.uk/files/wornimpellor2.jpg

The shaft is 24mm or a tad under 1"

Now I have seen worm things before but the shaft isn't that bad compared to the bore of the impeller, most of the original keyway is still there on the shaft but totally missing from the bore. Add to this two cracks into the bore from the webs and it's cast iron.

Phone goes again, any chance of it back for dinner ? Sure, but note I never said which dinner <g>

First off weld the cracks up then stiff in outside jaws on 3 jaw chuck and bore the hole out, it went out to 42mm before it cleaned up, that's about 1- 5/8".
Machined a slug up, pressed it in, loctited it and pinned it then bored it out to 24mm and stuck a 8mm keyway in.

http://www.stevenson-engineers.co.uk/files/wornimpellor4.jpg

Rotor was straight forward so won't go into that.

Leave all the rest they weren't important, then onto the motors.

http://www.stevenson-engineers.co.uk/files/rotors25.jpg

That's what 25 rotors look like ready to box up and go back first thing in the morning.

I HATE ELECTRIC MOTORS.....................................
.

SDL
01-21-2009, 06:17 PM
Are the bigger holes around the edge for balancing or some other function?

Does it need balancing? shouldn't think so from the size of the worm bore:D

Steve Larner

Bill in Ky
01-21-2009, 06:40 PM
Nice work sir!

ammcoman2
01-21-2009, 06:41 PM
I wager that if you botched a few you wouldn't get nearly as much business.

The fact is that you are just too darn good at your job. Or that nobody in the area is so thorough. If you want to slow down a bit you know what to do about pricing.

Keep up the good work - and the posts. I sure learn a lot from them, even though I have done a few DC motors and auto generators.

Geoff

ammcoman2
01-21-2009, 06:45 PM
Forgot to ask about the slug - did you use a roll pin or a solid one to pin it to the impeller?

Geoff

John Stevenson
01-21-2009, 07:14 PM
Yes spotted the balancing holes but no idea what this is off, never seen one like it before.

Anyway it's all stuffed up now I have splatted 4# of nickel weld all over it :D , the motor people have very good electronic balancing gear, I'll just mention it to them and then it's up to them.

The slug was drilled and tapped in three places to line up with the spokes and three 6mm allen grub screws fitted half in the bush, half in the impeller.

It's not so much being good as being quick. OK this one was a special but many jobs are borderline whether to repair or replace and if you are too dear you loose out.
What's better getting a regular small mouth full or a big bite and choke ?
Some of the jobs may sound cheap but even the small ones go for one hours minimum labour and if you can do a couple per hour it's not so bad.

That rotor in the picture I can easily do 3 or 4 in an hour because I'm geared up for it.
Quick change tool holders, 4 MiG's all with different wire and all manifolded to the same bottles, Plenty of different chucks and steadies, Keyway milling cutters set up in holders, DRO's on machines and many more time saving tools and fixtures.

motorworks
01-21-2009, 07:39 PM
"shorten shaft, weld keyway up, turn down from 19mm to 14mm and re-keyway, then slot the mounting holes in the end cover x 25 times"

John
Just wondering...
I do the same regularly, but I get "standard" motors and have to make them "metric"!

If you are shortening the shaft and turn from 19 to 14 why fill in the old key slot?
Won't the slot machine away.The key in 19-6 is 3.6 deep :)
or perhaps these are woodruff keys?

"What's better getting a regular small mouth full or a big bite and choke ?"

around here it's:
Shear for a life-time, butcher once!

John Stevenson
01-21-2009, 07:56 PM
If you are shortening the shaft and turn from 19 to 14 why fill in the old key slot?
Won't the slot machine away.The key in 19-6 is 3.6 deep :)
or perhaps these are woodruff keys?



All my tables give 6mm key as 3.5 deep not 3.6.
So 3.5mm deep on a radius of 9.5 so that leaves 6.0

6.0 x 2 is 12.0 that's under 14 and leave a witness mark in the shaft.
can't pick it up and use that because 14mm is on 5mm key.

motorworks
01-21-2009, 08:07 PM
Yes
You are Right John
It will leave a mark!

Engineers Black Book says 3.6 max....
I will be looking for a refund in the AM ;)

Frank Ford
01-21-2009, 08:17 PM
John -

I always enjoy seeing your repair projects - there's so much to learn.

Having spent better than four decades doing repairs for a living, I sure have those I get to do more often than I'd like, too, but they pay the bills:

http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59D28PegheadViews/59d28phead08.jpg

madman
01-21-2009, 08:26 PM
John i havent worked on any Electric Motors BUT im beginning to Hate them also,. Yech Got to be a boring Repair time after time. I get weird Jobs and am SO HAPPY when theyre done and gone but they do tax my feeble mind to the bursting point time after time But I LOVE IT LOL Madman

John Stevenson
01-22-2009, 04:24 AM
Frank,
I would have no idea how to go about that.
Probably the best I could come up with would be a big G clamp and a tube of no nails and I'm not joking.

davidh
01-22-2009, 05:30 AM
John -

I always enjoy seeing your repair projects - there's so much to learn.

Having spent better than four decades doing repairs for a living, I sure have those I get to do more often than I'd like, too, but they pay the bills:

http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59D28PegheadViews/59d28phead08.jpg

im going out on a limb here, a few steel rods, buried from the back with accenting wood plugs covering them ? beautifully sanded and re-stained and with new decals from Martin ?

my son tipped over his new les paul and cracked the neck. he wouldnt let me touch it but found someone that did and you;d play hell trying to find the repair. much like you, the guy was a "wood wizzard" .

so how do YOU fix something like that.

(john, i also steal threads):D

Circlip
01-22-2009, 07:07 AM
"It' Worn"

Yes John, I can just imagine the conversation, Cleese and the dead parrot?

I used to have to stay behind at times to make sure the Muppets didn't harm themselves in the overtime, and kept simple multiple component jobs on one side that I could do in the office without creating a mess. These became know as "Ian's mindless tasks" cos once you got into the swing, it allowed youto battle on and drift, thinking of new ways to wind the natives up. :D

Regards Ian.

Did you say the impellor was made out of IRON???

I see.

Rustybolt
01-22-2009, 07:34 AM
John -

I always enjoy seeing your repair projects - there's so much to learn.

Having spent better than four decades doing repairs for a living, I sure have those I get to do more often than I'd like, too, but they pay the bills:

http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59D28PegheadViews/59d28phead08.jpg
That looks like a very expensive guitar.

Frank Ford
01-22-2009, 08:05 PM
It's a 1957 D-28, and worth a fair bit of dough. The owner had it out on a stand and his three-year-old ran by and clipped it, sending it halfway across the room. He followed the description of the accident with, "I'm thankful that my son wasn't hurt." Good man.

The result was quite nice, but it was a complex job:

http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59D28PegheadViews/59d28phead36.jpg

I did the job in 2002, before I had a full size mill which would have helped a bit.

Here's the whole process:

http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59D28PegheadViews/59d28phead36.jpg

tony ennis
01-22-2009, 08:13 PM
I'd take an old Martin to a luthier. And yes it would be an expensive fix.

Les Pauls and other Gibsons are notorious for breaking their headstocks in that way. Fall off the stand... snap. The reason is that the headstock is a scarfed joint, not bent, laminated, or otherwise shaped wood. It's a weak joint.

Looks like Martin headstocks are also scarfed.

You won't see a Stratocaster or Telecaster with that injury.

plastikosmd
01-22-2009, 08:44 PM
frank, was the link suppose to be to the process in which you used to fix it? It is just a link of the same pic. I was lookin for some good reading/cool fix

thanks

websterz
01-22-2009, 09:03 PM
I'd take an old Martin to a luthier. And yes it would be an expensive fix.

Les Pauls and other Gibsons are notorious for breaking their headstocks in that way. Fall off the stand... snap. The reason is that the headstock is a scarfed joint, not bent, laminated, or otherwise shaped wood. It's a weak joint.

Looks like Martin headstocks are also scarfed.

You won't see a Stratocaster or Telecaster with that injury.

If he was the best luthier you could find would he be the...

...get ready for it...
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...here it comes...
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Martin Luthier King?:D

dp
01-22-2009, 09:44 PM
frank, was the link suppose to be to the process in which you used to fix it? It is just a link of the same pic. I was lookin for some good reading/cool fix

thanks

Find it here: http://www.frets.com/FRETSPages/Luthier/Technique/Structural/BrokenHeadstocks/HybridRepair/59d28peghead.html

davidh
01-22-2009, 10:26 PM
excellent repair. hide glue, aye ? hummm ! i/ll be in touch. . . .
im impressed.

you do excellent work sir.