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+--- Thread: A normal day at the office (/thread-1300.html)
RE: A normal day at the office - John S. - 04-09-2013
So tootling along all nice and steady today, made 4 stainless seal track sleeves, sleeved an electric motor housing and built up the end of a worn rotor where a gear fits.
Then it all kicks off.
Bane of my life these.
[attachment=4976]
Bridgeport varispeed motor rotor, they wear where the sheaves fit. I reckon I do about 15 / 16 a year and that's from just local repairers. So bung in the lathe and skim down undersize and build up with weld. You need to go under size because you want the weld transition point to be under the surface.
If you don't do this chances are you will get flaky patches on the joint line.
Straight off the welding bench, in fact it's still glowing a bit, don't worry about distortion, whatever you do it will distort so don't worry
just rectify it later.[attachment=4977]
Support on a steady, rough down to a couple of mm oversize then bung outside to cool naturally.
[attachment=4978]
Whilst the weld was drying this gig rotor arrived, simple job, spun the nose bearing and it's had to be cut off and damaged the shaft.
Easy these are, make a sleeve just a bit bigger than the bearing and big enough to go over the output diameter, turn undersize loctite and bang the sleeve on with a BFH then turn to size.
[attachment=4979]
This is where it went pear shaped, bunged the revolting centre in and the rotor is running off centre ??, so pick up with a big steady on the seal track which isn't damaged, rotor runs true but shaft is running out, seems something has bent this.
Ring company and tell them, they say do it and can we have it back for 10:00am tomorrow.
So skim under size all over as the lot needs doing.
[attachment=4980]
Drop onto purpose made barrow for carrying rotors, a sack truck is no good as with a long rotor you can't get thru doors and up gangways. This one was made from a propane bottle. the two brackets clip on the edges and have two bearings fitted, a very crude steady that lets the rotor rotate so you can weld round a journal.
Welding done, got to wait for this to dry.
[attachment=4981]
So get the bridgy rotor back and do the final diameters.
[attachment=4982]
So all finished except the keyway, circlip groove and the roll pin hole.
The big rotor will have to wait until tomorrow, off to the pub for a pie and a pint, bastard of a job but someone has to do it.
Problem tomorrow is can't use the centre in the end as it's bound to be out, no steadies I have for this lathe will run on the bit of shaft not welded and can't guarantee that it's true enough anyway.
Watch this space.
RE: A normal day at the office - doubleboost - 04-09-2013
Hi
John
Not bad for a first post
Is the "mig snott"you use just mild steel or something special
A mate of mine builds up loads of shafts he uses stainless most of the time
John
RE: A normal day at the office - John S. - 04-09-2013
(04-09-2013, 03:15 PM)doubleboost Wrote: Hi
John
Not bad for a first post
Is the "mig snott"you use just mild steel or something special
A mate of mine builds up loads of shafts he uses stainless most of the time
John
Can't remember the number of the wire but it's a semi high tensile wire.
I have three large MiG's 200A , 250A and 325A
The 200A is on normal steel wire, the 250A is on Stainless and Argon and the 325A is on High tensile.
This saves me having to mess with changing wires over, all the welders are also on a manifolds with separate valves so it's just a matter of switching the correct bottle on and the correct valve and start welding.
Also have a couple of TiG's on the same manifold system although one is a backup and is hardly ever used, the DC is playing up.
RE: A normal day at the office - Micktoon - 04-09-2013
Hi John , cheers for posting, it looks like you had plenty to do without having to take photos too so top marks.
Its always nice to see repair type jobs getting done and what works and ways around problems , I had been wondering about the mig wire but John beat me to it lol.
Keep up the good work and posting too
Hope you enjoyed your pie and pint
Cheers Mick
RE: A normal day at the office - John S. - 04-13-2013
OK good news and bad news. Found the camera so going to bore you with the end of this post.
We left the rotor with the whole end welded and the weld drying.
Now need to get a turned surface to get a steady on so the end can be single point bored to accept the revolting centre.
So this is an attachment i have found invaluable, a revolving 4 jaw chuck.
Just a standard chuck with a bearing mounted in the back of the chuck and another in the bossed backplate running on a morse arbor.
[attachment=5010]
Adjusted so the shaft runs true and then the original bearing surface is cleaned up but left oversize by about 1mm or 40 thou.
Now swap to a steady and rough the shaft diameter out.
[attachment=5011]
Because at this point I can't use the tail centre, I prefer to wait and see how the weld cleans up in case it needs a bit of filling in and if it's all one sided it can pull the shaft off.
because of this but to provide a bit of support and stiffening I had pushed an old ball race onto the shaft end using the revolving centre.
Once it's all cleaned up and roughed to with 1mm or 40 thou then the end can be single pointed.
[attachment=5012]
Once this is cleaned up everything should be running true to each other and the steady can be discarded with to be replaced by a revolving centre.
Unfortunately it was at this point I misplaced the camera [ I blame the aliens ] so the final turning to size and cutting anew keyway was missed.
RE: A normal day at the office - Highpower - 04-13-2013
RE: A normal day at the office - doubleboost - 04-13-2013
Nice repair John
The 4 jaw in the tail stock looks real handy
John
RE: A normal day at the office - the penguin - 04-13-2013
John,
things would be a lot easier, if you had a good Bridgeport.
RE: A normal day at the office - John S. - 04-13-2013
(04-13-2013, 11:18 AM)the penguin Wrote: John,
things would be a lot easier, if you had a good Bridgeport.
Do they make one ?
Got a Bligeport if that's any good ?
![[Image: Blidgeport.jpg]](http://www.stevenson-engineers.co.uk/files/Blidgeport.jpg)
RE: A normal day at the office - DaveH - 04-13-2013
Well that turned out nice
DaveH