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Gallery, Projects and General => Gallery => Topic started by: John Stevenson on May 12, 2015, 03:30:56 PM

Title: Bodging - again
Post by: John Stevenson on May 12, 2015, 03:30:56 PM
Anyway got a right good job in this afternoon I can really get me teeth into or would have it if had any teeth left.

Two stage epicyclic gearbox that drives a turntable at the bottom of a special fork truck. The mast can rotate thru 180 degrees so it can pick off shelves whilst the truck is stationary. Real special, mast is 9 metres high in 5 stages and equipped with cameras etc.

(http://www.stevenson-engineers.co.uk/files/epycyclic1.jpg)

First stage on the plate is OK but on the output stage all the pinions are toast. Fortunately all the pinions are the same except the first stage has a smaller bore but possible to get decent measurements.

(http://www.stevenson-engineers.co.uk/files/epycyclic2.jpg)

And the measurements proved what I suspected when I saw these, that they are special, note the fat teeth. So that knocked nipping up to HPC gears and buying three off the shelf gears - damn.

20 teeth but cut on a 21 PCD, so turn a simple bar up to the OD and throw it on the 'gear hobber' which is thinly disguised as a Victoria U2 universal mill.

(http://www.stevenson-engineers.co.uk/files/epycyclic4.jpg)

And ten minutes later we get a stick of gears.

(http://www.stevenson-engineers.co.uk/files/epycyclic5.jpg)

Drilled, reamed, parted off and a tad of surface grinding we have three new gears.

(http://www.stevenson-engineers.co.uk/files/epycyclic6.jpg)

So just a tad less than an hour but in all fairness they now have to go over the road to the hardening shop which will have to be tomorrow now but they can't get a new turntable bearing until Thursday anyway.

A new gearbox from Mitsubishi is 2,200 and 3 week wait so should have some reasonably happy bunny's.
Title: Re: Bodging - again
Post by: dsquire on May 12, 2015, 03:48:20 PM
Hi John

Nice job you did there, you make it look so damnd easy.  :thumbup:

Cheers  :beer:

Don
Title: Re: Bodging - again
Post by: John Rudd on May 12, 2015, 04:41:48 PM
Hi John

Nice job you did there, you make it look so damnd easy.  :thumbup:

Cheers  :beer:

Don

John does make it look so easy doesn't he? Like a walk in the park...

Great job John...
Title: Re: Bodging - again
Post by: awemawson on May 12, 2015, 04:46:32 PM
That's 'cos he's so long in the tooth he's been doing it for centuries  :bow:

(btw there's an interesting pattern on the 'stick of gears', John, is that a trick of the camera ?)
Title: Re: Bodging - again
Post by: micktoon on May 12, 2015, 06:34:22 PM
Hi John , nice work as the lads say you have made it look easy  :thumbup:, I hope the customer does not read the post and expect to be charged an hours labour  lol.
  Will the hardening change any sizes , do you have to factor it in when making the gears ?
  Cheers Mick.
Title: Re: Bodging - again
Post by: John Stevenson on May 12, 2015, 07:20:34 PM
Andrew,
The marks are caused by the feed being constant but the hob has to do 20 turns for the blank to do one and invariably you have a high tooth on the hob. It is there but more visible than feelable.

If you play around with the hob to get the best position you still get the mark but it's then usually a longer curve. Ideally a hobbing machine should feed like a shaper, do one complete rev, then advance and not move until the next rev has been done but that makes it complicated and slow.

Mick,
Hardening usually shrinks everything, OD isn't critical in this case as it will be tenths but the bore could shrink. I reamed it with a 10.02 reamer because I had one and hoping it will still fit the 10.00 pins, if not a quick polish will suffice.
Title: Re: Bodging - again
Post by: steampunkpete on May 13, 2015, 02:24:56 AM
Quote
... a tad less than an hour ...

So quicker than going out to buy new gears and more fun.

Nicely done.
Title: Re: Bodging - again
Post by: mcostello on May 13, 2015, 09:59:55 AM
Keeps John in chips and pints and inspiration for the rest of Us.
Title: Re: Bodging - again
Post by: Joules on May 13, 2015, 10:25:50 AM
Very impressed John, it would take me at least 3 days on the shaper making them in Swiss Cheese steel.    :bow:
Title: Re: Bodging - again
Post by: Brass_Machine on May 21, 2015, 09:01:44 AM
And he calls it "bodging". Very impressive...
Title: Re: Bodging - again
Post by: Meldonmech on May 21, 2015, 10:12:19 AM
 
    Nice job John, envy the facilities you have in your workshop. Looks a very interesting.

                                                         Cheers David

                                   
Title: Re: Bodging - again
Post by: hanermo on September 16, 2015, 10:59:43 AM
Does the hob rotate the blank, or do you index it ?
Title: Re: Bodging - again
Post by: John Rudd on September 16, 2015, 11:34:51 AM
The hob rotates, cutting the tooth on centre, and part cutting the tooth above and below....as the blank is rotated...is my understanding...
Title: Re: Bodging - again
Post by: John Stevenson on September 23, 2015, 04:59:44 PM
This is more up Squire Mawsons street than mine, bit agricultural even for me.

Local scrapyard called round and dropped a hydraulic breaker off they have just bought [ cheap I hope ? ]

Had a bit of a hard life  and could I straighten the dipper mounting out and fit new bushes.

In a word NO. Trying to straighten this is on a hiding to nothing.

(http://www.stevenson-engineers.co.uk/files/Breaker1.jpg)

So chop the bent and damaged plates off, get a couple laser cut, thicker and with a bit more meat on and allow for heavier bushes.

Pic is part way thru the job, one plate ground off and new plate welded on. Close of play tonight and both plates are welded on and back on the breaker.
Tomorrows job is the 4 steel bushes to turn and weld in and then fit 4 new PU bushes to take 30mm pins instead of the original 1" to fit their machine.

Need to keep these people sweet and friendly scrap yards are hard to find nowadays.
Title: Re: Bodging - again
Post by: Bluechip on September 23, 2015, 05:13:37 PM
What's a 'PU' bush ? Polyurethane ? Surely not.

Dave
Title: Re: Bodging - again
Post by: John Stevenson on September 23, 2015, 05:20:46 PM
Sorry DU bushes.

(http://www.waikatobearings.co.nz/edit/image_cache/124365_p_480x480c0pcenter.jpg)

Got me P's and D's mixed up  :loco:

DU for bushes.

PU for gloves.
Title: Re: Bodging - again
Post by: awemawson on September 23, 2015, 06:21:51 PM
I was surprised to find that the dipper  bushes on my JCB 803 were nylon or some similar plastic - seem to hold up ok