Todays update from Bodgers Lodge

[MuzzerParticipant @muzzer]

Rather you than me. It's 30-32C and sticky as hell in Guangdong right now. Just right for hanging around in hot factories!

Merry

[John Stevenson 1Participant @johnstevenson1]

Muzzer,

No decent factories in Guangdong, that's where all the sweat shops are.

Best factories are in the far north where it's cooler and less humidity.

[JESParticipant @jes]

Have a good trip to china. I for one will be looking forward to more postings from Bodgers Lodge.

JES

[Russell EberhardtParticipant @russelleberhardt48058]

Posted by John Stevenson on 05/06/2014 02:36:18:

Muzzer,

No decent factories in Guangdong, that's where all the sweat shops are.

Best factories are in the far north where it's cooler and less humidity.

I don't know about that. I've seen some pretty good factories in Shenzen including HP and an aerospace component factory with about 20 CNC machines working to micron tolerances in a clean room and that was about 15 years ago. Mind you I've seen some dreadful ones as well, including plastic moulding tools being made in a dusty open garage.

Have a good trip and enjoy the food.

Russell.

[John Stevenson 1Participant @johnstevenson1]

OK so been back a bit and back to the bodging – literally today.

First job was a slightly bent fan about 14" across.

Just needed a bit of a tweak and a swift smack with a hammer, bit of weld and add a bit more to balance it.

Then a quite nasty one.

Pump housing and the drive cage to go with it.

All the bolts had come loose at some point to the extent that one bolt was carrying all the weight and it snapped the whole of the mounting off on the cage and half the hole on the pump.

Cage was milled out to get square sides and edges and a piece of steel bar was welded and TiG brazed into position.

Then skimmed in the lathe to put the register back in.

Other side.

The housing was carefully built up 3 microns at a time with TiG Sifbronze weld, cleaned up with a dremel and then all the holes were helicoiled with 2D inserts.

Bit of a badgers arse day buy hey get to do some real precision jobs tomorrow when I cut all the gaskets out of 3 cornflakes boxes and a Rice Krispie box. Stay tuned.

[Les Jones 1Participant @lesjones1]

Hi John,
This is one thread I really enjoy reading. You always seem to come up with a very cost effective way of repairing things. Are the bottles in the background of the second picture from grateful customers or do you have some with your fish and chips when Ketan visits you ?

Les.

[John Stevenson 1Participant @johnstevenson1]

It's stage two of the central heating system Les and strategically placed there to piss the H&S Nazi's off.

[chris stephensParticipant @chrisstephens63393]

Hi Guys,

To paraphrase Nelson, "bodges, I see no bodges" , just quality get-customer-out-of-the sh*t repairs using years of hard won skills and intelligence, and without running to the, probably, non existent spares shop. Good on yer, John.

chriStephens

[John Stevenson 1Participant @johnstevenson1]

Greetings peeps.

Todays bodge is quite a common one.

Armature out of a fork truck motor, the one that drive the hydraulic pump for ancillaries. This one has suffered a pump seizure which in turn has twisted to Oldham drive dog off.

In the long distant past I have built these up with weld and machined them back but never felt happy about the strength of them even though I have never had one back. So now I choose to do them a different method that I feel is stronger.

First a very detailed CAD drawing of the armature is made.

Then the armature is run in a steady to get a dummy centre in the end to reduce the diameter down by a mill or so to get the weld transition below finished size.

Then transfer to the Blidgeport and mill a slot into the end, same width as the dog, 8mm in this case.

Next job is then to cut a piece of hardaswitchestitsium [tm] to act as a dog and fit it in the end.

Note the dog has purposely been cut narrower where it fits into the shaft to allow the weld to get hold.

Then it's all welded up.

Back in the lathe, on the steady which is still set up, face to length then small centre in the end, dispose of the steady and turn to the original diameter.

Jobs a good un and another £3 17s and 6d to add to the pension fund which at present rates should mature about 3 years after I am dead.

[jason udallParticipant @jasonudall57142]

John.
Do you ever feel your
” bodges” last better than the original build……
I would not be surprised.

[Gordon WParticipant @gordonw]

John, when you do these sort of jobs such as building up shafts by welding, do you have any problems with overheating the wires etc. ? No doubt you have some fancy welder, or do you use wet rags etc.?

[John Stevenson 1Participant @johnstevenson1]

Gordon,

No fancy welder at all, welder of choice is a BOC TransMig 285 amp max but never runs anywhere near this as it's only on 1mm wire but I can and do use any MiG welder that is available.

You can get these motors sticking hot, too hot to handle as they can run at about 120 degrees C in service at times.

Shellac baking or it's modern resin equivalent is done at 280 degrees C so heat is not the problem that many think it will be.

What is a problem on DC motors is the insulation sleeving between the shaft and some of the windings depending on design but these can accept heat, just not a lot of it at one time so you weld a bit, do something else, go back and do a bit more.

Rotors are never a problem as there are no windings or insulation, just an alloy core cast round the laminations and on these you can get them glowing red hot, it fact it pays to get them off the welding bench in this state as quick as possible, back into the lathe on a steady and then when the centre is applied and the job run it bends it back somewhere near straight as it cools in air.

[Gordon WParticipant @gordonw]

Thanks for that, the motor I'm looking at is a bit older and varnished windings. But will have a go at it on the basis of nothing to loose.

[StephenSParticipant @stephens]

John, I am nowhere near an expert on any of these things, but do have just one question about your repair that you may care to enlighten me about.

Looking at the original failure, I would regard the drive dog shearing off as a sort of "safety valve" maybe preventing the motor burning out after the pump seized.

With the repair being better than the original, where would you think something of that nature would now be, or what would give if the pump seized again? Or do you not think that is necessary?

Just seeking enlightenment and look forward to your reply. I do enjoy seeing your high-class "bodges".

[Les Jones 1Participant @lesjones1]

Hi StephenS,
If the designers wanted to design in overload device then it could be done better in the control electronics or by a shear pin in the drive to the pump. Also it would be easier to find a rewind company to rewind the motor than someone like JS that is capable of making such a repair.

Les.

Edited By Les Jones 1 on 25/07/2014 08:14:58

[John Stevenson 1Participant @johnstevenson1]

Stephen,

Les has answered for me but TBH that dog in this case is 18mm diameter by 8 mm wide and those DC motors are very powerful beasts probably best end of 5 HP so if the pump seized again it would still rip the dog off.

Most of these I have to do are not missing dogs but very badly worn as as they never reverse it's always the same pattern where opposite sides wear and you finish up with something like this, <>

[Gordon WParticipant @gordonw]

Shear pins are a great idea, until the operator decides they are breaking to often and upgrades to a HT bolt.

[Neil WyattModerator @neilwyatt]

A large part of my first job was winching rhododendron roots out of the ground. You'd slice a groove all round it, and winch a wire sling so it went underneath and cut the roots, guiding it with a spade. Some of these roots were big enough to park a car on.

The baccy tin full of Tirfor shear pins was essential equipment. You would not expect to regularly pop the pins on a 3-ton winch, but sometimes we did it more than once in a day. One day we had a JCB, a 3T and a 1.5T winch all together -pulling a tractor out of the bog. When we went home the day before you could still see most of the wheels, the next day only one front wheel and the can were visible. I was informed there was a JCB 'somewhere in that direction' that never got recovered, and I'm willing to believe that!

Much real bodging on that job, even removing a bent chainsaw clutch band (that kept tripping) just so we could finish a job.

Neil

[Gordon WParticipant @gordonw]

Neil- you weren't working near the Scottish borders by any chance ?

[John Stevenson 1Participant @johnstevenson1]

Probably HMP Sudbury ?

[Neil WyattModerator @neilwyatt]

I was a Community Programme Estate Worker at Ynys-Hir, so not far off John

I should add, the employer never knew about the chainsaw shenanigans!

Neil

[John Stevenson 1Participant @johnstevenson1]

Been busy but one broken shaft os much like any other broken shaft.

However got a nice one in today that interesting in that the methods can be used on many applications, it isn't all about full size engineering v model engineering.

Anyway got the big fan shaft in 90mm diameter and too long to fit in the lathe. It's a stainless shaft and the stainless Allen socket screw used to hold a very big fan on would not move and sheared the head off. Screw was 18mm diameter and being stainless and seized [ suspected it had galled in the shaft as stainless on stainless is prone to do ] drilling out with a hand drill would have been an exercise in futility.

So get it set up overhanging the bed of the mill.

As I say a bit of a brute, then using a 14mm carbide cutter belt a hole straight thru the screw, low speed, plenty of coolant and decent feed to stop it rubbing.

Then and this is the bit that's transposable to any ddicipline, the cutter was plunged back in moving the table in one direction until the threads were just visible and again in the opposite direction.

Result is you can then tap the screw out by making it fold up on itself and it also saves the thread in the hole.

Just a clean up with a tap and the jobs good to go.

As suspected it had galled in the hole and no amount of easy outs etc would have worked on this.

[rooferParticipant @roofer]

Fantastic thread…many thanks.

[chris stephensParticipant @chrisstephens63393]

Hi John,

So that's what easy outs are for, I thought they were hard inserts for plugging holes.

chriStephens

[Jack Foreman 1Participant @jackforeman1]

What an unexpectedly refreshing thread. Thank you John. You've made me chuckle. And at the same time, admire your innovation and skill.

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