Member postings for John Stevenson

Just let me check my 0 - 1 Ell micrometer................................................

Must be some short memories if it takes 5 years to answer a post

Is it cold outside today ??

If the bore and the OD are machined at the same setting why would it not run true ?

We have many on here who post they can turn over 20" to a taper of less than 0.01mm and now we have other querying what should be a very simple operation.

Come on lads you can't have it both ways.

Micheal you have lost me on this one ??

As I have been doing PRACTICAL engineering , man and boy for 167 years [ or so it feels like on some days ] and have all sort of gear from knotted string to DRO's via digital calipers WHY would I need to know 1 1/4" equalled 31.75mm ?

Perhaps I don't study useless theory enough or the padding in my armchair is too lumpy ?

I feel this thread has run it's time out.

Move on lads, nothing to see.

No MiG Mark.

It's just an AC/DC welder with stick [ MMA ] thrown in.

I rely on two large industrial 3 phase MiG welders. A BOC TransMiG rated at 325 amps running steel and an ESAB 250 amp machine running stainless, both on 1.2mm wire.

I still have a single phase Camarc 200 A on 1.0mm wire but have given this to my grandson as it can run 0.8 wire as he's restoring an old American Ford F250

Colin,

Had it about 5 years now so the exact model I have probably isn't made any more but this is the closest I can find.

**LINK**

As regards looks and features. The current model is different in that it's all in a sloping case. I paid about £420 direct from China when I was over there, they should have cost about £600 at the time but the newer design is around £750 now.

The 200 amp AC/DC from someone like R-Tech is just over a grand but you are paying for UK support.

Fuse in a holder either on the rear of the machine or front panel, one of the unscrew with a thumb nail type.

Does it have a separate E-Stop switch or rely on the No-volt switch ? If it has an E-stop check it hasn't been pressed by accident. [ Don't ask ]

10A if I remember right.

Again as John R has said, chuck guard? guard covering the change gears on the end ?

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Negative thoughts Moriarty.

Have a little faith Baby

This is the 40mm boss welded into the 8mm stainless plate with the cheap Chinese TiG.

Could be better at the bottom as regards presentation but not that worried as it needs facing off.

I have recently had two new lenses fitted to my eyes and not settled down enough to get my new glasses so I do have a problem at time focusing up close but once I get the new glasses this should cure things.

Outer vane TiG welded. DC @ 110 amps 3.2mm tungsten.

That was enough to pump enough heat into it to get the whole vane glowing dull red.

People take the pi$$ out of these Chinese welders but if you buy a decent one and not a budget one they are awesome compared to what we had to weld with 10 years ago.

I have now sold my BOC TradesTiG as compare to this it was a dinosaur.

Never touched this at all, just works out the box [ including all the gas fittings ]

Longest weld I have done with this was in 5mm thick alloy on a pickup tailgate where a digger bucket had swiped it. 40 minutes continual welding, No idea what the duty cycle is on this machine.

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Hang about Ian, I was coming to you.

In this instance, then no, as two pumps are needed and have been sourced but with cast impellers. The bits needed have already been sourced and cut. So these two are a done deal.

Can I use the idea in the future? Possibly but as my laser cutters are limited to 20mm and I have no water jet cutters who I deal with then I'll be the new boy on the block, wanted a very small order so I'll be back of the queue and probably get ripped off to boot.

That's usually how it works.

I'm not convinced that the hydrodynamic shape is needed for this application, which it turns out is to drain a waste chemical into disposal vats.

i have seen these types of pumps with straight vanes and parallel vanes. You only have to look inside a subs pump on a lathe to see how crude they are.

I could have milled it from the solid but this job like most repair jobs is only worth a certain price, go over this and you get no more jobs of that type. Keep withing what they deem acceptable and they keep coming back.

Anyway job is now nearly done. Impellers are finished but they messed the order up and only cut one wear plate, so I'm collecting the second plate together with 50 stepper motor brackets tomorrow afternoon on the way up for my weekend cuddle with the Delectable Debs.

For the person who asked there isn't a step in the thick wear plate but as it's 16mm thick they set the focus at mid point so the cut is made up of two diverging angles, albeit very slight but it gives the step impression.

Doesn't matter in this case as they have been cut a couple of mm oversize to skim up in the lathe.

Now why didn't I think of that at the time ???

One hole is right on the edge but it could have been moved in. Note to self to alter the DXF before it goes to the laser cutters for the next batch.

Steve,

I have taken on board that the vanes in the original are shaped which is not a lot a can do about without spending a lot more money.

But by the same ruling the vast majority of impellers i see on pumps have parallel vanes, some are even built up this way as separate items and welded or riveted.

The ends will be radiused before welding to break any sharp edges. Two pumps are being modified and then go into service and these will be monitored. At present the life of a pump is 10 months to a year before erosion wears the impeller out. If these can extend the life then there are more to do.

I think I could be something a lot better with £200.

I have one on my TOS lathe and never use it. By the time you have swapped the right gear to match the thread [ 3 gears on mine ] and messed about plus you have the change of stuffing up at every engagement I find it's far quicker to power back with the half nuts still engaged and this is doing metric threads on a metric lathe.

OK been a long while since I resurrected this thread but doing an 'interesting' job at the moment.

One picture of a before and part way thru shot.

Top right is a cast iron impeller out of a pump that pumps ? something ?

But whatever it is doesn't need to be in contact with ferrous materials and a stainless impeller or pump isn't available in this size at an affordable price, plus a few are needed.

So initially drew it up and was going to machine it out of a solid lump of 5" diameter 316 stainless but with the material costs and machining time on the CNC it was a non starter.

So Plan B.

Get the laser cutters to cut a back plate and three vanes per pump. At the moment only two sets have been cut until they have been tested out.

The vanes are in 8mm 316 stainless and have pegs on the ends at 8mm square which are turned into round pegs to fit the back plate. The vanes are then bent on the hydraulic press so the pins fit the holes and this 'should' give the correct radius for the vanes. A stainless boss will also be welded in to fit the motors.

So end of play today, everything is ready for welding tomorrow.

The other plate, top left is the wear plate that fits over the impeller, included it in the shot just as an example of what the latest series of fiber lasers can do. This is 16mm thick but they can go up to 20mm. Quality is quite good but the ID and OD need cleaning up by about 2mm

Correct.

It would help if you moved to a lift up screw cutting tool as mentioned in this thread.

**LINK**

That way it saves having to wind out, you just reverse and put the new feed on as the tool is returning.

There is a video of it here.

**LINK**

A bit like Clarkson who did publish instructions on how to tighten an autolock chuck up in that you don't leave a gap but let the cutter do the tightening ??

But every tool maker I know leaves a gap or the tool offsets go to hell in a hand basket when it self tightens ??

Must be right as Clarkson says it is but rather a moot point as industry has moved on to ER's

Personally I think Jacobs should have stuck to making cream crackers, all mine were sold on or scrapped years ago and have been on keyless for ages, usually good imports.

That is actually the spindle chuck that doesn't have a chuck key. The paragraph in question refers to the Camlock fitting.

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In 1946 UNF would not have been popular, especially with a firm entrenched in the 1930's

Edited By John Stevenson on 24/01/2017 21:54:40

Howard,

As far as I know it is still on but it really depends on Lou and John Rex and family who so kindly donate the space free of charge.

I am still prepared and look forward to doing it.

As a side note I PM'd Michael W over his original query and offered to do a few for him if he could fit into my time scale.

So as not to make this into a commercial post if anyone else is interested then please drop me a message.

Over a course of two weeks I have to setup to do a bunch of cutters from three local firms so slipping a few more into the mix doesn't hurt but it has to fit this time scale.

Once I receive Michael's cutters and have ground them and sent them back, perhaps he'll post on his experiances and the finished job.