Todays update from Bodgers Lodge

[MWParticipant @mw27036]

I could only dream of owning one of those moon sharp'ners. At £700 a pop i'd need 7 times what my bank balance will allow for. Would make life alot easier though, end mills are dreadful for going dull. I'll probably need to actually learn stuff and own a thin wheel to sharpen each edge. One of the cheap jigs will probably allow for it. If you need to remove alot of material with small sizes, don't bother with an end mill, side cutters and slitting saws are made for that. 

Michael W

Edited By Michael Walters on 10/08/2016 16:33:45

[Raymond AndersonParticipant @raymondanderson34407]

Hi Jason, thanks for the info, no, I've not seen the test that you did in MEW . I never actually thought about cutting off the worn flutes Good idea. I will have to do more research on the EMG as it could be very useful if as you say I cut off the worn flutes. I get me cutters sharpened for free, but sometimes I have a few days to wait so the EMG would solve that

cheers.

[John Stevenson 1Participant @johnstevenson1]

OK had a bit of time tonight but fast forward a bit as I was driving home afterwards I realised why this is a helical gear. The drive is take from the feed rod by a sliding worm that can select either sliding or surfacing feeds, so the helical is the angle of the worm, Duh !

 

First start pic, nothing different from the other day other than I have found a bronze ring that will fit.

One thing I have done is tapped a hole in the gear so I can fix it to a mandrel, the screw can be discarded afterwards.

 

Gear turned down and ring pressed and loctited on and a couple of tapped drive screws fitted for added safety.

 

 

Blank mounted on the hobber, head set over to 2 degrees and bed set over to the lead angle of the hob. Just touching on the blank at this point so I can zero the knee and apply 0.135" depth of tooth cut.

 

 

Better shot of the hob in relation to the blank, just needs the feed adding and we are ready to go.

 

 

Gear cut, as it was bronze it cut really easy and it was possible to do the gear in one pass, eight minutes start to stop.

 

 

Gear all cleaned up and finished, need to drop it back Friday as he's not there tomorrow and go skip diving

Edited By John Stevenson on 10/08/2016 21:25:30

[Nicholas FarrParticipant @nicholasfarr14254]

Hi John, a very neat job and a neat way of doing it. I have a gear that I may well try it out on, maybe, one day.

Many industrial worm drive reducers were made this way in years gone by. I used to overhaul a lot of David Brown boxes of various sizes years ago.

Regards Nick.

Edited By Nicholas Farr on 10/08/2016 23:22:12

[John Stevenson 1Participant @johnstevenson1]

Simple little job today, job not really of interest as chances are no one will ever be asked to replicate this but posting it for the method and using new toys.

 

*Warning* could be a blatant plug or two .

 

Job in question.

 

It's a fan motor that needs replacing with an off the shelf new unit. Now at one time this type of frame was an option.

They have tapped holes at 4 place on the outside so long studs can hold it central inside a ducting system. However they have long since disappeared off any manufacturers list.

What they did offer instead were angled feet to basically do the same thing but these have also disappeared.

So occasionally I have to make angled feet, next picture.

 

 

Now this is the interesting bit. Couple of angled feet milled out sat on the motor at the top and I now need to pick the hole centres up from the new motor.

 

*Blatant plug *

Whilst we were in China last I saw these threaded transfer punches and got Ketan at ARC to add them to his list and I thought people would be interested in them, also because I wanted a set as well.

Up to now I have been screwing an allen grub screw in, wrong way round , putting the bit on and whacking it then centre punching in the centre of the ring it left. Occasionally I get the damn screw stuck though and no way to get it out.

 

These threaded transfer punches have a small hexagon on the top and the set comes with a tubular spanner to fit them and remove them so no getting things stuck any more.

Two M6 punches fitted in the holes and one of the M8's laid on top so you can see what they are.

So got a couple of sets to do the whole range and fitted them into a nice spare wooden box I had and marked it up. Nice things laser engravers

 

 

They don't come in an engraved box, just the plastic trays you see here. i have done the engraving.

 

Anyway holes marked, drilled, counterbored and tapped and finished the job.

 

 

Edited By John Stevenson on 19/08/2016 20:21:45

[PeroParticipant @pero]

Well plugged Sir!

I have been faced with the same problem on a number of occasions (household repairs rather than model engineering) and have never found a really successful solution.

I will be adding a set to my next order from Ketan.

Pero

[Thor 🇳🇴Participant @thor]

Nice job as always John. I made a couple of sizes of my own threaded transfer punches. There is a point in the centre and a couple of thin sawcuts at the edge so I can get them out afterwards, using a small screwdriver. Well, I guess I don't have to make more of them anymore.

Thor

[frank brownParticipant @frankbrown22225]

I have made one also. To simplify things, my saw cut (to unscrew the beast) is purposely off centre, so as to leave the central "pip" to centre punch for the hole. The slot is only to unscrew the screw, so does not have to meet the latest NASA spec.

Frank

[JasonBModerator @jasonb]

Can also be made by grinding a point on an old allen key, cutting of a suitable length and loctiting into a grub screw. Thats blown my xmas present from Ketan

Edited By JasonB on 20/08/2016 10:20:40

[mark costello 1Participant @markcostello1]

They have been available "across the pond" for ages. A word to the skint from a skint, they can be used with homemade threaded studs saving not having to buy every size and flavor of thread in the universe.

[VicParticipant @vic]

Nice job on the gear John.

[John Stevenson 1Participant @johnstevenson1]

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

[SteveMParticipant @stevem36008]

Interesting job indeed John. I've no doubt that your welded solution will have the strength to last the course, but I wonder if the shape of the vanes may cause a problem. It's looks from your picture as if the original impeller has hydrodynamically shaped vanes with rounded ends which will shift the fluid efficiently. Having said that it also looks as if the surfaces have been left rough from the casting.
The regular shape and square ends of the new vanes may cause turbulence and/or cavitation which would reduce performance, but the surface finish looks much smoother.
It'll be very interesting to see how it works out.

[John Stevenson 1Participant @johnstevenson1]

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.

[Ian PParticipant @ianp]

Couple of points, What is it that the Fibre laser has done to the 20mm wear plate? (It looks like the edge has a step or rebate)

The vanes look to be about 25mm? high, if this is a thickness your laser cutter company can cut in SS then you would have control over the profile solving any possible hydrodynamic problems. The vanes could also be created by stacking 2 or 3 thinner cut parts and be aligned with dowels for welding.

Ian P

[JasonBModerator @jasonb]

Ian, read again vanes are 8mm material then bent. There is one laying on teh unassembled plate.

JohnS, be interesting to see how your 3in1 welder copes with this job

[Brian WoodParticipant @brianwood45127]

Hello John,

​I follow these varied exploits of yours with interest and this job is no different.

​With your eye for efficiency and elimination of unnecessary work, I am though curious as to why the vanes were made with square pegs which you later turned round to locate into the back plate, rather than simply fitting round pegs to them in the first place.

Regards
​Brian

[John HaineParticipant @johnhaine32865]

Posted by Brian Wood on 26/01/2017 08:49:25:

…. I am though curious as to why the vanes were made with square pegs which you later turned round to locate into the back plate, rather than simply fitting round pegs to them in the first place…

'Cos they are laser cut at the same time as the rest of the plate?

[Neil WyattModerator @neilwyatt]

Because you can't fit a square peg in a round hole?

[Chris GunnParticipant @chrisgunn36534]

Neil, it depends how big your hammer is!!

[JasonBModerator @jasonb]

But if the holes were made to suit the across corners size of the square you would be able to fit the square peg in the round hole

[Ian PParticipant @ianp]

Jason

It was the height (axial length) of the vanes that I was referring to. Nowadays Laser (or water) jet cutting of steel and other materials up to several inches thick is not uncommon so I was speculating that John could have cut the vane profile direct and eliminated the bending stage.

I frequently use the SPiRH technique with laser cut parts, I also use a line of small holes where bends are going to be as I dont have bending equipment (other than a vice). This is only useful if the holes do not matter on the finished product.

Ian P

[richardandtracyParticipant @richardandtracy]

Does anyone remember the Lindsay Publications series 'Echoes from the Oil Country'? General workshop magic from a machine shop foreman by the name of Bill Osbourne. Always read those books with a sense of awe at the general all round competence & ability. Same feeling as I get when reading this thread.

As an aside, I had a look on Google Earth for the towns Osbourne mentioned. Pit Hole, where he worked, is now 5 buildings & a preserved railway halt. Oil City, once with real estate values double that of central New York, doesn't exist any more. The last buildings were demolished in the 1960's, though the street layout is marked on the road overlay. Sad really, and astonishing, how ephemeral towns seem to be in the US.

Regards,

Richard

[John Stevenson 1Participant @johnstevenson1]

Posted by JasonB on 26/01/2017 10:12:00:

But if the holes were made to suit the across corners size of the square you would be able to fit the square peg in the round hole

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.

[Ian PParticipant @ianp]

Was my idea of creating the hydrodynamic profile by cutting the vane out of thicker material not a go'er?

Ian P

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