Author Topic: Retlas "Manchester" Dynamo  (Read 15696 times)

Offline samc88

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Re: Retlas "Manchester" Dynamo
« Reply #30 on: November 08, 2020, 09:41:46 PM »
Nice work, I didn't realise how big this was until I saw the body mounted on your lathe

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #31 on: November 09, 2020, 08:30:08 AM »
Yes Sam it’s quite heavy, I hope my Retlas engine will be capable of driving it.

Andy

Online Roger B

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Re: Retlas "Manchester" Dynamo
« Reply #32 on: November 09, 2020, 11:08:11 AM »
That's looking good :praise2: As Sam says it's quite a beast  ::)
Best regards

Roger

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #33 on: November 09, 2020, 06:42:59 PM »
Thanks for the compliment Roger, fortunately for me the dynamo is pretty straightforward compared with the exacting standards with your injectors and carburettors which I follow.
Andy

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #34 on: November 09, 2020, 09:56:13 PM »
Almost finished milling the oil chamber in one of the pedestals this afternoon. I used a 1/2" slot drill taking 0.015" to 0.020" deep cuts forming the slot which is 1.375" wide reaching a depth of 1.75" after about two hours, a slow process but I prefer to take it easy.
I will have to settle for a chamber slightly smaller than the drawing, there isn't enough pedestal casting for the chamber to have a length of 1.5". Tomorrow I'll deepen the chamber to 2" which is as deep as my slot drill can reach.

IMG_2292 (2) by Andy, on Flickr

IMG_2293 (2) by Andy, on Flickr

IMG_2302 by Andy, on Flickr

Andy
« Last Edit: November 11, 2020, 11:25:17 AM by Chipmaster »

Online Roger B

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Re: Retlas "Manchester" Dynamo
« Reply #35 on: November 10, 2020, 07:41:12 PM »
Thank you Andy  :) Although I know there are people following along with these things I am doing I sometimes feel like the strange kid playing on his own in the corner (mind you that sums up my school life  ::) )
Best regards

Roger

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #36 on: November 11, 2020, 09:34:42 PM »
Having finished the long job of milling the oil chambers in each of the two pedestals I decided to use ring oilers as shown in the drawings. Originally I was going to use the 2.5" long plain bronze bearings with an oil hole in the centre for lubrication.

Here's a view down into the oil chamber,

IMG_2315 (2) by Andy, on Flickr

The drawing,
Bearing and oiler by Andy, on Flickr

I'll need to machine a small internal groove in each of the four ends of the pedestals and drill small holes for escaping oil to flow back into the chamber. The length of my bronze bearings will have to be reduced and a suitable slot milled across the centre for the oil rings.

IMG_2328 (2) by Andy, on Flickr

I wanted to make sure  that the oil chambers were large enough. Looks promising, I intend to run the 3/16" wide rings in a 5/16 or 3/8" slot.

 IMG_2326 (2) by Andy, on Flickr

Andy

Offline Jasonb

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Re: Retlas "Manchester" Dynamo
« Reply #37 on: November 12, 2020, 07:10:55 AM »
Is the idea that the shaft will cause the ring to slowly rotate thus bringing up a fresh supply of oil from the bottom of the pocket?

Unlikely to be a factor on a model but on something that may have run for many hours was there a risk of wearing a groove into the shaft?

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #38 on: November 12, 2020, 08:20:51 AM »
Hi Jason, yes the ring’s lower end dips in oil, as it rotates the oil is carried and deposited on the top of the shaft then travels out into the bearing. The rings are light so I agree, they’re unlikely to wear a groove into the shaft. Ring oilers are said to be common in slower stationary engines. I used to own a Lister A type stationary engine that used ring oilers on the main bearings.

Andy

Offline Alyn Foundry

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Re: Retlas "Manchester" Dynamo
« Reply #39 on: November 12, 2020, 11:39:25 AM »
Wonderful !

I think this might be a " first " Andy.

In my youth I came across many machines lubricated in this manner. The Water company had many pumps still running from the early part of the 20th century. Some had ornate Glass and Brass covers so you could see them working.

I'm beginning to wonder if I haven't given enough " meat " on the casting to provide room for the oil return passage? The answer will soon be apparent, methinks....

Cheers Graham.

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #40 on: November 12, 2020, 12:50:01 PM »
Hi Graham. if drilling the oil return hole looks as though it would break out of the casting an alternative could be to form a small channel - like a gutter, in the bore of the iron casting directly beneath the bronze bearing. That should return oil to the chamber assuming the dynamo is level. I would use a tiny grinding point in a Dremel to do it, what do you think.

There might be other possibilities perhaps involving external pipe work but that may be difficult to seal.

A web in the casting below the bearings would make drilling the oil return hole safer.

Andy
« Last Edit: November 15, 2020, 10:29:13 AM by Chipmaster »

Offline Alyn Foundry

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Re: Retlas "Manchester" Dynamo
« Reply #41 on: November 12, 2020, 02:14:08 PM »
Hi Andy.

Agreed, you could also mill a corresponding channel on the underside of each Bronze tube too.

The " flow " will be viscosity related, if too small a hole is provided then the oil will capillary rather than run.

Thirty four years on and we're still in the development stage lol.... :)

Cheers Graham.

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #42 on: November 12, 2020, 08:47:10 PM »
This afternoon I machined the grooves to catch surplus oil and drain it back via 1/16" holes into the oil chambers inside the pedestal castings. It is almost two weeks since the pedestals were bored out to 1". I left the angle plate undisturbed on the faceplate in case I decided to attempt the ring oilers in the drawings.

It didn't take long to machine the four grooves, I decided to make them 0.080" square.

 IMG_2330 (2) by Andy, on Flickr

IMG_2331 by Andy, on Flickr

It was necessary to form a notch using a Dremel with a grinding point so that I could get the best angle for the 1/16" drill. The angle was by judgement depending on how thick the casting appeared to be, I think I was lucky, the set up was extremely dodgy! Reckon the 1/16" holes are very close to the surface of the castings so no fettling in this area, will probably add a layer of Milliput or JB Weld to achieve a smooth surface.

 IMG_2335 by Andy, on Flickr

Green wire to show where the oil drainage holes emerge in the oil chamber.

IMG_2332 by Andy, on Flickr

Andy

Offline Chipmaster

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Re: Retlas "Manchester" Dynamo
« Reply #43 on: November 13, 2020, 09:25:29 PM »
This afternoon I completed the bearings. The bronze bearings were reduced from 2.1/2" to 1.1/2" - the distance between the oil collecting grooves in the pedestals. 5/16" Slots were then milled across the centre of the bearings down to about half their diameter. This gave ample  contact to have the oil rings rotate with the shaft.

 IMG_2349 by Andy, on Flickr

In this picture looking through the bearing the oil ring is resting in the slot
IMG_2356 by Andy, on Flickr

IMG_2363 by Andy, on Flickr

The bronze bearings can be pushed into the pedestal casting by firm finger pressure, 4BA grub screws keep them in place at the moment but I may use a low strength grade of Loctite for the final assembly.

IMG_2366 by Andy, on Flickr

Andy 
 

Offline Johnmcc69

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Re: Retlas "Manchester" Dynamo
« Reply #44 on: November 13, 2020, 10:11:42 PM »
 :ThumbsUp:
 Looking good Andy! Lot's to be learned here!
  :popcorn:
 John

 

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