Postman Cometh Part 2

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Onto the crankshaft.

This is the supplied casting.

However.! I propose to alter the design slightly as I hope for this engine to actually do some work.

1) Beef the diameter up slightly.

2) Add additional extra outboard bearing making 3 in total on a pedistal (similar in style to the James Coombes and Victoria but slightly bigger) as I feel this will reduce 'whip' on the shaft and provide extra lateral support upon it at the point of the pulley.

3) Increase the length of the shaft to facilitate the extra bearing.

4) Make the webb of the crankshaft so that it has counterweights for hopefully smoother running. (and look 'prettier' . )

Avante' :-

Nick

Edited By Nick_G on 08/11/2015 12:38:09

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Next onto the parts that will make the crank web.

I turned some bar down to 2 1/4" and faced it off. I would really have liked to have used the flange jaws in the chuck. But I would not have been able to then get the parting tool in.

Formed a recess and drilled and reamed the center out.

Parted off a bit on the fat size to allow me to reverse in the chuck and make an accurate width.

Obviously 2 need to be made.

I can now split the size by 1/2 ( plus a smidgin ) to give me the final width for each side of the web.

I now need a hole for the big end and to carve out chunks from each side to form the counterweight. The look of each I am yet to decide upon. Think it may be best to temp bond the 2 together when making the holes for the big end.??

Also undecided if to bond and pin the sections with 638 or to silver solder. ??

Nick

Edited By Nick_G on 15/11/2015 21:51:05

Hi Nick nice work, your builds are very interesting to follow thanks

Mal.

Ideally the hole could have been done while you had one lump of metal, If your DRO is now working and you can accurately locate centre then no real reason to do them as one, if you are not sure of being able to set them up for equal offset then stick together. Solder construction for me.

Looking good, smashing, super work, etc now you should not be feeling depressed.

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lol . So when do you want Belmarsh 'Belinda' to call.

Nick

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Work on the webs continues.

Deciding which back rake angle to go for. - On the advice of Jason I went for 30 degrees.

Getting there now.

Then a blip of heat to break the loctite bond.

So it will soon be time for me to have a go at silver soldering for the first time. If it goes pear shaped at least I can sniff the tipex.

Nick

What flux are you using Nick? the HT5 or Tenacity No5 is better for big lumps as it stays lively for longer.

J

PS did you have a problem drilling out those holes?

Edited By JasonB on 21/11/2015 17:12:09

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Morning Jason.

Thanks for the advice. I shall order some Tenacity No.5 as you suggest. With this being the first silver soldering I have done I suppose I will not have the 'feel' of it totally. So a flux that stays in the zone longer will be of a good help.

The holes.? - I presume you mean because they do not look smooth in the bore.? They are. It's just that they have crud in them from dressing the rest of the webs.

I have had a mail from another member asking how I got rid of the tool machining marks. - I used a fine file, emery paper and a Dremil with the following abrasive in. :- **LINK**

Nick

No, I saw a photo you uploaded

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Ahhh. The drills made from blu-tack. Now I understand. (I think)

Nick

Hi Nick

Nice work to date; intrigued by the boring bar in one of your pics... any details, where from, size etc ?

George.

Nick if you have not silver soldered before then do a few test joints on some scrap, you have a lot of time invested in the crankshaft parts and it would be a shame to have a muck up with them.

Oh and get a move on, I have a video to upload once I can find some organ music to go with it

Edited By JasonB on 22/11/2015 10:59:58

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I like Bach.

Might scare the kids at the fair ground though.

Wow! I'm convinced I have some sort of musical dyslexia as I struggle to follow even simple tunes, but that made complete intuitive sense to me.

I have a marvellous old Russian stereo sample LP from the 60s that has a brilliant example of T&FinD on it, you can here the stops thumping in and out, and it makes the worlds shake! I also saw Sky performing it whiel Joh Williams was still with them.

If Bach had been alive today, I'm sure he would be into heavy metal.

Neil

Ello George,

It's an iscar one that I nabbed on ebay as 'new old stock'

The info stamped on the side says it's this one **LINK** Except it does not look like that one. Only similar.

Nick

Nick

That is fantastic ! ( In this case I mean the Bach - as well as your engineering progress of course!) I am very familiar with that Toccata and Fugue but the graphic gives a further indication of its complexity.

I have loved music, especially classical music, all my life but sadly never learned an instrument. A couple of years ago I decided to take some piano lessons so turned up weekly to torture the ears of a very nice lady teacher. She was very patient but I stopped after about a year - I realised that I was never going to pose a threat to Barenboim! I still tootle a bit each day and, with an electric piano and headphones, only I have to suffer!

Norman

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Did a test joint using the off cut surplus of the crankshaft I had turned and the waste from the parting off from making one of the webs.

Once done I but the crankshaft scrap stub in the lathe and made a few facing cuts. Then took some cuts off the diameter of 40 thou with 8 thou per rev feed to test it's strength. As you can see it held. Then rubbed on some emery to see the joint better.

These are the bits waiting for the flux that Jason recommended to arrive. As said I have taken quite a bit of time with these parts so if I make a dogs danglers of it I am going to dress in drag, joint the WI and take up jam making and flower arranging.

Nick

hi Nick,

why dont you loctite then pin the crankshaft joints? this is how virtually all miniature loco crankaxles are made these days.

cheers,

julian

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I am very tempted. ................. But that Jason guy-bloke has forbidden me.

Nick