Postman Cometh Part 2

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Just so you all know I have not been slacking.

Still need to dress and finish the webs properly. If I cannot get a decent finish on them I will cheat and paint them.

Nick

Looking good, now don't spend all your time twirling the flywheel round, get on and finish the rest

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Ehhh. ........................... You mean it's supposed to turn.??

Oh dear.!

Nick

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Is this a chilled casting.???

Nothing will put a cut onto the outer corners. Crobalt tool or carbide inserts just get wrecked.

Cheers, Nick

Edited By Nick_G on 06/12/2015 13:05:49

Yes

Get your blowlamp out and heat it to bright red and hold it there for about 15mins then allow to cool as slowly as possible. Should then be able to machine it. I would mill with indexable carbide if you have it but the holes should be OK with a HSS drill as they are in from the corners.

Alternative if you have an open fire or woodburner put it in there for the night (you will need a lit fire) and leave to cool in the ashes overnight.

J

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Cheers Jason. It's cooling.

I will try again in a bit.

Nick

This is where a pair of night store heater bricks come in handy because they retain heat. Warm up one brick, cook your part on the other brick then place the first brick on top. Your Celcon-style brick won't retain the heat and you may still end up with chilled edges.

Regards, Steve

I had to do something similar with a brake shaft bracket that I couldn't machine. I heated it up to bright red, held it for a while then wrapped it in some ceramic insulation - It was still cooling down about 8 hours later, but it machined lovely the next day!

Edited By Exmoor309 on 06/12/2015 23:15:54

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About time I made the engine taller, so onto the cylinder.

I know there are several ways to do a cylinder but chose to use a 4 jaw. So after checking overall 'trueness' I set up the best aproximation to the bore.

Then faced off using the distance between the cast inlet ports as a long center. A compromise had to be taken as this would have left the point of inlet into the cylinder uneven due to the steam passage casting to being even.

Casting was reversed and reset with a parallel behind the already machined face and the chuck face. The bar and a dial indicator was used for best guesstimate of the bore center.

Machining to the other face and the bore proceeded.

Short clip of video.

I am happy with the result.

Then over to the mill to face off the ports.

Used the 'button' tool in the fly cutter again to do this.

Last time I used this tool in the mill it caused some interest to how it performed. So here is a short video of some quick roughing cuts. (forgive the wobble as I am holding camera with one hand and cranking with the other.)

I have used a 6mm button tool in the same way for long parts in stainless steel where possible wear of a HSS tool would have been unacceptable. The part was curved but with an average width of about 30mm and had six Ø20 holes in it. the button tool worked well and had no issues with the interrupted cutting required.

Martin

The sound from that fly-cutter tells you it's working a treat, typical of cast iron.

Emgee

Neat fly cutting! Any ideas about who sells the tool and inserts?

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I got it (I think) from Chronos. **LINK** The one I have is a Glanze listed as XC40 due to the fly cutter taking an 8mm toolbit. Yours may of course be a different size.

When the insert loses it's edge, just rotate it a few degrees and you have a different new cutting edge. They seem to last quite a while.

Hope this helps, Nick

Edited By Nick_G on 09/12/2015 19:21:57

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Progressing on with the valve chest.

Nick

Lovely finish on the bore Nick, was that using your posh boring bar you were telling me about the other evening?

Martin.

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lol yeahh.

It's as they say a cracker. - There is noway as a hobbyist that I could have afforded or justified buying one at retail though. I was just lucky in being in the right place at the right time.

Nick

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Time to mount the valve chest and it's cover to the cylinder.

Semi tacked the bits together using super glue. (a useful trick learned on this forum) and clamped them square into the vice.

Then used and edge finger to locate the center of the chest.

The DRO was then used to navigate around the holes and to drill their depth. Tapping size first then clearance size in the cover and chest leaving the cylinder section still at tapping size.

A blip with the blow lamp to brake the super glue bond, tap the cylinder threads and a dressing to the lid face. .......... Voila.!

Nick

Edited By Nick_G on 11/12/2015 02:31:09

Coming along very nicely Nick; I like the finish on the bore. I have 3 Stuart kits to get cracking on with in the new year.

George.

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Hi George,

Many thanks. Which kits have you got and which one are you planning first.?

Nick

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Ready for a weekends machining. Then find out I have not got some of the drills, taps, dies etc. I need.

Numptie bu33er I am.!

Like this valve rod that needs a 4 BA thread on it. Turn it to size to find out that I don't have the die that size that I 'thought' I did.

Paaahh, Nick