Advice please- machining Sweet Pea loco cylinders

[Nick TParticipant @nickt]

Hi All. I am just about to start machining the faces of the expensive cylinder castings for my 5" gauge Sweet Pea steam loco. The book suggests fly cutting on the lathe but as I have a Tom Senior Vertical Light mill I would rather use that.

Would one of these 25mm carbide tipped tools be OK for the job? Any help and advice would be most welcome.

Thanks, Nick

 

Edited By Nick T on 22/07/2017 10:50:07

[Nick TParticipant @nickt]

[Nigel BennettParticipant @nigelbennett69913]

To use a 25mm insert-tool cutter like you show, the milling machine needs to be good and rigid, and the job well clamped down. Your Senior milling machine isn't above suspicion in that regard. I think I'd probably use something like a 12mm solid carbide cutter. You'll need an ER collet or similar to hold it.

One ray of hope. I have one spare unmachined Sweet Pea cylinder so if it goes all pear-shaped for you on one of yours, then you can have it for the cost of the postage.

Good luck!

[Nick TParticipant @nickt]

Thanks Nigel for the information and thank you also for the offer of a casting if it all goes pear shaped – it is much appreciated. How did you machine yours? Nick

[Nigel BennettParticipant @nigelbennett69913]

'Twas a while ago; I've just delved into my old photo album to find it…

I skimmed the bolting face flat with a 12mm carbide cutter in the milling machine (Rishton VM60; same sort of size as yours). The cylinder was then mounted on the lathe cross-slide, sitting on the bolting face with a packer underneath of the correct thickness. A between-centres boring bar then brought the bore to size. I used a lathe tool held in a four-jaw chuck as a fly-cutter and skimmed the end face. The casting was then swung round and carefully angled (NB mine is for "Edward Thomas" but uses the same castings) and the port face fly-cut using the lathe tool again. Then back on to the milling machine to do the ports.

If you need, PM me your email address, and I'll photograph the photos (good old silver halide technology then!) and email them to you. There are just five photos.

Cheers

Nigel

[Nick_GParticipant @nick_g]

.

Why not use a fly cutter in the mill you have.? – That way it's done on one sweep of the tool.

I have had very nice results on cast iron doing such on both cylinder port faces and bed castings.

I have also found using this type of tool works very well in a fly cutter upon cast iron.

Nick

[Nick TParticipant @nickt]

Thank you Nick for the information – I hadn't see that type of tool. I have PM'd you Nigel.

Regards, Nick

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