Heya!

New lad here so be gentle!

Imagine youve got an M20 bolt in front of you.... I need to make the last 30mm of the bolt a smaller size with no thread, so from the bolt head measuring down 30mm it needs to be M20 but below that it needs to be turned down to something like M14 with a domed end on the bolt.

Is there any advice anyone can give me on using a lathe? Only used one once and that was turning wood, not metal!

Thanks in advance!

SE

This is easy to do if you have experience with a metal lathe, but I believe a wood turning lathe is worlds apart!

There are some videos on youtube that might help-



For the dome at the end-



Although it would probably me much easier using a tool that is formed to the correct shape to create the dome.


If you just need the one making you are better off going to a local engineering firm and get them to do it for you- they might even let you watch from a distance

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DIY | Donnas dream house

Use a bolt that is MUCH longer than needed, clamp it thread-end in and do the required turning. USe a parting tool to cut to finished size.

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This post may contain nuts

The domed end complicates the job a little, assuming you have a fixed size bolt available...

If you have the kit the bolt could be spun between centres using a dog carrier:

http://bit.ly/ysJD2H

Most of the domed end could be turned then, preferably with a pre-shaped tool as mentioned above.

Alternatively, after turning the smaller diameter down between centres, put the hexagon end in the chuck and support the turned part with a "fixed steady" to permit greater access to the end for doming.

http://bit.ly/z6LE6q
If you can get a longer bolt, then Kelly's suggestion is less hassle....you could even shape the tool to dome the end AND part it off at the same time

wrinx

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www.ilmostro.co.uk

When you say M14 on the smaller diameter part, do you mean a thread of M14 or 14mm in diameter?

Would a chamfer be permissible on the end, rather than a dome?

wrinx

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www.ilmostro.co.uk

Have you got a lathe then? How long is the bolt. if its only short probably hold the head in the chuck okay for the whole job.
Probably easier to get it done by someone.

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Why isn't the number 11 pronounced onety one?

Lo!

Sorry about the long time in replying, totally forgot I signed up to this site until I looked in my bookmarks lol. Any way, here is a picture of what I managed to come up with in the end.

The finish isn't great as I'm not too bothered about it bearing in mind this tool is going to take a bashing.

That would have been a simple job, about five minutes on a hobby lathe :)

What's it for?

wrinx

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www.ilmostro.co.uk

Errrr... It's for this:


What you are looking at is the underside of a bogie on the Class 373 TMST train. Basically, no matter how big the crowbar or how strong the person using it is. You wont move that part. LOL.

Glad I asked now

wrinx

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www.ilmostro.co.uk

Basically the bolt is a tool to screw into the pin, to push it out of the hanger then?

Cant knock a wedge in above the top of it then....not much swinging room I suppose.
Less effort neede on a windy gun too i suppose

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Why isn't the number 11 pronounced onety one?

Talk about interference fit, this thing takes the p*ss!! Tried a wedge, cold chisel, heat, huge crowbar, the biggest guy we've got at the depot (he's MASSIVE).
Then noticed the M20 threads in the thing..

duuuuuuuh! LOL..

Hitch are you on mig-welding? You're name is familiar.

Cheers

Yeah, tha'll be me.

If its a regular job you do, might be worth getting a couple made up and sent off for case hardening.....?

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Why isn't the number 11 pronounced onety one?

Ah very good sir!

It's not really a regular job that we do, haven't actually had to use it as of yet. Wouldn't mind getting them sent away for hardening though. Before I do that I want to see how well they work first lol.