You mean turning square bar?

It won't cause a problem if you take modest cuts. You'll soon get a feel for it.

> what i need to know is am i better running file over corners to rd of slightly so i don't damage cutter or won't it matter?

What Jason & Capstan say, chipping the very corner off puts minimal load on the lathe, In fact the biggest loads seem to come at about half way through the corner when the length of cut is enough to slow the lathe down a bit and the gap before the next cut is enough for it to speed up a bit more.

If you can use tailstock support to make sure it flexes as little as possible

If you can vary the speed this can help reduce any 'clunks' if not reduce the cut and keep the feedrate modest.

Neil

Nothing silly about that Martin, it is a perfectly valid approach and in my view the easier option. It also allows the square to be formed just nicely within the original bar diameter to leave a witness of the shape on the corners.

It does of course mean choosing a bar size which will give the across corners dimension required on the finished bolt.

Regards

Brian

Hello Neil,

I don't agree completely with you; forming the shank of the bolt has the same degree of swarf generating in either stock form, but I do agree with you over the second machining stage needed to square the head from round bar.

I still think the round bar route is easier than lumping off a length of square to form the shank of the bolt

Brian

Put like that Neil I have to plead insanity, that's the second time this week I've been shot down in flames!!

Oh dear, is this early onset senility? Time to hide in my box I think. Please gloss over my comments everyone.

Brian

A while back I had to make one, I used a nice high tensile bolt. I turned down the head leaving a step and silver soldered it into a square. After a good clean up with the wire wheel it looked fine and the hardened bolt thread did not wear as was the case with the old Mild steel one. It got a lot of use.

Regards
John

Brian,

I would still go the round bar route, no intermittent cutting and no wasted time clocking a square bar true, machine four sides could be done quicker.

Martin P

Your more likely to get chipped carbide tooling doing that sort of thing if the headstock bearings are loose. If your using HSS there is unlikely to be a problem.

Best option to minimise strain in a number of places is to use a slow speed and fine feed to rough it out. I've been known to turn with the back gear in but that's probably a bit extreme for this sort of thing but why not really. Assuming you have the gearbox you can go down to 1.5 thou per rev and also take a decent sized cut. That's 224 tpi setting if your on change wheels. Personally I feel the worst thing to do with work like this is to be ultra cautious. In this case that means more bangs as the things turn round. I'd take cuts of my usual size, get it over as soon as possible and not worry about it.

From round or square? If you need to mill to get the correct square you may as well work from round. If you would need to do a bit of filing from square and no miller square would be the easiest option for a lot of people.

You could also fabricate from all thread and use loctite. I've also seen that done with out. Screw the all thread into the square , file or what ever flush and dot punch around the thread. That does need fairly well mated threads. You could also make the bits for doing that yourself. Probably a good idea if you have reasonable taps and dies. Loctite could still be used but let it set before filing or machining flush and then dot punching.

John

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Edited By John W1 on 24/06/2015 19:21:41

What's great about being a novice is that you can crack on happily making round things square, square things round and not realise you did wrong until you start reading the ME forum posts!

Steve

What you did not google "Southbend steady" to see what the screws are like

It's the ones on the left. So the allthread fabricated method is not going to work in this case.

Edited By JasonB on 24/06/2015 20:40:08

I just knock the corners off with angle grinder, outside of course, with visor , oh and someone with a suitable extinguisher.

I'd probably take those down in one cut apart from a bit left to finish. Slow speed and a fine feed. Witha centre in the end by the look of them.

John

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Edited By John W1 on 24/06/2015 22:23:27