How to chuck a bolt head

[Philip HardyParticipant @philiphardy41757]

Whilst it may sound a straightforward question, I need to turn down 40cm off the end of a high tensile bolt for a project in y Myford ML7. Does anyone have a ny tips on how to set up the hex bolt in the jaws so that I can machine the end of the bolt

[Philip HardyParticipant @philiphardy41757]

Help and suggestions

[Grindstone CowboyParticipant @grindstonecowboy]

I always put a couple of nuts on the bolt – same size as the head, obviously, so there's no tendency for it to tip. They don't have to be tightened up, just get the flats aligned. Of course, this depend whether the finished length you are aiming for will allow for this.

Rob

[Clive FosterParticipant @clivefoster55965]

Normal good practice is to use a sleeve on the bolt large enough to give clearance to the head and, hopefully, long enough for the chuck jaws to get a decently parallel grip.

Easier with fully threaded machine screws where an internally threaded sleeve can go right up to the head but a partially threaded, partial clearance drilled one works as well on a proper bolt with a pain portion of shank below the head.

Long joining nuts work well enough at this too should you have some. (I keep a small stock of the sizes Screwfix supply 'cos they are handy for oddball stuff and fixtures.). Or just lock a few nuts tigether. May take a bit of a heave to get the flats lined up after tightening but most are surprisingly good.

If the bolt is long enough or your chuck jaws shallow enough just grab the shank and be done with it.

I've been known to just grab the thread and be done with it when "get-er-done" trumps Inspector Meticulous.

Clive

Edited By Clive Foster on 22/09/2022 23:03:03

[Nigel Graham 2Participant @nigelgraham2]

I've often used stacked nuts as Clive suggests, but sometimes you can align them without undue force by judicious waggling around.

If the bolts is long and you need turn an appreciable length of it, it's worth holding it as close in possible to centre the end, then supporting that from the tailstock when its withdrawn to the working distance. (Assuming a centre-drill hole won't affect the bolt's intended purpose.)

[John HinkleyParticipant @johnhinkley26699]

40cm! That's a lot to take off a high tensile bolt. If I had one, I think I would remove the majority of it with an angle grinder and then clean up the end in the normal way.

John

[peak4Participant @peak4]

It would help if you gave us the before and after sizes, both length and diameter.
Also, do you really mean a bolt, a screw or an Allen headed cap-screw etc.

Bill

[Peter Cook 6Participant @petercook6]

If you are simply shortening the bolt by 40mm, I would saw off most of it, and clean up the end to length on the belt sander.

The proper way of course is to use a lantern chuck.

Edited By Peter Cook 6 on 23/09/2022 00:05:55

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Peter Cook 6 on 23/09/2022 00:03:22:

If you are simply shortening the bolt by 40mm, I would saw off most of it, and clean up the end to length on the belt sander.

.

I am just wondering where exactly the ‘typo’ is …

Philip actually wrote: I need to turn down 40cm off the end of a high tensile bolt …

so did he mean: I need to turn down 40cm of the end of a high tensile bolt …

Dunno !

MichaelG.

[JasonBModerator @jasonb]

If it's a big bolt then just hold by the hex head in the 3-jaw and use a fixed steady at the other end set far enough in to allow you to work on the hopefully 40mm .

[Roderick JenkinsParticipant @roderickjenkins93242]

Hold the threaded end in the drill chuck in the tailstock, introduce the head into the 3 jaw chuck, tighten this, loosen the drill chuck and slide the tail stock out of the way.

[Eric TomlinsonParticipant @erictomlinson95346]

Hold the threaded end in the 3 Jaw and part off the desired length.

[Philip HardyParticipant @philiphardy41757]

Thanks guys, great ideas. Just to confirm Im looking to turn down a 40cm length of the bolt's thread as I'm making a puller that the end needs to fit into a shaft hole.

[CirclipParticipant @circlip]

Good ole dressmakers sizes again, 40cm =400mm= 15 3/4"

Regards Ian.

[Philip HardyParticipant @philiphardy41757]

Should read 15cm

[DMBParticipant @dmb]

I would go with MichaelG s suggestion, take off bulk with the angle grinder then clean up on coarse bench grinder wheel and finish, if needed on belt sander. I would add that start off measuring, black marker pen, hold with pliers or molegrips, if large diameter and introduce it to the angle grinder. Anything over say 1/4" / 6mm diameter.

As Peter Cook6 said, anything special, use a lantern chuck.

I have just one slotted cheesehead 5/16" BSF X 3/8" long screw to make. This is how I plan to do it. Chuck round bar and turn down to overall thread diameter less 2 thou and use t/s dieholder. Part off. Drill remaining bar 1/2" deep and tap it. Screw in embryo screw fairly tight, part off bar about 5/8" from the end. Set up on a thin parallel in mill vice with head projecting from the side. Slitting saw in drill chuck, set up on Centreline of screw and to slot depth. Can probably do it in less time than it's taken me to type this. Others will probably say why not go out to nut and bolt store but I want to do this myself. If I had a lot to do, I would use a slightly different method, if specials but a common size, I would buy in. I also need 2 X 2BA slotted cheeseheads for another project, make same way.

[Nigel Graham 2Participant @nigelgraham2]

Ah – thank you Philip. That extra information helps!

Merely holding it by the head alone is NOT a good idea especially when as seems, you need a lot of bolt protruding from the head.. Apart from being unlikely to hold the bolt parallel to the axis, it provides insufficient length of grip and the pressure of the tool will push it out of line, possibly damaging it and the tool.

(How do I know? Guess!)

That length though. Surely not 40 cm but 40mm? For we of inch-age that's roughly 16 inches to 1-5/8 inch!

i would not use Jason's suggestion of supporting any threaded material by a fixed steady. It will provide support but unless a roller-steady, it won't do the steady's bearing surfaces any good.

Parting-off threaded material is of course feasible but I would advise using minimum projection of blade from holder and a very careful feed (without rubbing). The thread will try to bend the parting-tool, risking it digging in or even breaking..

I would simply saw the bolt to length then face the end – or if an accurate end is not necessary, file it to remove the sharp edge.

.

However I read your post from the start as turning a length of the bolt down to a smaller diameter, with a properly-faced end.

So for that I would use the holding method described earlier (a simple collet or a pair of lock-nuts for maximum holding length), and tailstock centre for support.

[not done it yetParticipant @notdoneityet]

Non comprendez. What exactly are you trying to pull? I think you are trying hard to make things difficult for replies and actually doing the job.

The sensible way would be to cut a centre and support with a tailstock centre?

Edited By not done it yet on 23/09/2022 11:19:07

[MadMikeParticipant @madmike]

I am with NDIY here. just what are you trying to make? A sketch with dimensions would be of great help to the gathered throng.

However with the limited/inaccurate information available I think you are all approaching this from the wrong direction. Chucking a bolt head, use of an angle grinder etc etc? Really? I would simply get a length of hexagon bar, turn down the end to size, the reduce the diameter along itds length and simply cut the desired thread. Then reverse the bar and part off to length.

So, Philip Hardy, a sketch please in case I missed something.

[Philip HardyParticipant @philiphardy41757]

The bolt is part of a puller to remove a clutch assembly on a lawn mower, I'll post a photo of it later

[Philip HardyParticipant @philiphardy41757]

here's the link showing the tool I am looking to replace the bolt

https://www.ebay.co.uk/itm/275427388958?hash=item4020c06e1e:g:nFcAAOSw2~ZbxkVq&amdata=enc%3AAQAHAAAAoPnmauL7EoHKszkqyYnGk%2FV1a3DpU2KwDS8xPRHD4cJSnXKvwdvkb1cqDEDvax3GHgxS%2FEk7ao3zrhxhTe6xgwAuyElOVA%2FsaSUktZxy6E9vgiYuX1mpYZQznFCJJw60cmw8PcoPxOs4HaetihVeGXFaN%2BTrF25dHY6%2FQ98nVIcfZM9Yym9q5HTkzkr%2FpcZw7ckv14sL%2FW1SLIvqxREtaGc%3D%7Ctkp%3ABk9SR4L3jJ7tYA

[Tony Pratt 1Participant @tonypratt1]

Posted by not done it yet on 23/09/2022 11:11:01:

Non comprendez. What exactly are you trying to pull? I think you are trying hard to make things difficult for replies and actually doing the job.

The sensible way would be to cut a centre and support with a tailstock centre?

Edited By not done it yet on 23/09/2022 11:19:07

Go with NDIY, 'cut a centre and support with a tailstock centre' or hold the thread in a bush or collet and cut plain diameter.

Tony

[peak4Participant @peak4]

Posted by Philip Hardy on 23/09/2022 09:35:59:

Should read 15cm

Which bit should read 15cm, the overall bolt length or the turned down section?
What thread is it; looks to be M10 or M12.

On the Myford, I'd probably hold the head in the 3 jaw and use tailstock support, as we're not bothered about perfect concentricity for this one (use the 4 jaw if you are).
If you have a fixed steady, maybe turn down a plain nut to a round threaded tube, then using a second nut, lock it onto the thread.
The round nut you've just turned down will run in the fixed steady and allow accurate centre drilling.
If you really do need a 6" (15cm=150mm) turned down section, leave the steady there and use it as well as the running centre in the tailstock.

Bill
Bill

[Nigel Graham 2Participant @nigelgraham2]

NDIY –

That's worded a bit unkindly. Philip has asked under "Beginners' Questions", what to many of us might be a simple problem, but perhaps in consequence has not realised we need better information to help him.

Including that matter of the 40 cm??

Philip –

I think what you are asking is basically simple but the differing replies suggest we've not all grasped what you are making, because I am afraid you've not given sufficient information.

It's best with a question like this to give a dimensioned sketch. It does not need be a proper engineering drawing to ISO-umptyone for something like this. Just a photo of a simple sketch on plain paper.

In particular here: if I am right about your intention, which is to turn the end of an ordinary bolt down to form a long spigot. You need verify the units (I don't believe 40 centimetres as that would call for a fabrication not a modified bolt), the diameter and length of the stock bolt, and the diameter and length of the turned section.

In which case your question should read something this, and I'm assuming you are working in metric:

'

I need turn the end of a standard [insert designation] hexagon-headed, high-tensile bolt down to x mm for y mm length, to form a spigot that fits a hole down the end of a shaft; as part of a special puller.

How do I grip the bolt in the chuck and support the outer end?

.

That alone ought suffice, even without a sketch; and I and no doubt others would have replied, as I have above:

Put the bolt as far back in the chuck as possible, gripped by a split-collet or lock-nuts; centre-drill the tip; draw the bolt out sufficiently far but still gripped for as much length as possible, and support it with a tailstock centre.

You may need use a half-centre for tool access, and even then, as an ML7 owner myself, I'd say you'd probably also need swing the top-slide back at an angle to clear the tailstock, and then use the rack feed. Or lead-screw if your lathe has a graduated lead-screw handle.

My lathe does have a lead-screw dial, but I don't use it very often. If the spigot length is not critical I usually move the tool along with the lathe switched off, to rule measurement, switch the machine on and make a light cut there as a marker. The finished length is usually easy enough to bring within tolerance.

[Philip HardyParticipant @philiphardy41757]

Thank you Nigel, I was a bit concerned my question was worded incorrectly which attracted comments.

I have a high tensile bolt that is 15cm long and need to reduce the bolt down in size for 4cm from the end to enable it to fit through a hole in a clutch assembly.

I added a link to the thread which shows the puller.

I will take a photo of the bolt placed next to the one I am trying to replace and paste it here

[Author]

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