bolt (m4 thread) cutting

[Fred]

Hello,

I bought a pair of those "crimping pliers", the ones that aren't recommended for crimping but which are supposed to also cut bolts. I bought this one:

have been trying to cut some M4 bolts (also from Tool Station). the problem is that I am not getting a clean cut and they are fouling the thread.

Is it because I have had bad batch; is it because I've bought the cheap Silver line brand; or is it that these are rubbish for all things including bolt cutting? Or could it be the cheap bolts?

Should I do a Dr D and use a hacksaw ;)

[Harry Bloomfield]

Fred wrote on 23/12/2009 :

> I have been trying to cut some M4 bolts (also from Tool Station). the

I have some similar ones which I only use for cropping bolts and they work fine - are you using them the right way?

You are supposed to screw the bolt into the thread, so once you have cut the bolt remains in the thread. You arrange it to cut off the unwanted tip rather than cut off the bolt. Unscrewing the bolt from the cutter then cleans up the thread.

[Usenet Nutter]

When you say "fouling the thread" I take it you mean making a mess of it as it cuts .have you tried spinning a nut on to the bolt to above the cutting point then cutting it and taking the nut off again after it is cut to see if that cleans up the thread .

I'm sure I have a pair of those that I have had for years for crimping electrics on old cars but wasn't aware that they could shear some bolts ...must look it out

[Dave Osborne]

No.

is it because I've bought the

No.

or is it that these are rubbish for all

Yes.

Or could it be the cheap bolts?

Probably wouldn't make any difference, except if the bolts were very tough, you would break your hand before they sheared.

Definitely. Then finish/chamfer the cut end with a file or a fine grinding wheel or a linisher.

[Mike Harrison]

Anyone know why the smallest on these is always M2.6 not 2.5 - I've never seen an M2.6 screw....

Useless for crimping.

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember Fred saying something like:

Bolt cutters? They barely do the job of crimping on s**te old cars. Bolt cutters, they ain't.

Yep. A junior hacksaw.

[Frank Erskine]

Or an angle grinder...

[Harry Bloomfield]

Usenet Nutter formulated the question :

There is an internal thread in the cutter, you screw the bolt/screw into that, cut it and then as you unscrew from the cutter it cleans the thread up. It helps, if after cutting you screw the bolt in , rather than out and run a file over the cut end, before trying to unscrew it.

Just see if there are a series of threaded holes near the pivot, with similar clearance holes in the opposite half.

[Dave Plowman (News)]

WD40 among tools. Does nothing properly. And just why would you want to shear bolts?

[DavidM]

A oscillating saw (eg Bosch PMF180) does quite neat job, specially on smaller bolts. A pair of pliers and the Bosch and zip, job done.

[Jules]

I normally do that. Put a nut on first, cut "gently but firmly" with cutting disc on AG, little light filing if needed, then back nut off to clean threads.

Never had a problem doing it that way, and it always seems quicker than using a hacksaw.

[Usenet Nutter]

But fewer sparks with a hacksaw unless you do it extremely quickly...lol

[Fred]

an M2.6 screw....

Thanks for the replies, if I may try to answer them all in this one post:

I am screwing the bolt into the cutters to the desired length and cutting off the excess with a smooth action but after cutting, the bolt doesn't look straight in the cutters; it's at a slight angle. I think it gets bent by the force of the cutting action. Mike says they are only good for brass above M3 and since this is M4 steel, perhaps this is why?

When I try to unscrew the bolt, there is some eccentricity as I can see the head wobble slightly from side to side as the screwdriver turns it. Once removed, there seems to be a small notch in the thread slightly above the cut; I guess at the point where the bolt is screwed into the cutters.

I tried the suggestion of putting a nut on but all that happened was the nut got stuck!

I shall be sending these back. I'm undecided whether to ask fro a replacement or a refund.

[Dave]

Not quite, you need to use a file at 45 degrees, around the diam of the thread, to remove the deformed thread that the cutter leaves behind on the bolt.

Dave

[Harry Bloomfield]

Dave Plowman (News) expressed precisely :

Have you tried holding onto a very short bolt, while you saw it?

[Usenet Nutter]

It's not easy as I have tried it quite a few times .I used to use a Mole grips to hold the head or sandwich the scrap part of the thread on a stable surface like a workbench or summat .

[Dave]

>>> I have been trying to cut some M4 bolts (also from Tool Station). the

Drill and tap a mild steel plate about 1/4 (adjust thicknes to what you need) by 2 by 3 inches, about 2/3 rds along one way towards the other 2 inch side. Make a saw cut to the tapped hole and screw the bolt into it with enough sticking out to be sawn off and put it into a vice so the screw is cramped by the squashed saw cut and saw off. Remove and clean up the end of the thread with a file to form a slight taper.

Dave

[Dave Plowman (News)]

[The Natural Philosopher]

There is an easy solution to this. spin a nut on. Grip the bit you DONT want in the vice, saw the bit you do off, with the nut, then unscrew the nut to re-form the thread.

Dremel is better than a saw actually, or an Angel Grinder.;-)

[mick]

or an Angel Grinder.;-)

Only at Christmas...