Shortening screws

[John MCParticipant @johnmc39344]

[John MCParticipant @johnmc39344]

Many years ago I acquired a large quantity of 8BA screws, cheese and hex. head and varying lengths, probably a life times supply. As might be expected, they are never the right length! So I take the next longest, screw on a nut, cut it to length, then touch it on a fine grinding wheel to tidy up. This is fine when only a few need shortening but tedious for the 50+ I need for my next project.

Any ideas to make the job easier?

Thanks, John.

[Ian ParkinParticipant @ianparkin39383]

I have a set of pliers side cutters and they have screw cutting holes for m3.5 and m4 near the joint they work great if your screw fits in the holes

Shortest length is perhaps 8mm

[Mike ClarkeParticipant @mikeclarke87958]

Hi.

I shorten screws/bolts with a “nut plate”. Just a random bit of MS plate, drilled and tapped to suit screw. You can set required length with washers or spacers under head of screw. Cut off the excess with a hacksaw and then file flush with nut plate.

Mike

[Brian HParticipant @brianh50089]

Plus 1 for Mike Clarkes' method. When you've finished just store them away for future reuse.

Brian

[Matt HarringtonParticipant @mattharrington87221]

I use simple jig.

This one is a little better and easy to make on the lathe:

http://www.clickspringprojects.com/screwhead-holding-tool.html

Matt

[Martin KyteParticipant @martinkyte99762]

If you use a piercing saw the grinding op is not needed so that speeds things up a little.

regards Martin

[VicParticipant @vic]

I’ve made up some little threaded (M3, M4, M5, M6) jigs to trim down screws on the lathe. They screw in from the back and I then run the lathe in reverse to trim the screws.

[FMESParticipant @fmes]

One of these will crop them off square, **LINK** just a burr to clean off.

Sorry I couldn't find a UK pic

Regards

Lofty

[Speedy Builder5Participant @speedybuilder5]

Same question – different answers.

**LINK**

[Michael Cox 1Participant @michaelcox1]

Here are a couple of good methods from Rick Sparber:

http://rick.sparber.org/aubc.pdf

http://rick.sparber.org/BCF.pdf

He also has a simple jig for bevelling the ends of cut bolts:

http://rick.sparber.org/ubb.pdf

Mike

[Russell EberhardtParticipant @russelleberhardt48058]

I use a lantern chuck and a fine parting tool.

Russell

[Tractor manParticipant @tractorman]

I saw a design for a lantern chuck in M.E. I think.
Trying to think of a way to do batches of five or ten at a time but it involves making jigs etc.

[John MCParticipant @johnmc39344]

Many thanks for the replies. The root of the problem is not cutting the screw to length but tiding up the cut end so it will screw in to the mating thread. I like the ides of the of a "nut plate" as that will hold the screw while being cut and the end tidied up, unscrewing it through the plate will restore the thread.

Off to the workshop to make a nut plate.

John

[Alan Wood 4Participant @alanwood4]

Further ideas

**LINK**

[Matt HarringtonParticipant @mattharrington87221]

Thanks for posting Alan, I like simple approaches and the brass collars are just that.

Matt

[mechman48Participant @mechman48]

I have a couple of nut plates made from scrap aluminium to cover metric & imperial…. ugly as sin … but do the job.

George.

[Fowlers FuryParticipant @fowlersfury]

Re: " The root of the problem is not cutting the screw to length but tiding up the cut end so it will screw in to the mating thread"
Have searched for a current source of these without success.
I use the concave, diamond-impregnated surface of this "cutter" in a hi-speed mini drill then onto the end of a cut-off BA bolt. It produces a nice rounded end without damaging the leading threads in a few seconds. It's lasted for years – only wish I could find a new spare.

Addendum: Presumably the similar concave-shaped, but aluminium oxide stones which are freely available for mini-drills would be as effective although not as long lasting.

Edited By Fowlers Fury on 14/03/2018 12:27:24

[Grindstone CowboyParticipant @grindstonecowboy]

I like the idea of that diamond grinding cup, so a quick search found **LINK**

Not found anything in the UK yet, but they seem to be a fairly common jeweller's tool so will keep looking.

Rob

[Fowlers FuryParticipant @fowlersfury]

"…….so a quick search found.….."

Rob., well found !
However at 6mm D it's unlikely to fit the chuck of a hi-speed mini drill but mounted in a drill press it might do the job. Over the years, I've learned the best way to round the cut edge is to hold the mini drill in one hand and move the bolt with the other hand in a sort of 'conical way' inside the rotating concave (harder to describe than to do !).
If the bolt is held in the vice and the rotating cutter applied, the mini drill tends to jump about quite a bit.
Yet…..with drill press and vice it should be OK.

Prompted by your reference to a "jeweller's tool" – I'll also start searching.

[Steve CrowParticipant @stevecrow46066]

I made a primitive lantern chuck for small screws. The collets are for 12BA and M1.6.

[Philip RoweParticipant @philiprowe13116]

Posted by Steve Crow on 15/03/2018 13:40:08:

I made a primitive lantern chuck for small screws. The collets are for 12BA and M1.6.

Steve, that looks like a very useful lathe accessory – at least for the things that I do. One thing does puzzle me, it appears from the photos that the individual collets are not threaded, I would have thought that if they were it would give you more control over where the screw sits in the chuck, or am I seeing a problem that isn't really there?

Phil

[Tractor manParticipant @tractorman]

I don’t think the collets need to be threaded. As long as the screw sits snugly in the hole it will be central and is held in place by the threaded mandrel. Neat bit if work!

[Steve CrowParticipant @stevecrow46066]

Hi Philip, I did consider threading the collets and I would have made one if I needed lots of different lengths of screws.

However I needed a couple of dozen of the same length (3.5mm + 4.5mm) so I made collets to suit. I opened the holes with watchmakers broaches so it's a nice snug fit.

The holes in the front plate are witness holes. The plate is made from 1/32 ground flat stock with the centre hole bored (4mm) with the whole thing assembled to ensure it's true. I then hardened and tempered it and the holes make sure it goes back on the same.

The body was made fro an old M4 thumbscrew drilled and M6 tapped and the shaft is a sawn off M6 bolt.

It is a treat to use in the watchmakers lathe. It takes no time to saw to length then round and polish screw ends pre-blueing.

I'll make more collets as I need them – again take minutes to make with a hand graver.

Steve

[NimbleParticipant @nimble]

Use nut plate as described by mechman48 then cut off extended thread section with a cold chisel done properly the nut plate will clear up any slight burr.

Neil

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