Shortening Screws

What method do you use? I ask as I’ve recently seen a Lantern Chuck again. I’ve never used or much like the idea of a screw plate. I prefer using the lathe. I currently use some little plugs tapped to size and held in a collet Chuck. I just wondered what other methods folks use?

Junior hacksaw normally, dependent on the screw size, screw a nut onto the thread first then cut and file unscrew the nut which will clean the odd deformed thread at the end of the screw. Larger bolts, lock two nuts on the bolt cut off the unwanted portion with a hacksaw in the vice, clean up the end in the lathe or file.

If you want a turned end, short of making a lantern-chuck:

The screw-collet of course should be longer than the lathe collet or chuck-jaws.

For screws finishing longer than the chuck jaws or collet depth, use a simple threaded collet in front of a spindle back-stop that bears on the screw-head.

If the finished screw will be shorter than the lathe collet or chuck, you could use a longer threaded collet whose back end is counter-drilled to clear the head, then tapped for a locking-screw that contacts the screw-head. Use a brass locking-screw, or a steel screw with brass or plastic slug, to avoid damage to the workpiece head.

I use my home-made Lantern chuck, works well and I can clean up the thread using a tailstock die-holder.

Thor

Very nice Thor, printed off ready to make!

I usually use the nut and junior hacksaw for small screws and bolts, I find large ones aren't so much of a problem...

used hacksaw and file for years but not anymore as i made the lantern chuck in MEW

Edited By martin haysom on 13/12/2021 11:58:01

Thanks for that Thor. It’s a much simpler design than others I’ve seen so I may make something similar.

For common thread sizes I use tapped lengths of square and hex bar held in the milling vice I have fixed at right angles to my jig-mounted 5-inch angle grinder.

The screw to be shortened is held captive inside the bar with a hex nut, which acts as both a guide/stop for where the cut is to be made and as a heat sink to reduce the chance of the screw being overheated during the cut.

It's a quick and accurate method requiring no lathe or special chuck.

Simple spacer, junior hacksaw, chuck the hex head screw in my hand drill gripped by the hex head, file and emery.

Tapped bit of hex brass (A/F > head size of course) slit lengthwise with junior hacksaw. Make sure the slit is between jaws on the 3-jaw, and clamp tight. Part off or face the length - light cutting forces, don't be greedy.

Jewelers piercing saw is the way to go for smaller sizes, no burr to speak of and looks quite tidy.

regards Martin

Have a look at this article: Model Engineer- N° 4480 (apr 2014) : Threaded collets

regards

J M

If your lathe can be used in reverse, mounting the screw from inside a threaded sleeve allows the excess to be parted off. I have an interal grooving tool that works for this. I just hold it in a three jaw chuck, which is adequate for most purposes.

Edited By Macolm on 13/12/2021 17:33:33

Edited By Macolm on 13/12/2021 17:34:17

Hi Vic'

One method of shortening screws is to screw on nut with excess length protruding, hold nut in vice and use a cold chisel to cut off excess length, unscrewing nut from screw will clean up thread.

Alternatively a cheap and cheerful “lantern chuck” can be made by turning down a short length of rod and threading the end, then using dome nuts in the three jaw drill and tap to the require size (head of screw must be able to enter), position screw to give length of screw required. Screw nut onto threaded shaft until head hits end of threaded portion, place in chuck and turn off unwanted portion of screw. Disassemble to remove screw.

I have done down to a 2mm screw.ic

My first attempt at a lantern chuck worked but not particularly well.

The Johnn Ashton design that won the John Stevenson Trophy is a much better device. It took a time to make all the carriers, but time well m,spent, to have a tool that holds the screw solidly and prevents it bending or backing away under cutting loads.

Howard