Shortening a screw

[Andrew Pitonyak]

I decided that I wanted a small chest of drawers to hold some tools. I had little time, so I created my drawers out of ½" plywood. The screws with the knobs and pulls that I had on hand were 1" long. For my knobs, the screws were about 1/16" too long, so I used a small washer. For the pulls, however, the screws were about ¼" too long; too much to just use washers. Although I have a stash of longer screws, I did not have any shorter screws that would work with the pulls.

My problems:

1. How to hold the screw while cutting?
2. How to mark where to cut?
3. How to cut?
4. How to clean the threads after cutting?

The screw head is larger than the screw, so, I needed a way to hold the screw in my wood vice. I took two small scrap pieces of ½" plywood.

I laid the screw on a piece of scrap plywood and I used my Paolini Pocket Rule to set the screw so that it had a bit more than ¼" sticking out the end (see http://www.woodpeck.com/paolini.html); you can use any ruler.

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Place the second scrap piece on top of the screw.

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The scraps are wide enough that they are wider than the screw head so I can place this into my vice. It is easy to pick up the screw and hold it with one hand. If you need to change how far the screw sticks out, turn the screw and the threads will move it in or out. The threads cut into the soft plywood holding the screw in place.

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Here is the screw in my vice. Not a very interesting picture, but, it gets the point across.

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It is easy to verify that the measurement is correct before you cut. Here I check the height while the screw is in my vice waiting to be cut.

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Although I own a couple of power tools that could easily cut the screw, my hacksaw was readily available and makes short work of the screw. I use scrap wood as a measure so I know where to cut. When I cut straight through from one side to the other, I had a small lip sticking up on one side of the screw. In this picture, you can see that I cut a bit from all around the screw rather so that I would not get a lip on the side that I had to take down with a file.

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This is the messy edge on the end of the screw after I cut the end. A couple of things to note. First, there is a slight raised section in the center of the screw. I could file that down if I wanted to, but, for this application it does not matter. If you look carefully, you can see actual cut marks where I cut in from multiple sides. You can likely also see that the threads are usable all the way around.

Usually, I would place a nut on the screw to clean the threads after I cut it, but, I did not have a nut to do this.

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Finally, here is the modified screw next to an unmodified screw.

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[Jerry Wright]

Pliers and Bench Grinder.

[Matt Day]

Very elegant solution to a very simple problem.

I'd use a vise with wooden jaws and a hacksaw and clean up on the grinder if it was a big cut, or just grinder like said above.

That's a bolt by the way if I'm not mistaken.

Screw a nut on the bolt so after you cut the bolt, unthreading the nut chases the threads.

[Bernie May]

thread a nut on bolt. Hold nut in vice. Cut bolt. Unscrew nut to clean threads.

[HANK METZ]

I use a pair of terminal crimper pliers, most have thread cutters that can chop 4-40, 6-32, 8-32, 10-24, 10-32 thread screws of mild steel. Most pulls and handles use either an 8-32 thread or they may be metric- in which case you're on your own.

[Lee Schierer]

I use a pair of terminal crimper pliers, most have thread cutters that can chop 4-40, 6-32, 8-32, 10-24, 10-32 thread screws of mild steel. Most pulls and handles use either an 8-32 thread or they may be metric- in which case you're on your own.

That's what I use when the screws are small For larger sizes I use a double nut tightened just above the length I need, then I cut is with a hack saw and file the end before removing the two nuts, which clean up any damaged threads.

[Andrew Pitonyak]

I'd use a vise with wooden jaws and a hacksaw and clean up on the grinder if it was a big cut, or just grinder like said above.

Could not just use a wooden vice because the head was would hit the sides and it was not long enough to protrude below the jaws.

That's a bolt by the way if I'm not mistaken.

No idea, but, it does have a "screw" head.

Screw a nut on the bolt so after you cut the bolt, unthreading the nut chases the threads.

Usually do, but I did not have any nuts for that size thread; sadly!

[Andrew Pitonyak]

Yeah, I have used those for thinner screws. No idea what the thread was on those screws; I know that some of them are a strange size. Never knew why they had such uncomfortable handles on those things.

[johnny means]

The real lesson here, if your going to stick with this woodworking thing, invest in a small collection of odds and ends hardware.

[David Hawxhurst]

use a lathe and a cutoff the excess (part off) then fill at 45 degrees on the lathe, works for me.

[Peter Quinn]

I keep a pair of Klein wire strippers in my installers box with some comfortable handles and a good mechanical advantage just for this purpose, handles up to 10-24. That and a little belt sanding to chamfer the lead in works wonders. I also have a metric pair. Hard to tell in the photo but those screws look a little fatter than 10-32, looks like a good method you've developed there. We have a boc of breakaway screws in the shop for those occasional odd needs, they have perforations that allow you to pick multiple lengths and shorten them up on the fly.

[Ronald Blue]

use a lathe and a cutoff the excess (part off) then fill at 45 degrees on the lathe, works for me.

Why 45 degrees? The thread is 30 degrees on each side.

Wire strippers/crimpers are the hot setup. However don't buy the cheapest pair you can find unless they happen to be Klein or something comparable.

[Andrew Pitonyak]

I have seen the breakaway screws a few times. I should purchase some for just such occasions. It expect that it would be less important if I was more of a production shop since then I would be generally making things the same... and I definitely do not do that.

[Keith Weber]

I've done this in a pinch when it's Sunday night and the hardware store is closed, or when I figure that it's not worth the drive. I use my vertical belt sander. First, I thread on a nut to keep the screw level on the table and to aid in hanging onto it by hand.

I like the belt sander better than a grinding wheel because you can change grits in seconds, the belts are generally smoother, and you have a flat platen for a nice, square cut. It just takes seconds and it doesn't mess up the threads like a hacksaw blade or a coarse grinding wheel. Just have a little cup of water standing by for occasional dipping, because the bolt can get hot if you prolong the cut. It works equally well on larger bolts.

I usually put a little chamfer on the end of the thread to aid in starting (by hand spinning with a very, very light touch on the belt. Works like a charm!

[Jim Matthews]

thread a nut on bolt. Hold nut in vice. Cut bolt. Unscrew nut to clean threads.

+1 on this.
Same way I was taught.

A little filing before running off the nut, to ease the burr.