# How Do I Trim Ss Screws Accurately And Cleanly?



## angelfj1 (Jan 6, 2016)

I never seem to have the right length screws and bolts.  When working with mild steel or brass screws, I use my electrical strippers.  They have a provision where you thread in the screw you want to cut and the tool makes a clean shear cut.  When you back out the remaining screw the tool reforms the threads that may have been damaged.  With a little clean up I'm usually good to go.

So, I had 4 -  10-32 x 1.25  SS  socket head screws that had to be shortened by approx. .25".  I tried the stripping pliers, but the SS was too tough and I did not want to damage the tool.  I did not have a convenient way to hold these screws in my mill vise and same thing with my lathe.

So, what is the best way to trim SS screws and bolts that results in an accurate and clean cut?

Thanks, Frank


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## Dan_S (Jan 6, 2016)

When I need to trim screws to length of any type, I do it in the lathe. 


chuck up some scrap that has been turned round and face both ends

trim it to the appropriate to length

drill and tap it for the bolt size in question

pull the stock and thread the screw in, and lock it in place with a jam nut
remount it, and face/turn the bolt to length.
an optional step is to chamfer the end


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## planeflyer21 (Jan 6, 2016)

Depending on the tools at hand, I use either a Dremel with a cutoff blade or grind it down on a wheel or sander.  Threads can then be cleaned up with a knife-edged small file.


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## wawoodman (Jan 6, 2016)

Tap a through hole in some steel plate. Thread your bolt through it to the proper length, and dremel or grind off the extended piece. When you back it out, it should straighten the threads, just like the electical pliers.


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## bill stupak (Jan 6, 2016)

Here is what I use

http://www.hobby-machinist.com/posts/313484/

You could also just make up a piece of angle with various sized tapped holes and use a cut off blade or hacksaw.

Bill


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## Ed ke6bnl (Jan 6, 2016)

bill stupak said:


> Here is what I use
> 
> http://www.hobby-machinist.com/posts/313484/
> 
> ...



That is the tool I made and have all common sizes on the angle iron to cut with bandsaw, chopsaw, or sand grind to size/


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## Fabrickator (Jan 6, 2016)

wawoodman said:


> Tap a through hole in some steel plate. Thread your bolt through it to the proper length, and dremel or grind off the extended piece. When you back it out, it should straighten the threads, just like the electical pliers.



This is what I do. I made a 3/8" x  8" steel plate with multiple, common size, tapped holes and then heat treat. One side is SAE and the other is Metric.  You need a pretty clean cut (deburred) so you don't screw up the jig.


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## John Hasler (Jan 6, 2016)

planeflyer21 said:


> Depending on the tools at hand, I use either a Dremel with a cutoff blade or grind it down on a wheel or sander.  Threads can then be cleaned up with a knife-edged small file.


Put a nut on it first.  When you back the nut off it will clean up the threads (or be fancy and put a die on it first).  I often just use the grinder to bevel the end a bit.


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## joshua43214 (Jan 6, 2016)

I just saw the screw off and grind the end to clean up the threads. With small screws, I either hold the screw in visegrips or put it on the end of the appropriate driver. I angle the screw down slightly, with it held straight out from the wheel, and roll the screw as I grind it.
Takes only a moment and cleans up the threads and puts a nice chamfer on it at the same time.


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## Paul in OKC (Jan 6, 2016)

Second on using a nut. Screw it on past length, cut off, back the nut off. Works very well on most screws.


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## rgray (Jan 6, 2016)

Here's an old thread with lots of ideas:
http://www.hobby-machinist.com/threads/how-do-you-cut-screws-to-the-proper-length.31267/


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## kingmt01 (Jan 6, 2016)

It depends on what I'm standing closer to & what size bolt it is. Something the size of a 10-32 I usually just try to snap it off. If you have a through hole in a plate you can screw it in then smack the unwanted portion sideways with a hammer. If you will never have to mess with it again just start it carefully & forget about it but if you will be removing it & putting it back often then dress the end so it is round & tapered to start easy.

Sometimes two nuts locked then grab the nuts & unwanted part of the bolt with vice grips & snapping it off. Dress the end as needed.

Two nuts on it to line it up in the chuck & face it off or use a hack saw to cut it off. Dress as needed. This is the easiest/fastest way to dress it as well.

Put a nut on it then grind it off.

After seeing Bill's jig I believe I'll add one of those to the project list as well.


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## PatMiles (Jan 17, 2016)

How about a 10-32 die with the screw in it. Position the slot in the die between the chuck jaws so when the chuck is tightened the die clamps down on the screw so it does not move. A caliper can be used between the chuck jaws to measure the screw as it is being trimmed. Small fine file to clean up and round over the fresh cut.


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## BGHansen (Jan 17, 2016)

Dan_S said:


> When I need to trim screws to length of any type, I do it in the lathe.
> 
> 
> chuck up some scrap that has been turned round and face both ends
> ...


I collect Erector sets and a commonly missing part in sets from 1913 - 1923 is a 1 3/8" 8-32 screw.  I use Dan's method with stainless screws (look very close to the original nickel-plated screws).  The "meat" of an article I wrote for the ACGHS newsletter (www.acghs.org) is attached.  Works pretty well with a chunk of steel.  

An alternate method was a block of wood and T-nut (pictured in the attachment).  Drill the clearance hole for the T-nut and pound it in.  Then rip the board with the T-nut up against the fence to get the proper length.  Insert the screw and grind away.  When the T-nut starts thinning out (if you hit the wheel or belt), pound it out and use a new one.

Bruce


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## angelfj1 (Jan 17, 2016)

PatMiles said:


> How about a 10-32 die with the screw in it. Position the slot in the die between the chuck jaws so when the chuck is tightened the die clamps down on the screw so it does not move. A caliper can be used between the chuck jaws to measure the screw as it is being trimmed. Small fine file to clean up and round over the fresh cut.




great idea - thanks


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## Wreck™Wreck (Jan 17, 2016)

Make a screw holder for the lathe like so.
If a RH thread part and chamfer from the backside with the spindle run in reverse so as not to unscrew the parts. If a LH thread run it in the forward spindle direction for the same reason.
The shoulder is for aligning the fixture in the chuck jaws and maintaining accurate Z position, so set carriage stops. Piece of cake.
If you make 2 screw holders one will be running whilst you are changing parts in the second.


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## KMoffett (Jan 17, 2016)

For shortening a few socket head cap screws I too use a Dremel with the red cutoff disks. Put two nuts on the screw. The outer one with the outer face at the point where to make the cut.  The inner one used as a jam nut, to keep the outer one from spinning as during the cut. Clamp the head in vise-grips or vise. Use the outer nut as a fence the guide the cut. After cut ting the screw, remove the outer nut. Then chuck the screw head in a battery drill. Set the rotation so the nut doesn't spin off the end. Bevel the screw's end on a belt sander. Run the nut off the end to clean up the end threads.

Ken


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## gi_984 (Feb 1, 2016)

I have drilled and tapped a few holes in a block of squared up aluminum in the mill.  Ran the screws up from the bottom then taken a few light passes with a endmill along the tops.  Fast and easy to do with smallish screws.  For bigger I've held them using the nut with the screw thru it and the nut in the lathe's 3 jaw.  You can also turn a piece of stock round, drill and tap, then hold in your 5C or 3 jaw.  All work well.  Just depends on size of the screw/bolts and how fast you want to do them. 



Fabrickator said:


> This is what I do. I made a 3/8" x 8" steel plate with multiple, common size, tapped holes and then heat treat. One side is SAE and the other is Metric. You need a pretty clean cut (deburred) so you don't screw up the jig[/QUOTE
> I've considered doing the same thing Fabrickator did.


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