Homemade Thumbscrew




Introduction: Homemade Thumbscrew

This instructable will show you how to make a custom thumbscrew with parts you probably having lying around. You can go to step one now or read the back story as to why I can up with this.

Back Story

I am in the process of buuilding a custom folding-hideway workbench. One of the things I want to do is have mounting points for my tabletop devices such as a Drill Press, Dremel shaping table, vise etc. But because the bench top folds away I need to be able to securely attach and remove the tools easily. So I will be putting threeded insert screws in the bench top in the appropriate places for my bench top tools.

I also wanted to be able to loosen and tighten the screws by hand so I didn't have to worry about having wrenches or sockets available.

My initial idea was to use 1" knobs that had the correct thread bolt in them. But they cost anywhere from $5 to $15 each and I need at least 12. So I set out to make something cheaper.

Step 1: Supplies Needed.

  1. A screw or bolt. ( I used a 1/4-20 screw, but any size to match your application will do)
  2. A nut (to match thread of bolt)
  3. A washer (to match diameter of bolt)
  4. Loctite Red (or any high strength thread locking glue.)

Step 2: Apply Loctite

Following the directions of the adhesive you are using, apply some to the tip of the threads.

Step 3: Thread on Your Wingnut\washer

Put the washer on first, then thread on the wing nut. I went one thread past the end to make sure it was secure. You will need to wait until the adhesive sets. In the case of Loctite Red, it's about 20 minutes.

Step 4: Cut Off Head of Screw

Now that the wingnut is secure, you can cut off the head of the screw or bolt.

Step 5: Clean Tip of Threads and Test

Depending on how you cut the head off, you may need to clean up the tip a little to allow a nut to be screwed on. Once cleaned, use a nut or, in my case a threaded insert that this will ultimately be used for, to test the threads on the cut off end.

Step 6: Test in Your Aplication.

This is one of the tools I will be scuring with these thumbscrews. The bench is not built yet, so this is a scrap piece of wood with the threaded insert installed.

As you can see in the second photo here, the screw is too long and will not tighten down. You have a choice here. You can either cut the screw a little shorter, or, as I did in the last photo, I just added a nut to it. Now it tightens down. I prefered this way because this now allows me to use the screw for other devices that may need the screw to be a bit longer

Step 7: Addendum: Alternate Means to Attach Wing Nut

Based on some users suggestions, I'm showing an alternate way to attach the wing nut to the bolt or screw. Thread the wing nut onto the screw so the "wings" are facing the head of the crew. Thread the wing nut up until tight

Based on the screws I was using, the head of the screw was too wide, so I marked off the excess part of the screw heard and grinded it down so it was as thing as the wing nut. If you use this method, be sure to wear gloves. The screw will get hot.

Once you have the head shaped the way you want it, secure the wing nut with Loctite, solder or weld.

I found this process a big cumbersome and for my liking, I will probably stick with my original process. However, I will put a nut on the screw so that once the head has been cut off I can remove the screw to repair any threads that may be damaged due to the cut.



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    23 Discussions

    Nice work! If you screw on the nut before cutting, clean out the end and then unscrew the nut, the threads come out perfectly as the nut acts as a die forming the threads while it unscrews.

    4 replies

    I thought about that, AFTER I had made this Instructable. I need to make a bunch more so I will try it.

    Why not cut of the screw head first and then screw on the wing nut the wrong way. Then apply the locktite to the cut end and thread the wing nut all the way up? This way the machined end of the thread will be unharmed.

    Maybe my previous post was a little unclear. What I ment was that you screw the wing nut on the normal end of the screw, but reversed with the wings towards the end where the screw head has been cut. English is not my native language...:)

    Just saw that you added my suggestion to de instructable. However, it was not really the way I was thinking of doing it. Do as your first image, but don't apply the loctite and turn the wing nut around with the wings towards the cut end. When the screw head is gone, apply the loctite on the cut end and screw the wing nut all the way up. This way it will actually be less cumbersome since you won't need to bother with getting the threads cleaned up. The messed up threads will even help the loctite ever so little when they are inside the wing nut.

    I have done this in the past without the loctite, I cut off the head screw the wingnut to the top, and apply so Silver Solder or Soft Solder. The upside is this way you have the original thread. The Down side is you need to clean off the Flux and polish the wingnut

    What I do instead of using Loctite is this: screw the nut so the thread extends just a bit (1/2 mm). Put that in a vise where it has a vertical spare in the center (only clamp loosely). Then give the thread a hard punch from the top (eventually you need to place the tip of a 2nd hammer). This will widen/deform the thread to it holds the nut almost like welded. Also, if you use the cut end for deforming you have the good side already where you need it.

    3 replies

    Or, if you have a welder, zap it and there's no way it will loosen up.

    I have a TIG welder, but it's such a pain to get out and use. So unless I have a major project requiring welding, it stays put away. But I did think of soldering it. The only reason I didn't solder it is I won't need to put a lot of torque on the thumb part. I have broken smaller bolts trying to remove them that were secured with Loctite Red. So in this aplicatin, I think that is good enough. :-)

    I have try that for our archery club bows and is working perfectly. But in case you do not have a welder this instruct able is very good idea.

    As long as the head of your bolt isn't too big and the wings on your wingnut are large enough, why not tread the wing nut UP the screw to the top of the nut. No cutting required then.

    2 replies

    Also this way you can lock the wing nut against the bolt head, which I would trust more than the Locktite alone. You can always file down the head a bit if it's too big.

    This might be possible if the screws were a small thread. Plus, I was using what I had laying around. But the heads are V shaped, so maybe this will work. I'll give it a try and post how it goes.

    One thing about Loctite and other threadlocker compounds - eventually they will fail. Sometimes it can take dozens of years, but it will happen. Making a small cut in the end of the screw after putting the wingnut on, then screwing the wingnut up to the end, and using a punch to spread the end of is another way to lock the wing nut permanently. Another good way is to use a propane torch to melt some solder into the threads - you don't have to braze it, just using some non-lead solder usually does the trick.

    Dammit, am i the only person who clicked on this in the email hoping to find instructions on building a torture device?

    3 replies

    Not hard to find one in a well stocked hardware store - look for those little external cut-off pinch-screws used on thin hose. First time I saw one, I wondered why we stocked torture devices in hardware stores(I was about 12 an taking a course on the Middle Ages, and had just finished a report on the Spanish Inquisition). I found out later they were used to reduce or cut-off the flow of liquids in thin flexible hoses. Made for a funny conversation with my father at the time, though.

    If you put a nut on before the washer and wing nut you can use it to clean the threads after you cut the bolt. Simply cut the bolt then unscrew the nut and it will clean off any burrs from the cutting.

    1 reply

    Aww .. ya beat me to it. I've been using this trick ever since I was around 8 years old, when I helped I dad make a stand for a little drill press he bought. He was working as a machinist at the time, and showed me the trick. It does help some to use a little sandpaper on the end threads after removing the nut though.