Thursday, January 10, 2019

Large Head Knurled Thumb Screws

I have discovered that turning thumb screws on my telescope is not so easy when wearing thick gloves in below freezing weather.  Larger knurled heads would help.  Ideally, these would be 1" diameter knurled heads for 6-32, 8-32, 10-24, and 10-32 threads 1/2" or longer.  (So many vendors of optical parts; so many choices of thread.)

I know there is a knurling attachment for my lathe, but it makes more sense to pay a few dollars each for these than to spend a hundred dollars (including the knurling tools) and likely several hours making these.  I tried MSC.   Any other likely sources?


  1. I collect brass stock from the scrapyard, some is hexagonal, most is round. It's easy and fun to make thumbscrews, but I have a bit (19") lathe and a CUT knurling tool. I've made some from hex stock, no knurling necessary. One method is to bore a hole that's an interference fit to the head of an Allen bolt of appropriate size, then press the head into the hole. Instant thumbscrew!

    Note that you'll want to use a "sleeve" type of tool to press the Allen bolt on the bottom of the head, not simply press on the end of the bolt. A decent vise will work to do the pressing if you don't have an actual press.

    An alternative is McMaster-Carr, they probably have a selection of thumbscrews.

  2. mcmaster-carr

    you could get some knurled solid metal metal/knob/thing and mill a larger plastic knob to press fit on top of it, relatively easily. might be necessary in order to get a 1" diameter knob for 6-32.

  3. IF you can't find 'em, you should be able to find wing headed bolts.

    Mcmaster has both:

    IF you need bigger things to grip, use these and make adapter studs to get to the thread size you need...You do have a lathe, right?

  4. There are plastic knobs designed to have socket head screws pressed into them. Available for various size screw heads. These work well enough to be used for OEM applications. Typically you use the standard mildly splined/knurled screw heads for this job. The smooth heads (typically stainless or plated) are not recommended.

  5. Amazon has a thousand of them; some with plastic knob heads.

  6.,43455,61994&ap=1 thuslike?

    Those are sold for use with 1/4-20 thread, but they just press-fit on the bolt head, so there's no particular reason they can't be adapted to metric threads.

    Grainger has a variety of such things, available in a multitude of threads.