Make an Emery Cloth Bobbin

See warning and disclaimer at the bottom of the page!!

Overview

Wont FitWe have all been there at one point or another, we have 2 components that do not fit together, but only by a matter of hundredths of a millimetre or even worse a few microns. Enough to make assembly difficult or impossible, but not enough to remove using conventional cutting tools.

At times like this we need a solution that will get us out of trouble, something quick and dirty method that allows us to remove material in a semi controlled manner. This hint is both quick, and dirty, but it works, it may take a little bit of time (depending on the amount of material to remove) but if machining the components is not an option, this is certainly worth a try.

You do not need to have any fancy equipment to use this hint, only a means to drive a spindle, such as a hand drill or a pillar drill, however, the more stable the spindle, the more control you have over the final results.

Equipment

  • 75mm long Round Bar (approx. 6Ø – 10Ø, as long as it fits in the chuck of your chosen drive tool)
    • It is important to keep the bar as short as possible, as the stiffer the bar, the less effort you need to put in to remove material. Also, in my opinion, it is much safer with a shorter bar.
  • Emery Cloth, or Wet and Dry paper (grade is up to you)
    • Most cloth abrasives will work. I would suggest a maximum width of 25mm.
  • Engineer’s hacksaw
  • Selection of files to remove burrs
  • Bench Vice
  • Power tool (bench drill, hand drill etc.)

 Making The Bobbin

  1. First things first, cut a 75mm long billet off of you chosen diameter bar. (if you do not have any round stock, it is possible to make a shorter version of the bobbin using an available bolt or screw of a reasonable size).
  2. Remove any burrs or sharp edges from your billet with a file.
  3. Place your billet securely in a vice, standing vertically to allow you to cut a slot along the centreline of the billet.
  4. Use the hacksaw to cut a slot that is as long as your abrasive cloth is wide, tie or take a mm or so. The slot does not need to be particularly central or even straight, but of course the more central and straighter the slot, the more pride you will have in you home made tool once you have finished.

    Any round bar will do, even a spare bolt

    Any round bar will do, even a spare bolt

  5. Again use a file to reeve any burrs and sharp edges
  6. Remove a strip of cloth abrasive about 75mm long, place one end in the slot and wind it around the bar.

    This is the correct direction to wind in for a conventional drill

    This is the correct direction to wind for a conventional drill

We now have almost everything we need use the emery cloth bobbin for the first time, the only thing we are missing is a spindle to run it with and a little bit of on the fly assembly.

Warning – This tip should only be used with extreme caution, it is intended to be used a solution to get out of a tight spot, I do not recommend this for everyday use. Failure to heed this warning may lead to entanglement or other serious personal injury!

Disclaimer – All workshop tips and advice offered on this site is done so in good faith, I can take no responsibility for personal injury arising from anyone using the advice given.
PLEASE FOLLOW NORMAL HEALTH AND SAFETY PRACTICES AND USE PERSONAL PROTECTIVE EQUIPMENT AS REQUIRED, YOUR SAFETY IS YOUR RESPONSIBILITY!!