Doggy DIY v2.0

The management was unhappy with one aspect of the new dogflap: the four fixing bolts protruded too far (about 2cm) and made sliding the locking hatch into place too fiddly. Now then. I have never successfully shortened bolts (where successfully = ‘and retained the thread’). So rather than try to find a set of four bolts that were precisely the correct length (like that would even be possible!), I decided to have a go at successfully shortening the bolts. A bit of Googling followed by some YouTubeing (I’m sure that’s a word) put me on the right path. I should have taken photographs, right? Well I didn’t. Anyway. Here’s how to shorten bolts without messing up the thread:

  1. Get on the Internet and spend £19.99 on a metalworkers bench vice
  2. Get your 1,000cc motorbike out of the garage
  3. Have a hot chocolate
  4. Get notification that the metalworkers bench vice is ready for collection
  5. Dress correctly
  6. Ride your 1,000cc motorbike to the store, 5 miles away, taking care to have a terrific time on the way
  7. Collect the metalworkers bench vice
  8. Return home, taking care to have a terrific time on the way
  9. Set up the metalworkers bench vice on your workbench
  10. Take the first bolt and wind two nuts all the way down to the head
  11. Measure the length you need to shorten the bolt to, and mark it on the bolt
  12. Wind down the other two nuts so that the top of the second nut (nut #4) is at the mark
  13. Tighten nut #3 so that it butts firmly against nut #4.
  14. Place the bolt in your new vice and tighten but not too tight, just enough to stop it moving
  15. Cut the bolt, with a fine hacksaw, using the top (outside) edge of nut #4 as your guide
  16. Rasp off the cut portion of the bolt to a flat, smooth finish
  17. Undo and remove nut #4. It might bind a little over the cut but don’t worry about that
  18. Undo and remove nut #3. It too might bind a little, but don’t worry about it
  19. Undo and remove nut #2. It should come off without any friction
  20. Undo and remove nut #1. It should come off without any friction
  21. Have a hot chocolate and a biscuit
  22. Rinse and repeat steps 10-20 for bolts #2, #3, and #4

There you go. Removing the nuts over the cut area redoes the thread and repairs any thread damage that cutting the bolt might have incurred. You’re welcome.

2 thoughts on “Doggy DIY v2.0

  1. I do something similar, but it doesn’t involve hot chocolate:
    1. Wind a single nut onto the thread.
    2. Shorten the bolt using the best hacksaw blade that you have… yes, that bent coarse one with lots of teeth missing.
    3. Then, using that very rough bastard file that you stole from the GPO many years ago, file off the sharp edges.
    4. Wind the nut back up the thread to the freshly sawn point, then back down again. File again.
    5. Wind nut up and down over the sawn point a couple of times and then take it off, crossing fingers that it will go back on again.
    6. It generally does.

    Yes, I am welcome… in most places.

    1. Ah, the ‘same but different’ school of application. I like it.

      (that’s not what I’ve heard – you being welcome in most places)

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