Tips for gaff sharpening and maintenance

Have you looked at your gaffs lately, have you used them for bush bashing or rock climbing or have you just attacked them with the bench grinder. Gaffs are one of the most neglected items of the climber’s equipment yet they are one of the most important. Most people rarely even read the instructions when they purchase a set of tree climbers.
How important can a piece of equipment be that provides a foot hold were there is no foot holds, a piece of equipment that allows you to climb a smooth trunk to any height or walk a limb to its very tips. I would say very important wouldn’t you?
Yes gaffs, that little piece of possibly sharp metal at the bottom of your tree climbers that overlooked item that only gets attention when things get desperate or life threatening. Gaffs are one of the least understood items of the tree climber’s equipment, they are a precision designed and machined tradesman tool that needs care and respect .Yet we treat them like shit. We walk through bush and over hard surfaces and we rarely sharpen them or we sharpen them incorrectly but still we rely on them life support while climbing.

I have had the pleasure of seeing some amazing things in my time and one of them springs to mind as I write about this topic. Picture a concrete nail welded to a piece of bent flat bar with some dog collars attached to form a set of primitive tree climbers. A homeowner so proudly showed me these as I prepared to dismantle a nasty tree on his property. He said they were made and used by his late father for pruning trees on his property. I am certain you have some good stories to tell about tree climbers as well.

The most important thing about caring for your climbers is sharpening, the gaffs need to be correctly sharpened and have an edge as sharp as a wood chisel. When sharpened correctly they will dig deeper into the wood when loaded with your body weight but when poorly sharpened will peel out on every step. You should only need to stand on the gaffs to seat them in the wood. If you need to drive them in then this means blunt gaffs and that means excessive stain to the legs and joints.
Never file the side slopes or the top ridge of your gaffs (see fig one).Gaffs that have been filed on the top ridge or the side slopes are hard to correct, the top ridge tends to be rounded towards the point and this can not be corrected without filing a large amount of material off the under side of the gaffs to create a perfectly straight top ridge. Lots of tree climbers I have seen around have this problem of incorrectly sharpened gaffs. This causes the gaffs to roll out of the wood when loaded and especially when the body is pulled into the tree when stepping up.

The gaff is like a chainsaw chain cutting tooth in the sense that you only sharpen the under side of the tooth not the top side. Try placing a straight edge on the top ridge of the gaff and see if it touches all the way to the very tip of the gaff. I use the edge of a flat file to see if the tip rolls away from the file. For the gaff to work as it was designed, it must be flat on one side and bevelled on the other, very much like a wood chisel.

Good gaff care certainly means a safer climb but it also means an easier climb with less effort and more security and confidence for the user. Take a moment to read the check list below and then carry out some maintenance on those sad and sorry old gaffs. I promise you the rewards are worth it.

Please note: Tree climbers should be treated with respect, they are a lethal weapon in the hands (or on the feet) of the inexperienced and can be threatening even for the experienced Arborist. This is why some people call them calf cutters and why some climbers bare the scars of a poorly placed gaff.

The importance of sharp gaffs:

1. Worn gaffs can be more dangerous then razor sharp gaffs.
2. Worn gaffs tend to tear down and slide out of the wood.
3. Worn gaffs require more effect to drive them into the wood.
4. Worn gaffs place excessive strain on the leg joints and muscles.
5. Worn gaffs cause associated accidents when they slip out.
6. Worn gaffs make climbing more strenuous and difficult.

Key points to remember about sharpening gaffs:

1. Use a fine tooth 150mm long flat file when sharpening gaffs.
2. Only file the under side of the gaffs never the tops.
3. Sharpen gaffs little and often to maintain a good edge.
4. Never use a grinder to sharpen gaffs as you are likely change the temper.
5. Secure tree climbers in a vice with the under side of the gaffs facing up.(See Fig 3)
6. File towards the point of the gaff, from heel to point for safety.
7. Remove only sufficient material to make the edges sharp and the profile correct.
8. Always remove cross filing marks as they weaken the gaff.
9. Improve the edge and remove file marks with a small oilstone.(See Fig 3)
10. The full under side surface should be filed equally to maintain the profile.
11. A uniform amount of metal should be removed from the under side surface.
12. Uniform removal will maintain the proportions of the length, wide and thickness.
13. Maintain a flat surface from side to side when filing the under side of the gaffs.
14. Avoid a very fine point as it may snap off when driven into hard deadwood.
15. A short thick point is always stronger when working on dead hardwood.
16. Use a gaff gauge to check the proper width, thickness and point profile.(see Fig 2)
17. The underside of the point should have a radius to the tip, not an angled flat.
18. Never file the side slopes or the top ridge, as this will create a roll out effect.
19. The top ridge must be kept perfectly straight all the way to the very point.
20. Use an oilstone to remove burrs on the side slopes and top ridge.
21. Correctly sharpened gaffs will keep digging in deeper when weighed.
22. Wear gloved hands when sharpening gaffs to avoid nasty cuts (unlike in Fig 3)

Next: Expect the Unexpected