Drill Holders

[mungeclimber]

Saw one of your drills in action last weekend Dan. The leash was a swage, that frayed immediately. I like how it is shorter.

my rocpec is on its last legs. Got any left?

[daniel banquo merrick]

Sure Munge, I have some holders. Who did you see using one?

Besides the ones I been using I have:
4 medium bayonet type
4 short bayonet type
2 A-Taper type
2 A325 bolt type

I still have trouble with leashes. It seems like if I get them sturdy enough, they won't rotate. I have replaced all the crappy swages that John commented on with copper Nicopress ones. They seem to work pretty well but I don't know for sure since I never use a leash when drilling. I only use them to hang on a carabiner.

The 2 A325 holders are turned from 7/8" A325 bolts. A325 bolts are what they use to bolt steel buildings together. The steel is tough, fairly ductile and high strength. They have a deep socket shown in the photo below with the usual 6-1/4" x 3/8" SDS drills. The drill is held in place with two set screws similar to the old Pika drill. The set screws are set with thread lock which I have found keeps them from working loose while still allowing them to be removed. The larger head makes a good leash easier to do and the cord leash works very well. Pretty bomb proof but heavier. 14.4 ounces with the bit installed.

People are giving me $80 for the bayonet type, $50 for the A-Taper and I'd take $40 for the A325 with leash. Send me a message if you want one.

[John]

Those bolt-type drills look badass. Nice work.

[YETI]

Man those are sweet!

I may however hang up my hand drilling days, as i destroyed my wrist using a Mcdevitt hammer and a hurricane drill combo.

I will proudly serve as sub-man on any further forays into pro-less leads.

FML

[mungeclimber]

Man those are sweet!

I may however hang up my hand drilling days, as i destroyed my wrist using a Mcdevitt hammer and a hurricane drill combo.

I will proudly serve as sub-man on any further forays into pro-less leads.

FML

That's not exactly an admission that you will start using a bosch, now is it?

[daniel banquo merrick]

I've searched the academic journals and there is surprisingly little about hammer ergonomics. There are few few papers about handle shape and these found a curved handle very helpful. This is what you see on most framing hammers these days and what we used to call a hatchet handle. Basically they say you can swing the hammer with your wrist in a more natural position. I've read the paper and the main problem i have with the study is that they used some students and faculty to evaluate the hammers. I guess they couldn't find any carpenters or blacksmiths on campus that day.

From Human Factors: The Journal of the Human Factors and Ergonomics Society:

The theoretical justification for putting a bend in a tool handle is reduction of stress on the flexor tendons and median nerve as they pass through the wrist. Our three experiments used brief «5 min) trials of people without wrist problems. The overall conclusion is that people like a bend in the hammer handle (although not as much as 19 deg) and that there are no performance differences. Note that driving a nail straight with a bent handled hammer is not a problem

Applying the established ergonomic principle of bending the tool and not the wrist to the hammer could produce less biomechanical stress on the wrist while maintaining the performance of a straight hammer. For novices, bending the hammer handle to 20 or 40 degrees significantly reduces ulnar deviation and might decrease the incidence of CTDs caused by the hammer.

cumulative trauma disorders (CTDs).

[YETI]

Bingo Dan.

Sloppy technique caused this from a bad drilling stance.

Lotta holes on my wrists, bound to happen sooner or later.,

[John]

Are you getting Bosch-Curious YETI?

[YETI]

May have to start free climbing now.

I tried the machine once, maybe again the next morning? On some anchor bolts.  I had been drinking and was peer pressured into it by my closest friends.

It was low moment, and I had to find a local group to meet with, eat doughnuts, and talk about my problem for months afterward.

I may slip again, and need everybody to keep an eye on me, don't want any little boschlets on the rack just yet.

[daniel banquo merrick]

I pulled out the drill holder that we have been using this past year to see how it is holding up. Bob is a pretty good tester since he likes to hit (too) hard. I let him use my holder and some stubby bits both of which are more efficient at transferring the impact to the bit. He hits just as hard so all he does is blow out carbide tips every bolt or two. I may have to buy him a girlie hammer.

The swaged leash is holding up well although I think it has only been used to hang the holder on a carabiner. The striking surface looks as good as new. The set screws that keep the bit from rotating are in good shape still. The four screws holding the springs are still good. The thread lock that holds the springs and spring screws in place is working well.

The end of one spring has broken off and the spring on the other side has a crack. Where the spring is broken off I can see a slight bulge where the ball bearing has been pounding against the steel. The broken spring doesn't seem to affect function at all.

If any of you have a holder with broken parts,  I'd be happy to fix it for you if you can get it to me.

[John]

That sure doesn't look like a drill with a year of use.

[daniel banquo merrick]

When I first started making drill holder I considered putting the leash loop at the bit end of the holder where it wouldn't get hit by the hammer. Bob convinced me not to saying it would be in the way there. It still seems like it might be a reasonable place to put it. Even if the holder is short and your hand wraps the leash it would work because your hand would simply turn the leash as you turn the bit. This would require making the holder a bit longer.

Another idea would be to make the groove wider and use a piece of tied cord rather than cable. This might require making the holder a little bit longer because I don't like removing too much of the material wrapping the striker insert. Although this has never happened, I have always been concerned that the dowel pin insert would become loose and the pin fall out.

I have bought some slippery plastic coated cable that is more flexible and slides in the groove better but I still think that if you hit the swage with the hammer, the loop is a goner.

Any thoughts?

[John]

You have to strip the coating of that type of cable or the swages are really weak.

I was considering a similar design placing the loop lower down to be clipped as backup for if you slipped. Less leverage down lower. It would work like how many hand drillers clip the bit with a daisy while drilling so the bit may catch a fall. If the hole is deep enough, they can and do hold you and have saved quite a few folks from the big ride.

[daniel banquo merrick]

The leashes I've made in the past have not been very good so I decided to come up with something better. I made the holder a little longer which gave me space for a cord leash. I was concerned about not leaving enough material to hold the dowel pin (striking surface) securely so I used a longer pin and drilled a deeper hole for it. I was supposed to end up with 1/8" of the 1" pin exposed but when I hammered the pins in, they wouldn't go in all the way. I know hammer blows can generate about 10,000 pounds on a solid surface. I decided to try and press the pin in and put it in my test frame with a 20 ton cylinder. I got to almost 30,000 pounds when the holder crumpled. Darn pin didn't go anywhere. Either the fit is way too tight or I didn't drill the hole deep enough.

I made two of the new design and the leashes seem to work really well. They rotate easily and don't bind up. I still have one left and was wondering if anybody wanted it. Since the pin didn't seat right and I tapped one of the screw holes a bit crooked, anybody who wants it can have it for $40. Maybe Munge will want it.

Test frame:


Crushed holder:


Remaining holder:

[mungeclimber]

must... not... reply...

save... elbows... save... wrist...

cool... design...




CRUXING!!! 



ok.


I'm such a push over.