Yet Another Bolt Remover

Hi Folks,

I've been playing around with a few of the bolt extractor tool designs post here over the last couple of years.  I've been really impressed with the ease of use, power, and smoothness of Greg German/Dan Merrick's ball screw design.  Since I have access to a machine shop and good machinist and do a bit of CAD for my day job, I decided to add a bit of convenience functionality to the designs as well as try to make a design that could be built by people without metal working skills or access to tools/shops.  

The result is the Yet Another Bolt Remover (YABR, pronounced YABR).  Its really the Doodad 4, but I don't want to co-opt Greg's name without permission!  It features a removable handle (if working in a corner or around a rock feature that prevents the convenience of a fixed handle, the handle can be removed via a thumb screw and a crescent wrench used instead). The square tube is 'captured' to the rest of the tool so that it can not slide up/down the ball screw to prevent marring the threads.  The front piece is intended to spread the load over a larger area of the rock face to prevent chipping, and could be modified for software rock if necessary.

If enough people are interested (10?), I can get my machinist to make a run.  Total parts cost (ball screw, lots of McMaster parts, plus machined parts) is about 250$.  

Also, if any wants to machine these themselves or improve upon the design, I will happily share my CAD models as well.
 

Cheers to all of the tool creators and bolt replacers out there!

Love it!
You can call it whatever you like - YABR, Doodad 4.0. Regardless, it looks skookum.
$250 will get most folks to balk, but I get why the cost adds up when you start machining things professionally (as opposed to the caveman approach I typically take).
Do you have a backstop to keep the ball screw from going off the deep end?

Thanks Greg.  Yeah, I know the price will scare some, but I think if you were using it often it would be worth it.  Or didn't have the tools or skills to build one 'caveman' style!

Yes, I added a spacer and a retaining clip to prevent the ball nut from exiting the back.  These are the parts:

https://www.mcmaster.com/97414a645
https://www.mcmaster.com/93320a305

However, at the Access Fund's Vertical Stewardship conference someone backed the ball nut into the spacer/clip and popped the clip off.  Adding a set screw to the spacer would probably be more robust.  In a previous prototype I used one of these bad boys:

https://www.mcmaster.com/61135k58

but I couldn't justify the cost nor weight.  Any ideas would be great!

cs

What sort of force can it pull?

Hey Jim,

That's a good (and fair) question, but I have no idea.  Certainly nowhere near the 'glue in' puller that was demonstrated at the Stewardship event!  It would be no different that the ball screw Doodad, if Greg has any input there. I have broken brand new 3/8" wedge bolts in test rock, but almost any of the designs are capable of that.  

cs

$250 each(!) or for the batch of 10 ($25ea)? How are the ball-screw pullers much better than a Hurley Jr? In my limited experience, it doesn’t take so much force to pull bolts that a HJr isn’t sufficient. Sorry if the second question is answered elsewhere

Drew, 250$ each. All the variations have sufficient force, the question is ease of use and durability.  My experience with designs that use traditional v-thread screws is that they have a lot more friction, like to bind, and are susceptible to dings in the threads with use (I've had to replace the screw on my v-thread tool a few times due to dings).  The ball screws take less effort, give you better feel (which gives you better warning when the cone has re-engaged and you need to spin some more), and are much harder to ding.  

I don't expect most people are interested in paying for the difference, but like I said, if you are replacing a lot of bolts I think it is worth the extra money.

cs

cleatis wrote: Hey Jim,

That's a good (and fair) question, but I have no idea.  Certainly nowhere near the 'glue in' puller that was demonstrated at the Stewardship event!  It would be no different that the ball screw Doodad, if Greg has any input there. I have broken brand new 3/8" wedge bolts in test rock, but almost any of the designs are capable of that.  

cs

Most of the pullers I make are for testing bolts to destruction so have to run around the 60-80kN level (my bigger "portable" one will pull 100kN easily) but weight becomes an issue with hydraulic systems. I´ve also made a few mechanical ones just for low-load testing (8kN) using Belleville washers to show the force applied but when I look at the tools you guys make I´m kinda in the dark, I´ve no idea what it takes to pull out a 1/4" buttonhead or whatever! I was interested in how much force you get with a ball-screw system compared with the fine-thread ones I´ve made.

Dan Merrik demonstrates a 25kN axial pull in this video using a ball screw puller:
https://youtu.be/vpxKZrKNnV0
He breaks a perfectly healthy 3/8" bolt held in a vise. We typically are removing 1/4" or 3/8" bolts that are far from healthy. Once they are either rusty enough to have no moving parts or have been hobbled by a spinner tool, they can slide at ~1 or 2kN. If the bolt re-engages and fights back, I'm guessing that I get up to ~8kN before I back down and try something else to undercut the holding power of the wedge like more water or more spinning.

Thanks, that the sort of info I wanted. The few simpler ones I´ve made pull around 20kN which does the job but I was wondering if the extra weight/cost/complication was worth changing to ball-screw. Whether it´s easier isn´t really a consideration, I give them to strong young guys!

I want one! Id pay the $250 easy.. 

Jim Titt wrote: Thanks, that the sort of info I wanted. The few simpler ones I´ve made pull around 20kN which does the job but I was wondering if the extra weight/cost/complication was worth changing to ball-screw. Whether it´s easier isn´t really a consideration, I give them to strong young guys!

The main benefit of the ball screw over fine thread is ergonomic - fine thread gives you leverage in exchange for such tedium. When you are hanging in an awkward position you often don't want to spin a wrench for 60 revolutions. The ball screw has such little friction that you can thwack it and it keeps turning. 8 revolutions per inch is much more convenient in practice. 

Anonymous wrote: So shinny! Nice job.

How finalized is the design now? Are those 3 different versions or are they all the same at this point?

Thanks Nate- they are all the same.  The design is finalized until I get more feedback!

I run the RRG FGI.  This is interesting, but a bit cost prohibitive.  If you don't mind me asking... what is the cost of materials?  Are you making these with an intent to make profit or to contribute to the community?  (not that they have to be mutually exclusive)

Thanks,

Ian

Cost of materials is 237$, which includes my machinist's labor but not mine.  I rounded up to $250 to cover shipping costs.  I am not trying to make a profit, just offering these to the community since I enjoy good bolts more than bad ones.

Perhaps we could finder a climber machinist to donate their time to get the price down to just cost of materials?

climb2core wrote: Perhaps we could finder a climber machinist to donate their time to get the price down to just cost of materials?

The machinist is a climber, but he still has to make a living! The machine labor is ~115$, so it would save a good chunk.  Even better would be to get a company or non-profit to take this project over!  

cleatis wrote:

The machinist is a climber, but he still has to make a living! The machine labor is ~115$, so it would save a good chunk.  Even better would be to get a company or non-profit to take this project over!  

Perhaps we can find a machinist that would do it as volunteer work.  I have one I can ask.   Thx!

cleatis wrote:

The machinist is a climber, but he still has to make a living! The machine labor is ~115$, so it would save a good chunk.  Even better would be to get a company or non-profit to take this project over!  

I wonder if the ASCA would be interested in helping out with this project. The access fund provides a hurley jr but as far as I'm aware, the ASCA only provides spinner tools to people looking to rebolt. 

climb2core wrote:

Perhaps we can find a machinist that would do it as volunteer work.  I have one I can ask.   Thx!

Let me know and I can provide the models and BOM.  

An anonymous donor has offered to chip in for the purchase of one of these tools for the RRG FGI, which is pretty cool. There are 3 other people potentially interested in one so far, if a few more come onboard I can justify a run. Let me know if you want the anonymous donor up on the offer and I can add you to the list of maybes.

That puller is damn sexy! I'd shell out the 250 bones to upgrade from my ghetto-rigged pulling methods.