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Inexpensive bolt extractor
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Kevin Ho at RDB Bearing and Mechanical Parts says they can do it. $6.00 USD upcharge on $19.49 w/free shipping = $25.49 They also sell the ball screw bracket/housing. Theirs cost $5.95 w/free shipping if you just order one ($4.39 if you order 3). All the tapped holes are M5. I will order one and figure out the length of counter-sunk screws required along with a handle design. Since you have a flat block with screw holes, you could essentially bolt any tab of metal strong enough to use a crescent wrench against and it will work. A tab instead of a fixed handle would allow for using it in tight spaces since you could get at the tab from the left or right. The additional parts on the shopping list would be the 1" square tubing, bronze thrust bearing, big flat washers. On the tail end of the tool it is machined for a circlip at the bearing side. My idea is to use another big flat washer as the backstop for the ball nut, then a nylon spacer, then a circlip. If you drill a 1/4" hole in the washer you can run some 6 mm cord through it and have a tether that swivels as you screw the tool onto the bolt. Total cost for the parts is still less than $40 and a hacksaw and drill are the only tools needed. Making a spinner tool without buying the parts in bulk might cost another ~$16  |
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1\2_20 UNF 2A Major diameter: 0.4987 / 0.4906 Pitch diameter: 0.4662 / 0.4620 Minor diameter :0.4392 / 0.4256 Pitch: 0.05 Convert these values to metric and the machinist will have everything they need to machine a proper thread. They are using a CNC machine, there's no reason why they can't produce any thread you want. Hopefully they will have a thread mic to measure the pitch diameter. |
Gregger Man wrote: I would definitely buy one. I've been following the thread in hopes of trying to build one of these tools this summer. |
Gregger Man wrote: Yes, I would definitely be interested in buying one. Keep us posted! |
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I would also like one. |
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I'd buy at least one and probably a couple more to donate to the surrounding area's good samaritans. |
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Update: order placed.$31.44 total for the ball screw and block to make a handle. I will give another update after I get the parts and provide a full shopping list for the complete tool. The square nut in 1/2-20 is available from McMaster-Carr, but you have to buy a pack of 25 for $9.49. The 1/2-13 version is available at most any hardware store cheap, but you need to run a 1/2-20 tap through it to cut fine threads. If you want to go ahead and order right now, use the diagram I posted earlier and talk to Kevin Ho at RDB Bearing.
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I'll buy several. Our local climbing org would put them to good use. |
Gregger Man wrote: Of course it is co$t dependent, but i know of at least 3 people in my crew who would pony up for something like this. PLEASE! |
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Well if you're looking to crowdsource buyers for this specific part, I'll put it out this offer: I don't have the tools, knowledge, skills, or craftsmanship to do a good job making a version of the doodad. But, a friend and I have a rebolting project for this spring after the snow melts out. If somebody out there is willing to make me a doodad and ship it (unless you're in the Durango area or alternatively the Chattanooga area before I fly back on Jan 3rd) I would pay for parts and pay generously for labor and love in your choice of cash, brews or herbs. I'm also looking for a spinner tool and hook tool for 5-piece bolts, although I may not have the cash for it right this second. |
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Update: Parts arrived yesterday. Free shipping, so no complaints from me on the three week delivery time. I'm editing a video to show what I got, the additional screws and such from the hardware store, and how it is all assembled. I'll post that to its own thread when I'm done. If you plan on ordering one, I think this is the final/best iteration of the Doodad. Aliexpress.com -> create an account -> go to RDB Bearing and Mechanical Parts -> search for "SFU1605 300mm Ball Screw Rolled C7 ballscrew SFU1605 L 300mm with one 1605 flange single ball nut BK/BF12 machined for CNC parts" Send a message to Kevin Ho with the diagram from the previous page and he can take care of the rest. The bracket can be found from several different sellers on Aliexpress, but I bought this one from the same seller for $5.95. It weighed 5 oz which is fine, but I chose to cut it in half to lose excess weight. Took 20 minutes with a hacksaw, so you need some patience. Finished tool weighs 2 lb 5 oz. If you knew you wouldn't need ~7" of throw you could dramatically shorten the length and possibly cut the weight in half. You probably won't need more than 3" of throw if you are only pulling 3/8" wedges. The draw studs for Rawls need to be as long as the longest potential bolt, and the spacer must be that long plus the length of a sleeve. Edit to add: I also ordered ball bearing thrust bearings from Aliexpress from a different store. Search for "5Pcs 51103 Axial Ball Thrust Bearing 3-Parts 17mm x 30mm x 9mm Free shipping High Quality" I got 6 of them for ~$7.00. All of the stuff arrived on the same day. Alternately you could buy a one-piece bronze thrust bearing and a big flat washer at the local hardware store for ~$4.00 or so. 
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I would also put down some money for one, or a few to donate to various rebolting efforts. Im in El Potrero Chico now and trying to get a few locals trained and tooled to do clean rebolting. I also plan to do this at a few other crags as i travel (and do a fair bit of rebolting as well). Would also want spinners to provide to them. |
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I'm here in Potrero Chico (one of the locals Jeremy is "training") and would definitely buy one as well. |
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Moved this post on the issues with bolt removal in limestone found by the sustainable rebolting crew in Mallorca to the Bolt removal tools - resources, tips, how-to videos thread. |
Rudy Peckham wrote: To be very clear - my whole purpose here is to make an open source bolt extractor that anyone can easily make for themselves with minimal tools, effort, money, expertise, etc. I will not be making and selling these. Simply follow the instructions in this thread and you will spend about as much time making the Doodad as it takes to remove your first 3/8" 5-piece bolt: |
 Not sure if this has been mentioned in this forum yet, but you can buy a 3/8" 24 to 16 tpi coupling nut from McMaster-Carr (Part Number-98434A113). Pair this with a 3/8" 24 tpi SDS Chuck bit adaptor and you have a spinner tool with three parts including the set screw. I've used it a few times now and it works great! I find the one I have with thread inserts tends to always come apart after spinning a few bolts. |
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Yup, that can work. The only drawback to having a spinner tool coupling that ends in 3/8-24 is that if it doesn't match the threads on your pulling tool, you have to remove the coupling nut from the wedge bolt after spinning it in order to start pulling. It isn't always easy to get needle-nosed pliers to hold the wedge bolt in place while you attempt to un-screw the coupling nut. Having a streamlined process where the spinning and pulling are easy to alternate is really helpful for efficiency's sake. |
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My current version of the Doodad. With the end caps, the threaded rod can't fall out.     |
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That's pretty cool, Dan. Thanks, again, for suggesting the ball screw over other thread types. That was a game-changer improvement. |
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I've ordered a bicycle headset wrench that works for the 40mm ball-nut I am using. $7 to $11 on Ebay or Amazon. It may not be sturdy enough. One end is a 40/36 mm wrench and I will probably mill out the 36mm part. I'll cut the other end off. It should be here in a day or so.  |
