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I recently complete the restoration of an old 18 lapidary rock saw (slab saw - see photos). While showing some of the photos of the saw to some friends, they told me that another one of our mutual friends had a HUGH rock saw (24 diamond blade) in need of some work. Long story made short, I volunteered to put it in order.My only real challenge, and its a daunting one, is to finish the fabrication of the rock vice. In a rock saw, the vice is mounted on a carriage that sits on two parallel rails. The vice needs to not only be able to securely hold a large rock but allow for the positioning of the rock relative to the blade to regulate the thickness of the slabs to be cut from the rock.. Once the rock is secure in the vice, the rock is then positioned, via a screw mechanism, for the thickness of the cut. When the saw blade is turned on, the carriage, on which he vice is mounted, moves down the parallel rails towards the blade. As it moves the rock contacts the blade and as the carriage continues forward the diamond blade cuts the rock. In both the case of my rock saw and this one, the speed of the carriage is regulated by weights suspended on a cable via a pulley to the end of the carriage.The vice/carriage Im working on started out as a custom job. Unfortunately, the individual who was designing/fabricating the two was unable to complete the job.What I hope is that someone here will be able to provide some constructive suggestions/advice on the best way to complete the job. Ive attached some photos with descriptions. Let me say first off that the original build was atrocious when it comes to welding the parts together. Ive spent the better part of two days cleaning the vice/carriage and a lot of this time was spent removing the slag/flux from the prior poor stick welding job. That will be the easiest part of the job to fix!The requirement is to somehow attach a treaded rod that will push the free end of the vice against a rock and hole it securely against the fixed end of the vice. There are 3 pieces, which I assume were left over from previous attempts to solve this problem. My current thinking is to cut a 4 wide by 2 long slab of ½: thick sheet stock and weld two pins to the bottom to fit the guide holes in the base/floor of the vice. I believe that using two pins as opposed to just one will insure a more stable base for the vice screw. Next Ill weld a 2 x 2 x 1/2 piece of sheet stock perpendicular and centered on the base slab. Ill drill a ½ hole in the center of the perpendicular piece and weld a ½ nut on either side. By threading a ½ threaded rod through the two nuts/hole until it contacts the free end of the vice Ill create the vice screw. Tightening the treaded rod will move the free end of the vice toward the fixed end, clamping anything in between. Figuring out the best way to treat the end of the threaded rod where it contacts the free end of the vice is still an open issue. Ive been leaning towards using a ball and socket type joint like you see on a large C clamp. My rational is that this would allow the threaded rod to turn easily while maintaining solid contact with the free end.A couple of specific questions that I could use some help on:1. Coarse or fine thread (assuming ½ threaded rod). Which would provide firmer, more secure tension?2. Is there a better way for the threaded rod to contact the free end that a ball and socket joint?3. Is there a totally different way that accomplishes what I need to do more efficiently/effectively?Thanks in advance.The photos that do not appear here will appear on the next post!The 'before' photo of the rock saw I rebuilt:The 'after' photo: (note the vice/carriage with the attached cable/weights)The vice/carriage from my rebuilt saw:The one I'm now trying to complete. The 'free' end of the vice is on the right side and the base of the vice has evenly space, 1/2" holes in the baseThe 'spare' parts. The 'L' shaped piece with the pin was probably intended to act as the base for the vice screw (threaded rod). The threaded rod with the round disk was probably intended to push against the 'free; end of the vice.The 'L' shaped piece with the 1/2" pin positioned on the base. This is my best 'guess' of the intent - which was to weld a couple of 1/2" nuts to this 'L' to hold the threaded rod. Moving the 'L' by repositioning the pin reduces the lenght of the threaded rod required.The reverse side - this shows the lateral adjusting screw, moves the vice lateraly on the carriage to regulate the thickness of the slab to be cut.
Reply:The 'easy' part of the project wil be to fix the existing welding job. Just a lot of grinding and re-welding. Here are a few photos. Unfortunately my photography skills sometimes are as bad as these welds - the photos of the worst weld dodn't come out well enough to post. But you'll get the idea.
Reply:Very nice work on the vice you built.You've definitely got some work ahead of you grinding and re-welding. Might find that cutting the parts off and starting from scratch will be the best way to go.As for the vice screw, I think an acme thread would be the best way to go. Much stronger and more tolerant of a dusty environment. Unified national threads are less tolerant of constant tightening/loosening and have tighter fit tolerance. Looks like the vice you built has a nice screw arrangement though. If you use unified threads I think coarse thread would be better suited Rather than using nuts, might want to weld in a piece of stock thick enough for good thread support then drill and tap after welding. 1/2" seems a little undersize for the vice screw. Can't tell what size is on the vice you built.Hope it helps some. AlA man is judged by what's between his legs...always ride a good horseMiller DialArc HFLincoln Classic 300DThermal Arc 181iPowermax 45Scotchman Ironworker(2) BridgeportsOkomota Surface GrinderAutoCAD 2010
Reply:Wow, somebody used a 110v to get those things to stick together.... Taking them right off as the PP said, is the way to go I would think.Cheers,Miller Diversion 165120 amp Buzz BoxVictor Oxy/Ace Oxy/LPGSmith "Little" Oxy/LPGHypertherm Powermax 30Lot's of Misc. tools n' crap....
Reply:You might find the screw from a heavy steel clamp may take care of what you are looking for. Get a steel one not one of the cheap cast imports so you can cut off the C and just use the screw and threaded part.You also might find a cheap wood workers bench vise and be able to adapt that as well. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:After a lot of though and consternation I decided on an approach to the carriage/vice. I was limited in what I could do by cost and materials so I basically used whatever I had available - no parts or material was purchased to compete the carriage/vice.Since I reorganized the photobucket photos I'll repost them. Here are the results of my effort:The seven photos photos are the Before photos before any re-design or fabrication but after I spent several hours cleaning and sandblasting (I didnt think of before/after photos until Id already cleaned most of it ).The bottom of the device is the carriage that rolls along two square rails set on edge (the wheel on the bottom left is one of four at each corner that rides on the rails. Above the carriage is the vice component - with one fixed side (jaw) and one moveable (free) side (jaw). There is a threaded rod, actually the screw rod from an old, large C clamp that provides the lateral movement of the vice and determines the thickness of the slab. The vice also rides of two round steel rods running through brass bushings on the bottom of the vice for lateral stability. The holes in the floor of the vice were intended to be used to limit the length of the screw needed to move the free jaw. Below are two photos of the vice with the originators attempt at a designing/fabricating a base on which to attach the screw that moves the free jaw (the L shaped piece with round stud). The threaded rod with the round plate and nuts was probably welded to the L base and pushed against the free jaw (just my assumption). (also note the cracked weld on the floor of the vice). Another photo of the vice from the side that operates the C clamp screw which traverses the vice on the carriage. The end of the screw had the threads remove so a hand wheel, attached with set screws, could turn the traverse screw. I spent several hours grinding away and re-welding most of the really bad welds. I admit that some I did for cosmetic reasons they were just so bad. Heres what I came up with. For a fixed base from which to move the free jaw I designed and fabricated a mobile-fixed base. Mobile in the sense that it uses the holes in the floor of the vice and a removable pin to initially position it and fixed in the sense that once the pin is installed through the base and into one of the holes in the vice floor it becomes fixed in place. I used ½ steel flat stock for the base and drill and tapped the vertical part to receive a 5/8 threaded rod. One the vice end of the threaded rod I machined the end to ½ diameter and the cut a ¼ groove in that end, ½ from the end. This end fits into a ½ sleeve into which I drilled and tapped ¼ threads. Two ¼ set screws (Allen screws) hold the threaded rod to the vices free jaw allowing it to be retracted. On the opposite end I welded a ½ ring (cut from the same sleeve material) and used a bolt as a handle. By initially positioning the moveable vice jaw against or near the rock to be held and inserting the pin into the mobile base, the maximum length you have to turn the screw is about ¾ as the holes are roughly spaced ¾ on center. This has the advantage on requiring a relatively short vice screw which, along with the whole carriage/vice, fits entirely under the saw cover. Had I welded the mobile base to the vice floor the screw would have had to be at least 12 long in order to accommodate a 12 wide rock (slightly less as the 24 blade wont cut all 12). The mobile/fixed base also has wrap-around sides (Basically the side of the base form a channel that fits the sides of the floor). I found that tightening the screw against the vice caused the base to tip and bind so I added the wrap- around portion to prevent the tipping. I would have used two pins but the holes were not precise enough to accommodate two pins. I also made a smaller, simpler mobile base that nests between the diagonal sides of the free vice jaw. Its faster to install and adjust that the larger one and, when used on small rocks requiring less tension, adequate enough to hold small rocks securely. Here is another photo of the mobile base (the support braces just look canted in the photo due to the weld shadow they are perfectly perpendicular and square to the face). You can just see the ring that is used to pull the pin on the large mobile base. Also pictured is the small base and extra pin. The pins are just ½ sections of a steel bolt drilled to receive a split ring, (my bad weld , embarrasing but by this time I was beat ) This photo show the traverse screw which moves the vice towards the saw blade and regulates the thickness of the slab. I discovered two major problems with the initial design. First, the threaded C clamp rod had, due to its coarse threads, way too much play in it. A threaded sleeve, probably cut from the original C clamp was welded to the underside of the vice. Because a C clamp depends on tension, the threads do not have to be tight. On a rock vice any lateral play will cause the saw blade to bind and possibly irreparably damage the blade. Second, there was a 6 diameter wheel handle attached to the end of the screw to turn it. This 6 wheel protruded almost 5 above the floor of the vice greatly limiting the width of any rock to be held by the vice. I solved both problems by using a 1 ½ diameter steel disk made from 1/8 thick flat stock. First, I threaded the end of the screw to receive ½ nuts which securely holds the disk to the screw. Then I drilled a ½ hole in the center of the disc. I drilled four ¼ holes around the outside of the disk. I fabricated a handle (sorry, no photo - visualize a screw jack handle) with two ¼ prongs welded to one end. The prongs fit into the ¼ holes on the low profile disk and allow the operator to traverse the vice while holding a rock at least 24 long (actually longer that the saw tub is wide). The disk is below the floor of the vice so as not to block the rock. To eliminate the play in the C clamp screw mechanism, I drilled a corresponding hole in the side brace of the carriage. I can slide a ball-lock pin through the disk and into the side brace hole effectively locking the screw in place. Turning the screw from one hole to the next causes the vice to move about 1/8 laterally. By adding four more holes you could refine the lateral movement to 1/16. Essentially you can cut slabs in 1/8 increments as it now sits. My friend also wanted a way to attach a safety strap (ratcheting tie-down strap) to help secure any rock in the vice. I welded on a strap ring to the fixed jaw. The other end of the strap can use the sleeve on the back of the free jaw to attach it.Finally I polished all the bushing and bearings and bearing surfaces. The carriage slides on the rails smooth as silk. Initial testing of the carriage/vice proved both the design modification and fabrication. I even replace the plywood pads on the vice jaws with ½ thick conveyor belt material which will provide a much better grip on the rock. A little Hammered Look paint and voila a working rock vice! This final photo is of the carriage/vice from my rock saw. Note the fixed base and long screw. Had I welded the mobile base I would have had to use a much longer screw to operate the vice and would have had to cut the tub cover to accommodate it. Still, had I the machining tools I probably would have adapted more of its design.(due to the limitation of number of photos this will be on the continuation thread)Last edited by reefera4m; 08-05-2010 at 08:41 PM.
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Reply:i hope your work is better than the post it may be just me but the ends are cut off
Reply:Your right - I tried to format it but could get the 'Remove Formating' option to work and when I tried to edit it I went over the 30 minute limit. Got a 'Contact the Administrator' message, sent the Admin a message and got no help. I'll try to format it later.Too late - now I can't edit the original thread at all - Sorry
Reply:Unfortunately I can't edit/format the thread at all now. Sorry |
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发表于 2021-8-31 23:50:22