portuncia Posted June 15, 2006 Posted June 15, 2006 When you cut your new keyway for your bevel shaft I can see using a die grinder or cutting disk to cut the channel/perimeter lines but what did you use to remove the 3/16" of metal to make the groove.
jlasater Posted June 15, 2006 Posted June 15, 2006 As it needs to be fairly accurate, I'd have a machine shop do it with an end mill. Should be a 5 minute job for a shop with the right equipment.
HubbardRA Posted June 15, 2006 Posted June 15, 2006 Jeff, I stacked three of the disks together to make a grinding wheel, and used that. As you have already stated, and as Jeremy has just re-stated, it does have to be fairly accurate. Unless you are totally comfortable with attempting this fabrication, I would also recommend that you take it to a machine shop. I would hate to feel responsible if you should end up messing up that shaft. It is not something that most people would/should attempt. I have done this on several occasions. I have also messed up a lot of hardware during my life, in the name of learning how to do things. Just wanted to give you a few words of caution. If you still want to attempt it, I just remembered another way that I have accomplished the same thing, which I think is actually easier. I got the next size larger key. Then I widened the groove, while using the good side of the groove as a reference. I started at the end and checked the fit of the key as I went from one end to the other. This was to make sure I didn't get the slot too wide. Once I had fitted the key into the widened slot, I then used the grinder to thin the exposed portion of the key to the original width, so that the mating part could again slide over it. This takes less grinding on the shaft, gives you reference surfaces to work from, and still allows the keyway to be cut on the opposite side if you mess up.
portuncia Posted June 15, 2006 Author Posted June 15, 2006 Thanks for the response. I am pretty mechanically inclined so I believe I can do it. My take is... if a new shaft is around 60-70 bucks, taking it to a machine shop requires me pulling it apart so I might as well attempt the retro myself, if I screw it up I have to take it apart and buy/install a new shaft. I appreciate your help and words of caution, this site is great. I could easily become a diehard collector like you folks. Jeff
BigSix Posted June 16, 2006 Posted June 16, 2006 jlasater: Is an "end mill" the same thing as a "broach"? I've never seen either one, but I'm curious. I'm even more curious to know if the machine shop would need to have the BGB shaft removed from the box, or could they do it with the shaft still installed in the BGB? I'm assuming not, but I'd like to make sure.... If it has to come apart, I'm definitely liking Rod's homebrew approach-lol. Rod: This was great! quote:If you still want to attempt it, I just remembered another way that I have accomplished the same thing, which I think is actually easier. I got the next size larger key. Then I widened the groove, while using the good side of the groove as a reference. I started at the end and checked the fit of the key as I went from one end to the other. This was to make sure I didn't get the slot too wide. Once I had fitted the key into the widened slot, I then used the grinder to thin the exposed portion of the key to the original width, so that the mating part could again slide over it. This takes less grinding on the shaft, gives you reference surfaces to work from, and still allows the keyway to be cut on the opposite side if you mess up. I have to try this because, like portuncia said: quote:My take is... if a new shaft is around 60-70 bucks, taking it to a machine shop requires me pulling it apart so I might as well attempt the retro myself, if I screw it up I have to take it apart and buy/install a new shaft. I can't believe I didn't think of it myself. I don't have a die grinder, per se. I have a Dremel, with a right angle adapter. Is your die grinder air powered? I also have a 4 1/2" angle grinde, which accepts .045" thick cutting discs, but I assume that would way too large a diameter to work with. Do you think the Dremel would suffice, or should I bite the bullet and get a die grinder, which I'd like to anyway? And can you recommend a good source/type/grit for the discs for the grinder? Thanks, Peter
HubbardRA Posted June 16, 2006 Posted June 16, 2006 Peter, An end mill is something like a drill bit, but it is designed to cut directly on the end of the tool. The part is mounted onto a table that moves at a controlled rate. The mill is brought down into the material much like a drill press, then the table moves slowly to the side to cut the groove. There are other devices, such as a horizontal mill that can also be used to cut the slot. A broach is made more like a file, being a straight part with cutter teeth on it. It is lined up in a fixture where the groove is to be cut, then as it is pulled in a straight line, the groove is cut. A broach is usually used inside the gear or pulley, where the mill or other device can't be used. The die grinder is basically a large dremmel tool. Mine is a Craftsman with 1/4 shaft and electric motor, about three times the size of a dremmel. They also make them to run off air. A dremmel tool will do the same thing, just a little slower. The 4-inch grinder with cut-off wheel will also work, but I will caution you on that one. It removes metal very quickly, and can jump on you and make a mess of the slot. Yes, I use mine for things of this type. I have also messed up quite a few parts from the wheel catching and jumping on me. I also have a nice scar on top of my left index finger from one of these grinders jumping and taking the very top off my finger. Be careful if you use these devices, especially if you are holding the part with one hand and the grinder in the other. Voice of experience.
Alpha8D Posted June 16, 2006 Posted June 16, 2006 The old fashioned way to cut a keyway is with a cape chisel. It's used like the stroking of an old fashioned reciprocation shaper, a little is taken off the depth each pass keeping the chisel honed sharp and tapping it forward. The cape chisel is U shaped and when depth is reached you either regrind chisel to square to get the corners carved out or perhaps you have a square shouldered cape chisel on hand. A file to finish up but not in the very corners. File corner is too radiused for that. I remember doing ONE like this, years go. I don't care to ever do another thank you but thought the method might be of interest. The above was done before the shaft was heat treated. If the shaft at hand is hard this method would be a real bugger.
JohnFornaro Posted June 17, 2006 Posted June 17, 2006 I'm a old carpenter, and have cut many a notch with a chisel, in the manner you have discussed above. It sounds like a very old fashioned technique. I like the historical aspect.
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