On Tuesday 30 October 2007 14:17:43 Jon Elson wrote: > Kirk Wallace wrote: > > Has CNC changed the way keyways are made? I need to make some keyways > > for my mill conversion, and I have no tooling so far for doing it. Since > > I will may be buying tooling, I want to explore the options in order to > > make the best investment. I actually prefer not having keyways and going > > with set screws on countersinks. Anyone have thoughts on this? Thanks. > > You can cut keyways on a lathe using the carriage as the power > source, the X axis to step the feed, and a hand-made "shaper" > type tool as the cutter. You want to shave off a pretty thin > slice each time as the Z axis usually isn't very strong. I have > done this manually on occasion, and even made internal splines > this way. > > If keyways were in it before, they probably had a reason. The > only really good alternative is taper-lock hubs. The Bridgeport > BOSS machines used them, for instance, on the axis drive > pulleys, and they worked pretty well. You could actually make > some taper hubs on your lathe, now that it is mostly working. > It is essentially a collet. You have two pieces that are bored > for the shaft on the ID, and tapered on the OD to match a taper > cut on the ID of the sprocket. Then, there is a plate that > allows small bolts to pull the pulley tight onto the collet > pieces. You also need a scheme to push the pulley off the > collet. Look in Grainger or McMaster-Carr's catalog (on line) > and see if they have a good picture of these. > > Jon
Basically, copy the Browning taper-lock hub idea, it works very well indeed for the higher horsepower stuff. Pix might be available on their web page. Its internal collet is keyed for the usual square stock key, but I've seen the idea used on go-karts 40 years ago where the individual drive sprockets on the axle weren't fitted with a key, so that the firing order of multiple engine setups could be set to alternate for 2, or at 120 degrees for 3 engines. Even w/o keys, they only slipped if the cart jock didn't tighten them in sequence enough times. These were 5.8 to 6.1 cid 2 stroke engines turning up to 17k rpm's, so the shock loads at the lower rpms were pretty high on the hubs, and equally high at the 8 to 10 teeth on the engine sprockets at the top end, stretching a #35 chain for each engine into junk in an evenings racing, at speeds in the neighborhood (both sides of it) of 125 mph. Booze & dynamite burners, depending on the track & gearing might have hit 150 occasionally. I burned some booze & castor for a while, but my converted bilge pump engine was all run out at about 120. It was a deflector head design, & they are all done at about 8k rpm's. The torque its rotary intake gave just couldn't make up for the rpm loss, but I had fun and went through way too much money doing it. -- Cheers. Gene "There are 4 boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order" -Ed Howdershelt (Author) ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
