48Doc:
Thanks for your appreciation of my idea. I do not know how much you spent on the lathe, nor do I know what your capabilities for steel fabrication are, aside from the big question of: "how much time do you want to spend/have available for getting the lathe ready to run ? "
The most recent countershaft I built was a kind of "built on the fly". I made a steel skid base for the camelback drill (top heavy machine), with enough space for mounting a countershaft. Once the drill was mounted on the skid base, I then took some dimensions for what would work for the countershaft structure. I shopped on ebay for the pillow block bearings and got the big (14" diameter, I think) vee pulley from "Surplus Center" in Lincoln, Nebraska. The skid base and countershaft structure were fabricated out of hollow square and hollow rectangular structural steel tubing ( all 3/16" wall), flat bar, and 2" x 2" steel angle. Some was scrap or leftovers from previous jobs, some was steel I ordered new from the local steel supplier. I have my own little design features when I build these sorts of things. I like to make tapped pads on the square structural tubing to mount the pillow blocks and motor rails (for tensioning the vee belt to the countershaft). I weld 3/8" thick x 2" wide A36 (structural steel grade) flatbar to the hollow tube using stitch welds. Stitch welds are plenty adequate for strength, and there is less distortion from the welding. No need to run continuous welds as these would tend to warp things. I am a product of the times I 'came up in', so about 99 % of the welding I do in my own shop is stick welding (SMAW), DC, using either E 6010 or E 7018. I like the old E 6010 (a 'fast freeze/digging' electrode) as it is great for tying in a root pass or 'keyholing" to really 'burn in' a root pass. I did buy a new WEG 3/4 HP farm duty motor for this drill. The countershaft itself was turned from 1 1/2" diameter hot rolled A36 steel round bar.
I generally avoid using cold rolled steel. If I am going to be turning different diameters, why pay for something finished to a diameter I do not need ? If I am milling keyways (assymetrical features or discontinuities), cold rolled steel has a nasty habit of warping. Machining deep into cold rolled steel releases 'locked in stresses', and post machining warpage is a common occurance. A 36 steel is a bit stronger, and being hot rolled, has less locked in stresses.
The countershaft flat belt pulley needed to be wide enough for a 2" wide flat belt to move on/off the tight and loose pulleys on the drill's bottom shaft. I found an old tractor belt pulley (maybe off an old Case tractor). It is the right diameter and about 6" wide. I machined the countershaft, milled the keyways in it, and mounted the pulley on it with a well-fitted shaft key. Used the countershaft as the mandrel to turn the pulley in my LeBlond lathe. Took a skim cut to get rid of the crown on the pulley, since the belt will be shifted along this pulley when going from tight to loose pulley or vice-versa.
The beauty of wood pulleys is they can be made with materials at hand. The old backwoods trick is to use a sprocket with a keyed bore bolted to the wood cone pulley. This gives a steel hub, and through bolts pull the wood cone pulley tight together with the face of the sprocket. You can use a smaller sprocket with the same shaft bore on the small end, and through bolt with tie-rods (pieces of round steel rod threaded at each end for nuts). This gives you a steel hub at each end of the wooden cone pulley. Assembling the rough/oversized pulley on the countershaft, it can be turned to finished diameters using not only the countershaft as the mandrel, but the countershaft frame and motor drive to turn it. Freehand turning with a sharp wood chisel (if you do not have proper wood turning tools) on the pulley can be done using the assembled countershaft as its own wood turning lathe. A narrow wood turning tool to turn the steps of the cone pulley to required diameters and work some crowning onto them, and finishing with sandpaper as the pulley is turning will give a good end result.
I have a "Lux" band cutoff saw in my home shop. It was a yard sale find years ago. Made in Taiwan, a light duty machine. When I bought it over 25 years ago, I figured it might last a few years and I'd get a heavier/larger capacity band cutoff saw. That little saw, with a new motor along the way, has been soldiering on and cut a lot of steel and other metals. An angle grinder, DC stick welder (I use an engine driven old Lincoln welder which lets me run the E 6010), and a drill press are the basic tools. A vertical milling machine to put in keyways and mill slotted holes to allow belt tension adjustments, or to mill welded bolting pads flat and into the same plane is something I am fortunate to have.
I like the old stick welding as I can run it any position, no shielding gas needed, and working outdoors if there is a bit of wind, no worries about losing the shielding gas envelope.No wire feeder to worry about 'birds nesting', simple as can be to setup and run with. I also like stick as I can really 'burn it in', particularly when running weld on structural tube. The structural steel tube, with radius'd corners, creates what is called a 'flaring bevel weld'. A bit more tricky to get the root pass to penetrate and tie in due to the geometry created by the radius'd corners. With stick welding, I run a good root pass and with a little 'weave', I can fill that flare bevel neatly. I am fortunate in that over my career, I was around a lot of welding done by the heavy construction trades and in powerplant maintenance work. As a young and green engineer 50 years ago, I was anxious to learn, and the pipefitters, boilermakers, and ironworkers were happy to teach me the practical ends of the business. In time, I became an American Welding Society Certified Welding Inspector, so tend to be tougher on myself than I might be on someone whose work I was inspecting. I inspect my own work as if I were to be inspected by some of the men I worked with over the years, really fine craftsmen. Similarly, when I do machine work, I use that same standard.
As a Professional Engineer, when I dream up something like a countershaft structure, I look at as I would look at any engineering project. Run a few calculations to be sure things will hold together and not buckle or deform (though I always over-design), think in terms of building it and erecting whatever it is by my lonesome, no extra pairs of hands, and think in terms of maintainability in the future.
I remember on my first powerplant project site, fresh out of engineering school, one of the pipefitters seeing me working hard to take field measurements and come up with some design for runs of welded piping and supports, kidded me. He said: "No worries, kid.... it's carbon steel... if you don't get it right, we can burn it out, clean things up with a grinder, and weld 'er back together a time or two until you git 'er done right..." I remembered that kidding remark. I also remember the pipefitter foreman. He was a kindly man with a son who was an apprentice on that job. He looked after me as well. I had designed some structural steel pipe supports for 12" diameter piping. Figured bending moments and all the rest of it, shear in welds, and had made my drawings. Handed them off to the pipefitter foreman. He looked at me and said: "Joe-boy, gonna show you something.... don't get mad... your design is good... now watch..." He took the safety cap from an oxygen bottle and used it as a template. He took his soapstone and draw a radius with it on an exposed corner on a piece of wideflange steel beam section of one of the pipe supports. One of the pipefitters took the striker hanging on his belt (on a clip made from 1/8" E 7018 with flux beat off it), lit a cutting torch, and burned off the square corner to create a radius'd corner. He then slicked it off with an angle grinder. "Looks a lot nicer, don't it ? Now nobody's gonna find that corner the hard way and cuss the SOB who designed it..." I thanked the pipefitter foreman and he gave me a wink and a pat on my shoulder. It is a lesson which I never forgot. Any steel I designed with exposed corners that could nail a person walking or working around it get radius'd. When I build a countershaft structure for my own shop, I radius exposed corners on the steel work. Makes a nicer looking job, and if I am folded in and around the countershaft to oil a bearing on the lower shaft of the drill or get the flat belt onto the pulleys, I am not going to get hurt if I bump into those corners.
50 + years in this work, maybe I am old fashioned in still using stick welding and making drawings and sketches with pen and paper and then taking measurements and making more sketches or 'cut and try' rather than using some software. The striker for lighting my cutting torch is on a belt clip made of E 7018 for me by one of the pipefitters on my first job, 50 years ago. My stainless steel thermos has a handle made of 3/8" diameter stainless steel instrument tubing, held on with hose clamps, made on that same job. Those were the times I came up in, and something like designing and building a countershaft and base skid the way I do it is a product of that experience.
