Al, In order to keep the tapered bore perpendicular to and concentric with the pitch dia. I'd true it up in a lathe and taper bore the pulley.
Dick Z
What is the normal or common way of cutting this taper in a pulley? Reamer?
http://www.cnczone.com/forums/showthread.php?t=44524
Al.
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CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Al, In order to keep the tapered bore perpendicular to and concentric with the pitch dia. I'd true it up in a lathe and taper bore the pulley.
Dick Z
DZASTR
Thanks!
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Hi Al, the only really accurate way to mount a taper bored pulley to a shaft is to set up the pulley in the four jaw chuck in your lathe and bore it with the compound slide set over to the angle.
This will guarantee the pulley runs radially and axially true.
There is no other way.
Just don't bore too big or the pulley will go too far up the taper.
Start testing the taper fit when the bore is halfway there and adjust the compound slide as required.
At the same time, while it's set up, you can plane the keyway in the bore with a boring bar on it's side using the saddle handwheel to plunge it in and out, making sure the keyway is marked out and on centre.
I use a small jack under the chuck with a wood pad while planing keyways to prevent the chuck from turning.
Ian.
Now, there is always some other way.
I did one on a motorized rotary table on a mill, I did not have a lathe available. The taper was 20 to 1 per side so with a 3/8" ball end mill just raise the Z 0.020 and move out 0.001 and let is go around 2 turns.
Benefit was a perfect angle without messing with a sin bar and indicating the compound slide.
Scallop height was 0.00027" so a light sanding and it was every bit as good as you could get on a lathe as far as fit and run out. If done on a CNC I would have used smaller Z steps.
Hmmmmmmm, and Hmmmmmmm again. just goes to show you the old guard have a lot to learn, all of these new fangled gadgets.
I wonder how many people would get it right first time.
BTW, how would you cut the keyway?
Hee Hee, just trying to be clever, I know there must be a dozen ways....
Actually, cutting the keyway while the job is set up after boring will ensure that the key is dead parallel to the axis of the bore, which will ensure that the key will not deflect the pulley if the keyway was cut as little as .01mm out of line.
Ian.
Hi Andre'B, just reread your post, I take my hat off to you, didn't realise that the rotary table and the mill set-up was not CNC.
So, moving the spindle .020" and the table .001" is a pretty neat way of getting the angle at 1:20 with just a conventional mill set-up, using a motorised rotary table of course.
Which leads on to say, who needs a lathe anyway LOL.
Ian.
Thanks:
When I got the mill (RF-30) I also got the 8" rotary table. At the time the only lathe I had was a little 6" Atlas/Craftsman so I mounted a lathe chuck on the rotary and rigged up a variable speed motor to turn it, figuring it could do some larger lathe type work. Works OK but it is slow and the finish on the parts does not look right.
Biggest part it has done is true up some 24" wood (MDF) wheels for a bandsaw.
Do not have any pics of the machining op but here is a low quality pic of the wheels on the sawmill.
Hi Andre, as they say, when the devil drives then needs must be.
I quite applaud your methods, I've never let an occasion when I was able to adapt a machine to suit a project deter me.
The very first milling "machine", I had was a 1/2" Atlas bench drill with a South Bend lathe saddle turned upside down and bolted to the base to form the X Y slides.
BTW, is the RF-30 mill the one with the round column?
I can't say I was very impressed with the rigidity of the head even with a 1/2" end mill in steel.
If that's the case I'd definately fit cross braces to the head and down to the base to dampen the flexing while milling, similar to that used on horizontal mills.
Ian.
Hi Geof, Tedious? I thought he was a Roman gentleman, yeah I know what you mean, but if it works in the end so what, not the best way to do it but it works.
When I was apprenticed in the 50's we had a couple of friends who built a beach type buggy using galvanised pipe for the chasis and a two cylinder air cooled water pump engine coupled to a Land Rover gearbox they "found" in the company's reclamation yard.
They had a lot of trouble keeping the back wheels turning and it turned out that with their limited knowledge of engineering they had just sandwiched the wheel flanges between some large nuts and washers on the rear shaft, and it was this that kept coming loose.
So being the "experts" mechanicaly wise, as we were second year appies and they were just high schoolers, we were challenged to solve the problem and set about chiselling a keyway in the shaft ends and the wheel bores, using just a 2lb hammer and a grooving chisel along with a couple of files.
Needless to say we got a couple of keys to eventually fit after much filing and fitting, but it worked.
That was tedious, worse than Manual Labour the Spanish chappie.
Ian.
Here is another way to turn a taper on a lathe.
Thanks, I treat that as a compliment.
Sounds like I should have contacted the patent office before posting the picture.
I knocked the setup over Easter as I had 160 pieces from 3/4" steel bar with a taper to make. I also have an ongoing order of 1500 alloy pieces which also need a taper so a thought it worthwhile.