Hey Scott. In the photo above your post, you can see a heavy radial ball bearing, at the bottom of the spindle, that absorbs side loads. I checked the side play on the spindle with a dial indicator before I began cutting on that first side cover & then again later & it was staying the same. So I figure it's ok to proceed with caution. Very slow feed rates to keep side loads to a minimum. I've got a deal working on one of my bass rigs...fender jazz with duncan active pickups, carvin 600 w head & an avitar neo speaker cab...lateral transfer of funds to sherline for one of their vertical mills. Tim has one & speaks very highly of it's quality & features. I figure I've done gone stark raving mad over this stuff & I'm really digging the machining process & the mental challenges associated with it, so might as well do it right!
Going to read the table for run-out as a first item of business. Still have to dig through some more storage & find the magnetic base.
Quite impressed, considering the modest cost of these two items. Gear backlash on the table is almost zero & it has a good solid feel when rotated & the quality of the marking of the scales is impressive.
Mounted in the vice, it has X, Y axis as well.
My weak link now is the fact that I'm working under a drill press instead of a mill. One thing at a time, ya know what I mean, Vern? I can, at least, limp along slowly with what I have now & experience tighter tolerances on my quick change side covers.
The formula for converting FPM tp RPM is: Spindle Speed [RPM] = cutting speed (in inches) (pi*tool diameter). / Basically, find the circumference of the tool, divide the cutting speed by the tool circumference and that tells you how many times the tool will need to go around per minute to achieve the proper cutting speed. A larger diameter tool will go slower because it cuts more metal per revolution of the tool. ----------------------------- This is one of the better, I think, answers I've found on line. Since my feed rate is slow, I should be able to work with a slower spindle speed. I'm currently experimenting at about 1,000 rpm...with very light, slow feed cuts. Just trying to get a real world feel for what others, who are doing similar work, are using. You've mentioned in your thread some of the long days you've spent producing a particular part...
Good Idea, Michael. I may still have mine that I used for setting up my camshafts...sold a bunch of stuff when I retired. Tim, question...what speed do you turn your cutter bits for side cuts like what I've been doing?
Hey, Scott, good to see you. I'll have to have a mill eventually. I've got too many projects & the drill press is not designed for the side loads of milling so I feed it veeery slowly to minimize those side loads...I have much respect for my equipment. But I'm an old retired guy who's on a very tight budget, so I try to do my purchases in an order that will allow me to limp along while saving my lunch money for the next item.
Thanks for stopping in, Michael, good to see you. Thanks Tim. Sometimes I can live with the "looseness" of free hand work...sometimes not. I've been doing a lot of studying on this in the past few weeks. Found these items at Grizzly.
Even with my most careful layout & eyeball execution, I'm seeing small discrepancies in the evenness of the spacing on my cuts as I work around the piece. When I mock it up & set it in with the frame & rest of the build, it's not all that noticeable.....but I know they're there & it bugs the living heck out of me!! I'm committed to doing tighter work than that, for my own artistic edification!
With the rotary table, I can finish one cut & crank 36 degrees of rotation on the table & know that I'm cutting precisely in the right location.
The roadster seems to be on hold, as I'm being sucked deeper into this current build. So, I'm going to order these items in the next few days.
http://grizzly21-px.rtrk.ca/products/3- ... ble/T10053 The 4 jaw chuck is not self centering, each jaw is positioned independently, which means it's handy for holding odd shaped items like cylinder heads & water pumps & so on.
In keeping with my policy of honest reporting, it is now...quick change side covers, take 2.
I abandoned the first one, on the 8th cut of 10, when my clamping slipped, allowing the bit to rotate the workpiece slightly resulting in the cut moving off to the side. Major bummer!! But not totally...I was not happy with the randomness of the spacing between the cuts...a result of eyeball alignment discrepancies.
I learned some stuff.
Can get an idea, though, where I'm trying to go with this. Bear in mind, that this first cut is only the first of several I have planned for the pieces.