2.0 Ra is far from a mirror finish. The only means to remove 400 microns in a single pass would be to turn it. I typical ground finish would be closer to 0.4 Ra, but with 400 microns of stock to remove, would take multiple passes. Surface finishes of 2.0 Ra are easily attainable with turning. A...
Depending on the configuration of the part, an optical comparator might work. You could also use a CMM or a linear form tester such as the Zeiss Surfcom.
Thanks for all the valuable information. We are using 52100 and thru hardening to RKW 30N 77 Min.It's been our experience that each heat acts a little differently regarding the growth in length after heat treat, even in a well controlled heat treat process. Enough so that we need to perform a...
Does the reduction ratio of the raw material have any bearing on the rate of growth of a part in heat treat? For example, given a single heat of steel, one bar drawn to a diameter of 1" and one bar drawn to a diameter of 1/2". The 1" bar is turned to produce a part of .45" diameter as is the...
You'll be hard pressed to find ANY calipers capable of measuring +/- .0005" accurately. They may have that sort of resolution, but will never pass a GRR at that level. In the precision machining world I live in, calipers are not used on tolerances less than +/- .005". I'd suggest an indicator...
More important for Ford small blocks is to get a flywheel with the correct balnce weight. Ford used 2 different balance weights on the balncer and flywheel over the years, 28 ounce and 50 ounce. If you don't have the correct one for both the balancer and flywheel, the engine will shake itself...
I would think it's due to the fact that the spring in it's full extension position is somewhat nonlinear regarding rate. But if you start with some preload the rate is more nearly linear.
Coming from a machining and quality background, wouldn't it be better to find a way to stabilize the process rather than rely on inspection to insure good parts? Have yopu performed a capability study to determine whether or not the machine is capable of running the part with good control and...
Absolutely. The L1 checks the pitch diameter of the threads, which will change by 4x the plating thickness after plating. The L2 is probably not as critical, but the minor diameter will also change some due to plating buildup on the crest of the threads. The unplated thread form must be modified...
No. The cutoff length is the length over which the trace is evaluated. Generally the length of trace is made up of 6 cutoff lengths. Example: length of trace 1.5mm would have a cutoff length of .25mm. The cutoff length is generally selected based on the periodicity of the surface finish.
Craig,
Glad I can be of assistance. It's unfortunate that there is so much variation in the plating thickness, especially for class 3 threads. Could a plating that is more controllable in thickness be substituted for the Cad?
We run parts at pre-plate dimensions all the time. For external threads, the pitch diameter low limit is decreased by 4X the low plating limit, and the pitch diameter hi limit is decreased by 4 x the hi plating limit. This decreases the as-machined pitch diameter limits and requires a tri-roller...
