Re: Not Convinced
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Stan, I don't see where you've mentioned the type of bearing you have in your lathe. That can make a difference. I have what Robert tells me is the correct manual for my TH42, with Timken bearings. On page 10, under Bearing Adjustment, and referring to babbitt bearings, it says to loosen the bearing cap screws between 1/8-1/4 turn for speeds over 805rpm. When you're going back to lower speeds, or heavier cuts, you're supposed to tighten them again to maintain the correct bearing clearances. Next page says the Timken bearings are recommended for high spindle speeds for long intervals or for continuous production work with no adjustment. Page 47, on the machining of various materials, has a chart that shows 8 speeds of 164-2072rpm in direct drive depending on the pulley steps, and exclusive of the back gear. Back gear gives 8 steps from 28-345rpm. I have a pdf copy of the MOLO for the the Sears Master Craftsman lathe. It's different from the one for my TH42 in some places, but the info on page 10 is nearly identical. It doesn't have the chart on page 47, but a different spindle speed chart is on page 49 in both books, and lists the minimum and maximum speeds as 28 & 2072rpm. I think I'd figure 2072rpm as the max speed for either 10 or 12 inch lathes HTH! Bill in OKC
On Saturday, February 16, 2019, 6:41:56 PM CST, Stan Gorodenski <stanlep@...> wrote:
I think we all agree because I did take into account surface speed if you read my email. I am assuming the max rpm was set by Atlas to whatever it is by some considerations that have to do with possible surface speeds one might encounter. I don't think they just randomly selected a max rpm. Therefore, if Atlas had determined, which seems reasonable, that the max rpm for the 12" lathe is related to the max surface speed one might need, then to get an equivalent rpm for the 10" should be what I had suggested. However, aside from an argument of how to determine surface speed or equate rpm to surface speed, the main point of my post was to find out what the max rpm, as it came from the factory, is for my lathe. It had to have come out with this max rpm, whatever it may have been, for a reason. So, what was the max rpm as it came out from the factory? Does anyone know? 2486 seems too high to me. Also, can anyone confirm that the number of speeds for my lathe was 8 as it came from the factory, not 16? I think it was 8 based on what I said in my previous post and the image I had attached. Stan On 2/16/2019 5:22 PM, Dave Matticks wrote: Surface speed for cutting is only related to rpm whether turning, |
Bill in OKC too