Scraping of The Saddle On My 15" Sheldon

Where about is your shop, I live in the corner of 183, 620, triangulated by Anderson Mill Road, maybe we can hook up sometime.
Nez, The shop is a few miles south of you... near Uhland off of Hwy 21. Next time I get up north I will give you a call. I would enjoy meeting you!
 
I use the vee way and flat on the lathe bed. The lathe bed is nearly new. May have a quarter thousandth wear if even that. Got very lucky on this lathe.

How do you ensure that the vee ways on the saddle stay parallel to the top of the saddle? The vee ways might (and most likely do) wear unevenly. I can see how the lathe bed would be fine, especially out near the tail stock, but just using that does not ensure that the ways are parallel to the top of the cross slide. Or do you check that later with some sort of indicator setup? Nice work, thanks for posting.
 
Does it make a difference if it's not parallel? In my book, it doesn't.

I did check it for parallelism. It was out about .008" in the length of the saddle. And of course, most of the wear was at the headstock end of saddle.
When I rescraped the underside of the saddle, I scraped heavy on the less worn area at the opposite end of the wear on both the vee and flat. Once I did that, went back and scraped heavy in the middle for relief. After that, I started scraping to get good bearing at all four corners. Once that has happen, then I start scraping to get around 15-20 ppi in the bearing areas. Then I call it good. After doing all of that, parallelism was within .0015-.0020".

Again, how important is parallelism? I know all of the experts out there say it needs to be parallel. In reality, It could be 0.030" difference end to end, and it would never be notice in normal lathe operations. It's your discretion on how close you want to make it. And how much time you want to spend getting it there.

Ken
 
Ok just to be clear, I have not done this before so my question is aimed at understanding, not trying to be critical because at this point I couldn't scrape to 1 ppi let alone 20. I think the only problem is when you are doing something other than turning, like knurling or parting, when u want the tool exactly 90 deg to the axis of the lathe. I guess we are talking less than a deg off vertical so perhaps it doesn't matter.
 
It wouldn't matter in knurling. If off by 0.0025" in parallel, saddle is about 17-18 lg. I'm not going to go out and measure. That would mean about 0.00013" in 1" That would be zero effect on knurling. If it was .030" out of parallel, that would be about 0.0016" in 1". That still would not have any effect on knurling or parting or even boring. On boring, you generally set the tip of the boring bar up high if the bar is sticking out say 4-6" on a 1/2 or even a 3/4" bar. (I shouldn't have brought that into the discussion. Save it for another time.)
Ken
 
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