I'm pretty new to this so I don't know if it's something I'm doing or of it's the
material. I'm making 4 screwless vice clamps. More or less like these;
http://littlemachineshop.com/Projects/Drawings/ScrewlessViseClamps.pdf
I bought 4 pieces of 1018 cold rolled steel 1.25" square x 2.0" long ( should have
have had them cut 1.5" long but that's my bad). Got'em squared up at about 1.18"
or so on the mill on four sides. One of them didn't seem to "cut" the same as the other
three and was quite a bit more out of square/dimension than the other three when I started.
By out I mean 4-5 thousands. Mentally I dubbed that piece my "problem child".
Anyway, once I got them square I started mounting them on the lathe with my 4 jaw chuck
to start wasting off material to get the length in the neighborhood of 1.6" or so. I could take
off about .025" at a whack with no problem, accept for one piece. Granted it was late in the
day and I can't be absolutely sure my "problem child" piece from the milling operations was
the same one that gave me so much grief on the lathe. That one piece on the lathe was really
NOT happy with more than about 10-13 thousands. Bucking, trying to if not chattering, all in
all not the same experience I had with the other pieces. I think they were all cut from the same
bar. I'm lucky enough to have a very close supplier so I can call in an order and go pick it up
within the hour. I did watch the last piece fall off the horizontal bandsaw when I went to pick
them up so I wouldn't think the first piece was from a different bar BUT it may have been the
first cut from THAT bar. Is it possible, or possibly common for the first inch or so from a new bar
stock to have different properties from material further along in the bar?
material. I'm making 4 screwless vice clamps. More or less like these;
http://littlemachineshop.com/Projects/Drawings/ScrewlessViseClamps.pdf
I bought 4 pieces of 1018 cold rolled steel 1.25" square x 2.0" long ( should have
have had them cut 1.5" long but that's my bad). Got'em squared up at about 1.18"
or so on the mill on four sides. One of them didn't seem to "cut" the same as the other
three and was quite a bit more out of square/dimension than the other three when I started.
By out I mean 4-5 thousands. Mentally I dubbed that piece my "problem child".
Anyway, once I got them square I started mounting them on the lathe with my 4 jaw chuck
to start wasting off material to get the length in the neighborhood of 1.6" or so. I could take
off about .025" at a whack with no problem, accept for one piece. Granted it was late in the
day and I can't be absolutely sure my "problem child" piece from the milling operations was
the same one that gave me so much grief on the lathe. That one piece on the lathe was really
NOT happy with more than about 10-13 thousands. Bucking, trying to if not chattering, all in
all not the same experience I had with the other pieces. I think they were all cut from the same
bar. I'm lucky enough to have a very close supplier so I can call in an order and go pick it up
within the hour. I did watch the last piece fall off the horizontal bandsaw when I went to pick
them up so I wouldn't think the first piece was from a different bar BUT it may have been the
first cut from THAT bar. Is it possible, or possibly common for the first inch or so from a new bar
stock to have different properties from material further along in the bar?