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11-29-2020, 03:25 PM #21
Doesn't add up with morning vs afternoon, but the drills all from one 'lot' ? Possible bad grind? Cutting edge or back taper?
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11-29-2020, 07:26 PM #22
I am running an HSS 14mm drill in some 4140 annealed. I am having good luck but this is first article. I was going to get a cobalt drill maybe TIN coated. I feel like I read that it wants a 118* point and most cobalt drills are 130*-135*.
Would I be wise to stick with HSS? They have a parabolic cobalt 130* drill that looks good but I am nervous about the 130* point.
I do see a nice cobalt TIN 118* here https://www.mscdirect.com/product/details/55076897
Or this https://www.mscdirect.com/product/details/55085146
Here is the parabolic one. https://www.mscdirect.com/product/details/36335867
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11-30-2020, 10:36 AM #23
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11-30-2020, 11:44 AM #24
Are you just drilling and tapping ?, Are you tapping in inches per rev. ?
Maybe the machine is trying to drill in IPR also ?
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12-01-2020, 08:48 AM #25
id say fire the machine up and mix the coolant! ive seen many seperate and the pump just pulls water at first in the am. try to mix the coolant for 45 min then run it.
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12-01-2020, 09:30 AM #26
If the job repeats AND I buy sheared and edged plate again AND have this issue again...running the coolant for awhile before starting is something I would try. It would have been a head to head answer with two machines...one I could have mixed coolant and ran and the other just ran. Oh well...
Only doubtful aspect of that is when coolant did run out once...straw to tan then blue chips and blue drill before alarming out machine with a wiped out blue drill.
The issue I had was chipped, snapped or badly worn drills without a visible heat issue. At least not an issue with tell tale colored chips. Then again water would keep part cool enough to not produce colored chips, yet not offer the lubricity in a nasty cut...It brings me back to this is a may be the reason.
I guess I could set it up and run again one day. All the parts that gave me grief I tossed in scrap barrel. Maybe I'll setup and run...I'm starting to get curious enough.
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BSCustoms liked this post
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12-01-2020, 10:08 AM #27
you don't have to wait for this job to come back. just check your coolant in the morning then again at the end of shift on any job. see if shes talking.
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12-01-2020, 11:14 AM #28
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12-01-2020, 11:19 AM #29
quit waking up so early and start in the afternoon.
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12-01-2020, 11:32 AM #30
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12-01-2020, 03:54 PM #31
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12-01-2020, 04:09 PM #32
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Greg White liked this post
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12-02-2020, 10:27 AM #33
old boy at work says "start slow and taper off like a good turd"
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