Thread: Brain teaser- A well running job will not run the next morning.

Doesn't add up with morning vs afternoon, but the drills all from one 'lot' ? Possible bad grind? Cutting edge or back taper?

Originally Posted by Dualkit

Inconsistent material, a very common occurrence these days. I get certs on everything these days, and ask where it came from before I buy. I try to stick with the same brands if it worked well before. I also order more tooling than before as far as in different varieties. I have often been blown away when what tooling has worked well on a job the last 5 times it ran all of a sudden doesn't work, and drill and tap life go way down. Recently drills TINI coated cobalt drills would barely make 10 parts in some 4140 annealed. I was used to getting 100-150 parts. I went and tried some cheap black oxide coated HSS, the first one made 200 parts, I was blown away.

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

Originally Posted by DanASM

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

I would go with the TIN 118, but like I said on one strange batch they did not last. I had not been getting certs so no idea on any possible differences. I always buy the 4140 ANN from BMG Metals.

Are you just drilling and tapping ?, Are you tapping in inches per rev. ?
Maybe the machine is trying to drill in IPR also ?

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.

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.

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.

Originally Posted by BSCustoms

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.

Oh I can guarantee the coolant LOOKS perfect in the morning. I was thinking somehow the stuff that does the lubing in the coolant may settle up, down or...

quit waking up so early and start in the afternoon.

Originally Posted by metal-ica

quit waking up so early and start in the afternoon.

Now THAT could solve lots of problems!
(and maybe create one or two new, but ...???)



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Think Snow Eh!
Ox

Originally Posted by metal-ica

quit waking up so early and start in the afternoon.

another great suggestion!

Originally Posted by metal-ica

quit waking up so early and start in the afternoon.

And to make up for it, leave early

works for me.........

old boy at work says "start slow and taper off like a good turd"