Which makes sense, obviously. Who amongst us can say the we use each and every drill equally so that sets are a logical way to buy replacements? I own drills that have never been used, NEVER!
Harold
MSC has some screw machine drills on sale now. - Today's flyer.
Martin
Maybe your not working hard enough... ;-)
Regards,
Robin
Guilty as charged!! Yep, now that I'm retired I don't do much on the machines anymore. However, even when I was running the shop, some things gathered a lot of dust.
How you doing with your schooling?
Harold
Well, you just gotta brush yourself off and keep on trucken'. ;-)
Pretty good I guess. I was filing for six weeks (32 hours of filing per week). Now that that's pretty much done with we're working on the machines. I did some hard turning today with a cermet insert. Very impressive. Cuts the case on case hardened steel like butter (although must butter doesn't glow and spark when it's cut).
Not exactly interesting work beyond that, but all good things to those who wait.
Regards,
Robin
Those things are flat-out amazing. The co-worker who introduced me to them explained 'they're running correctly when the chips coming off don't *quite* ignite in the air.'
Jim
================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ==================================================
I know one thing, Harold. Unless you are in possesion of *our* level, that young whippersnapper is still hogging it. I certainly have not had my turn yet. Had a couple shelves to put up, man, it was tough! Coulda been a breeze with the right tool for the job. But since I did not have the right tool.............
michael
replacements?
Ha! I got no level, and I got no Cermet. If it weren't for grinding machines, I'd have no luck with the hard stuff. Looks like I've been left in the dust of the younger guys. Heavy sigh!
Aren't those shelves crooked? Sure looks like it.
Harold
Well, I didn't exactly mean it was me that got dusty, but then------(sigh)
You're getting training that was not offered to me, but then I didn't start in the trade as a toolmaker, either. You'll be much the richer for the experiences, although it may not look much like it right now.
Advancements that were not even available when I was actively machining. Ceramic inserts were there, but not all that reliable. Flat amazing, isn't it?
You should end up on top of the heap with your formal training. Guys like me got (job) specific training, and while we may have ended up well qualified in particular areas, we lack experience in others. Hopefully you won't end up the same way. Looks like you won't. Keep strokin'! Your only real worry is if there will be any jobs left on the North American continent so you can ply your trade. Giving any thought to moving to China?
Harold
aero-space/defense
introduced to
believe they
I do not know when spot drills were introduced, but in Goodrich and Stanley's book Accurate Tool Work they are mentioned on page 35 and a picture in figure 55. This book was published in 1908, I am quoting from the Lindsay reprint edition. I would say that spot drills have been around for some time, maybe not used much until the advent of CNC.
Jeff
Ha! That's nothing. I got a buddy that made himself a cermet milling machine; scraped in the ways with diamonds.
90 deg spot drills were used many yrs ago on screw machines (& still are). Think about it most all holes & tapped holes call out a 45 deg chamfer on the hole. Do you want to use two tools, center drill, then chamfer when one will do both? That's why there are left hand spot drills. On a lot of the B&S screw machines you only have two speeds so you run your high speed in reverse, spot, drill (left hand drills) then change to low speed (forward) to tap in (at the correct speed for tap), change to High reverse to tap out (also saves time on tap out) & finish rest of turning & cut off. I have 2 setup that way & the others I use for non tapping jobs.
A perfect example of one (me) having worked in the trade, but having been job-specific trained. While I've been aware of screw machines all my life, I've never worked with or around them. Thanks for the great report and explanation.
Harold
John Ings wrote in news: snipped-for-privacy@4ax.com:
Spot drills are used on CNC machines to drill a conical starting (spotting) hole so you can come back and accurately drill the now spotted hole with a regular drill bit without the tip of the drill walking off center. They are usually short chisel tip bits that do not flex.
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