New U-Build Machine & Power Tools Catalog

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- Johnny Blackwell
  
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posted
19 years ago

Sat, Jan 24, 2004 2:42 AM

Of interest to metalworkers. New web catalog features: U-Build Metal Turning Lathes and accessories, Milling Attachments, Tool Post Grinders, Step Chucks, Form Turning Tools, Sheet Metal Brakes, Metal Former, Metal Bender, English Wheel, Hot Dip Galvanizing, Hybrid Shop Pantograph, Power Hacksaw, Compound Drill-Press Milling Table, Low Cost EDM, Power Oilstone for Edge Tools, Super File(No castings required) Portable Vise Punch, Arc Welding Gun, Abrasive Cut-Off Machine, Micrometer Work Holder for Bench Grinder, Steam/Models, Waste Oil Burners (to heat cold shops), Metal Melting Furnaces, Home Shop Etching & Electroplating, Much, Much, More! All U-BUILD! All Guaranteed. Visit catalog at

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and SAVE!

- B
- Bob Engelhardt
  
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posted
19 years ago

Sat, Jan 24, 2004 2:06 PM

From the "Machinists" section of

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"Boring bars provide a superior way to make round holes with true parallel walls, especially when mounted between centers."

Now I'm just a newbie, a babe-in-the-woods when it comes to machining, so can somebody explain how you use a boring bar _between centers_?? The only way that I can think of is to leave an island in the middle of the bored hole, for the tail stock center. Then clean out the island in a chuck. Do people really do that?

Bob

- B
- Bob Engelhardt
  
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posted
19 years ago

Sun, Jan 25, 2004 4:55 PM

Thanks for all the enlightenment. When I posted, I really thought that the quote was a mistake. Learn something everyday, hopefully.

But, about this turning between centers. I guess that you have some of the same problems as you have boring in a chuck. Particularly with long, narrow bores. In a chuck, the bar deflects and between centers the bar springs. Probably not as much as with a bar. Between centers the maximum length of the bore is 1/2 the distance between centers. In a chuck you can remove the tailstock and get a deeper bore.

About this problem of bar deflecting or springing: do they ever use an _internal_ follow rest? I.e., one mounted to the bar and bearing on the bore? It seems like that would be "just the ticket" for really long bores.

Bob