TURNING BETWEEN CENTERS

[johnsonbarParticipant @johnsonbar]

In live steam locomotive building books by Martin Evans and Stan Bray, the authors show pictures of setups for boring cylinder blocks by turning between centers on a lathe. The boring bars that are shown being used have receptacles in them for a tool bit, and the authors mention adjusting the cutting diameter with shims.

My question is – does anyone sell such boring bars or do you have to make them yourself? I cannot find them in any parts distributors that I know of. If anyone knows of a parts distributor who has them, could you please post their name and internet link.

Thank You.

[johnsonbarParticipant @johnsonbar]

[JasonBModerator @jasonb]

It's usually a case of making your own that way you can choose the thickest possible bar that will fit in the bore and not have too much excessive length.

Hemmingway do a kit if you want but you should be able to look at the picture and make something up similar.

 

J

Edited By JasonB on 09/08/2012 18:51:35

[KWILParticipant @kwil]

Arrand make a between centres adjustable boring bar with a "Microbore" tm , adjustable cutter. Not cheap by any means but very accurate and easily adjustable. Arrand or Millhillsupplies

[Clive HartlandParticipant @clivehartland94829]

Biggest problem is not enough clearance between the cross slide and the center of the boring bar.

I made my own and it worked fine but as I said I had minimal clearance to fit the job to be bored through.

Clive

[Russell EberhardtParticipant @russelleberhardt48058]

I built one to GHT's design(The Model Engineers Workshop Manual by Geo. H, Thomas) but with the hole for the tool drilled at 40 deg. to the axis so that 1/16 of a turn of the 40 tpi adjusting screw moves the toolbit radially by one thou. It makes it dead easy to bore to size. The angled ttoolbit makes it easy to measure the tool bit radius.

Well worth the effort of making one for cylinder boring.

Russell.

[johnsonbarParticipant @johnsonbar]

Thank you all for the information. I visited some web sites that sell boring bars for turning between centres, the prices scare me (and I am fearless!). I have GHT's plans, but was wondering if anyone had other plans for making the boring bar that they were willing to share? GHT's design is good, but I was wondering if someone else had something better.

Thank You.

[Author]

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