I'm about to bore a 3.150" hole with a shoulder at the bottom for my locomotive journal boxes on the lathe. Does anyone have a picture or diagram of a boring bar that would be appropriate for brass. It has to be able to generate the shoulder at the bottom as well. I have one that was ground for cast iron that Harold V. suggested but now it is time to grind for brass. The internet searching came up really strong for commercial sites w/ boring bars and inserts but I want to do this without an additional purchase. Thanks for any help that is forthcoming!
HJ
Need a Picture of a Boring Bar for Brass
Re: Need a Picture of a Boring Bar for Brass
The same geometry you used for cast iron should serve you perfectly well for brass. If you find it likes to self feed, reduce rake, if there is any. Zero rake would be desirable, to control that problem. It is rather important that the tool be quite sharp, however, so if it was used for iron, refresh the cutting edge by light grinding. Make sure you don't have any rounded edges, as copper based alloys will skate instead of cut given the opportunity. That quality makes holding size difficult.
As far as facing a shoulder, simply keep the included angle of the tool less than 90°, so the tip of the tool is the "high point". That way you should be able to bore and face. I do that routinely, using a long travel indicator to reveal location of the tool.
Harold
As far as facing a shoulder, simply keep the included angle of the tool less than 90°, so the tip of the tool is the "high point". That way you should be able to bore and face. I do that routinely, using a long travel indicator to reveal location of the tool.
Harold
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