Ray you do some very interesting jobs. I have some questions on the wire line gage how do you get the starting center point? Do you get bar chatter with the larger bores? If not what are you doing to control the chatter. It appears that you are running a 2in. bar, atleast that is what Hofmann site states. How good is the facing tool you have there? I have one that I am not happy with what so ever. I can face quicker by feeding tool bit out and do not feel this should be the case. Thanks for any input. Jim
Jim,the wire fits into the support bearings.You just adjust the bearings to the datum you are using as you would if you using a bar to do your alignment.Go back a bit and there is a pic of an inside mike and the wire.
Chatter is usually a product of what you are mounted to,what you are cutting with,how rigid is the bar and how well it is supported. The Hofmann bars are made out of pretty good stuff and we have no trouble with removing metal using heavy cuts and plenty of feed. If you are hooked up on a light bucket that tends to flex you can add a bearing or stiffen the set up with a temporary brace tacked on.
Our 180 facing head I limit to taking 40 or 50 thou off at a time. I usually use it on faces 6 inches up to 14.A welded face usually comes of in 3 or 4 cuts.On small faces I often plunge face like yourself if its on something that don't matter if its perfectly flat. Make up a carbide tool and you can really peel some metal off but its limited to smaller faces.
With the 270 mm facing head you can work it hard.On faces from around 10 inch up to 36 you are able to take serious cuts and also bump the feed rate up to 40 thou a rev if you want a course finish.Have a look here at an old page of mine.The only pic that won't enlarge is the big head cutting an 850mm face.
Sorry about not being able to see it properly but you get the idea.
http://plb.iinet.net.au/jobs.htm