MadModder
Gallery, Projects and General => How do I?? => Topic started by: mzt on June 08, 2012, 09:36:25 AM
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Well, though next use of my boring head will (probably) be one for which I do not need to know the answer to this,
what is the correct way of doing repeated cuts without changing the settings of the cutter?
I mean, is it 'better' :
a) to raise the cutter while the spindle is running: You'll gain a nice spiral into the finished bore, dependent on the rasing speed.
b) to stop the spindle, then raise the cutter: that would draw a single straight line.
I tend to use the second option on finishing cuts, on roughing cuts .. I won't tell.
Much depends on the materials, and whether a line, however thin, would be acceptable or not. After the final cut, I can (usually) back the head slide a bit before rasing the quill.
Any big NO-NOs? Common ways, .. ?
Marcello
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PS. When boring on the lathe, I cheat without shame: just fit a DI to the apron and move the cross slide back and forth to the same reading.
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There is a 3rd option...
Do a fine cut in both directions.
This is the method I use.
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Is this repetition boring of similar parts with same hole size already in?
I am assuming theres a hole already in and each part the same size.
You may or may not be able to take much of a cut in one go if you need a decent finish.
Ideally some form of powered feed as spindles running.
What i do is use the boring head like a drill feeling for whats happening, done 138 holes last week that way.
I get the finish on the up stroke watching, feeling and hearing whats going on.
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Marcello:-
In the case for the cylinder for Simpson and Shipton as its an oval cylinder, just stop the spindle make sure the tool is clear of the bore and wind it back, also you'll be taking an interupted cut, I made mine from brass so didn't have much trouble from spring there was a little but, taking a fine finish cut sorted that out, don't try and work to a close size just make the piston fit whatever the bore comes out to.
Stew
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Yep! The Simpson & Shipton will be "the one I don't need to know the answer for". - I do tend to get a little cryptic in my writings, at times. Sorry. -
On this particular one, my plans were to make a gauge first, to ensure I've left no taper into the walls, then make the piston to size, as You suggested.
If I got it correctly, the rounded portions of the oval are not so much important as the linear ones.
As for the 'common procedure', I get rasing the quill while he spindle is turning is the method to use.
Thank You
Marcello