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| Experiment Engraving Machine Dials |
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| awemawson:
This barely qualifies as a project - just a bit of experimentation. I wanted to add a calibrated dial to the infeed screw of my Dormer 108 Drill Sharpener - later models have it and it's a relatively simple and worthwhile addition. So I just need to engrave lines and numbers around the circumference of a doughnut of steel. Recently having bought CamBam (very impressed for the money) I drew up a linear version of the scale from which to generate G code |
| awemawson:
Now available with CamBam is a 'plugin' that enables you to 'wrap' G code around a cylinder. You specify the cylinder diameter, the angle you need to wrap around, and it does the maths to convert all the (in my case) Y axis moves into appropriate angles for the A axis to move - (there are several programs 'out there' on the web that do the same). As original this plug in wasn't quite suitable in that it generated too many decimal places after the point (5), and embedded comments in brackets - neither of which are acceptable to my Heidenhain TNC355 control which chokes on more than 3 decimal places in metric mode. The nice author of the plug in tweaked it so the latest version on the CamBam site now has a box to tick to supress comment, and a selection for the precision ie figures after the point So now we need something to engrave. It just happens that I had a length of 2" 'hollow bar' amongst my 'come in useful' bits - so a slice was cut off, bored to 30 mm i/d and skimmed to 50 mm o/d |
| awemawson:
Now the eagle eyed amongst you will notice that I'm using a 3 jaw chuck - should really be a 4 jaw to get it spot on - in practice the mandrel run out was only a couple of thou, and this was an experiment rather than the finished item, so it was the three jaw :ddb: The mandrel set is rather nice - can't remember where it came from but was made by the Armature Manufacturing Co of Oldham - no doubt they don't exist any more :scratch: They have a taper sliding arrangement that expands and grips a hole in the part, and you press them in to expand, then tap them with a soft hammer to release. So it was duly mounted in the 4th Axis on the Beaver Partsmaster, a few careful setting made to origins and I had at it with my diamond engraver |
| awemawson:
Now it started off really nicely - sharp cutting - crisp engraving - then it all went down hill :bang: Turned out that I'd lost the tip of the diamond :bang: ... no spare :bang: So I decided to pull it out of the 4th axis - skim a few thou off and start again with my air turbine powered rotary engraver with a 90 degree carbide cutter running at about 20,000 rpm. This went ok but the engraving width is too wide and nothing like as nice as the diamond drag engraver produced - replacement diamond on order :coffee: |
| awemawson:
Now contrast that engraving with a bit I did as a test earlier - nothing like as nice |
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