Setting up to test the rewired CNC Bantam and Probe Basic Lathe

Now that I've developed a ballscrew attachment for the JD TB3 tube bender, I need to prepare to get the new compts machined. This requires:

• Find suitable material for the 2 blocks., This should really be steel, as loominum isn't going to work so well, either in terms of strength or as a bearing material where it bears against the bender's arms. I seem to have a piece of 1" x 3" hot rolled steel of 190mm length. That's a bit shorter than I'd planned but I have little choice of material to start from. I can cut it into a 100mm length for the bearing bock and a 90mm length for the ballnut. I will modify the blocks in Fusion to suit the new reality.
• Cut the stock ready for machining. 
• Flash up some lathe tools in Fusion. Currently, most of the tools in my library are for the Tree ie LH tools, whereas I need RH tools. So to start with I will create a 25.5mm drill, a CCMT060204 tipped boring bar and a fairly conventional RH turning tool with DCMT11T304 insert, while I'm at it.
• Create the toolpaths in Fusion using the new tools.
• Export the tools from Fusion as a JSON file and import them into the PBL as the tool library.
• Import the g code for the boring operations into PBL.

I don't intend to do the predrilling as a CNC operation, as I will be using a tailstock mounted drill for that. Similarly I'm not sure I can be arsed to face off the front of the stock afterwards. So this will simply comprise the rough boring and finish boring operations.

Here's the modified bearing block. It's a fair bit thinner than before and instead of having pillars sticking out on top and bottom, I will insert short collared spacers or shouldered screws.

Similarly, the ballnut bracket has shorter pillars.

There should be enough info here for me to set up the machine:

Here's the boring bar setup:

And the turning tool:

For the CCMT060304, I will use 80m/min surface speed, 0.1mm per rev feedrate and 1mm depth of cut. This is a slender boring bar, albeit carbide, so I've erred on the cautious side.

For the DCMT11T304, I will use 150m/min surface speed, 0.1mm per rev feedrate and 2mm depth of cut. Or I would if I planned to use it here.

Note that there's no actual (internal) boring operation as such. Instead, you select Profile Roughing and Profile Finishing and by selecting the appropriate features you define a boring operation.

FFS, some of the Fusion turning toolpaths are a rite of passage. I struggled to get this done but finally found that turning "Rest Machining" off allowed the thing to generate non-empty toolpaths, which is quite helpful. The rough boring and finish boring operations, which make use of a pre-drilled 25.5mm hole:

The (not used facing operation):

The g code for the boring operations:

%

(3001)

(BRG BLOCK)

N10 G7

N11 G18

N12 G90

N13 G21

N14 G28 X0.

N15 G28 Z0.

(PROFILE ROUGHING2)

N16 T12 M6

N18 G54

N19 G97 S3500 M3

N20 G95

....

....

N127 G1 Z-16.9 F0.1

N128 X59.9

N129 X57.9 Z-15.9

N130 G0 X0.

N131 Z5.

N132 G97 S3500 M3

(PROFILE FINISHING2)

N133 M5

N134 M1

N135 G97 S2000 M3

N136 G95

N137 G0 X0. Z5.

N138 G96 D2000 S80 M3

N139 G0 Z1.014

N140 X58.922

N141 G1 X59.172 F0.1

N142 X62. Z-0.4

N143 Z-17.

N144 X50.

N145 X47.172 Z-15.586

N146 G0 X0.

N147 Z5.

N148 G97 S2000 M3

(PROFILE FINISHING3)

N149 M5

N150 M1

N151 G97 S2000 M3

N152 G95

N153 G0 X0. Z5.

N154 G96 D2000 S80 M3

N155 G0 Z-15.986

N156 X46.922

N157 G1 X47.172 F0.1

N158 X50. Z-17.4

N159 Z-25.4

N160 X46.

N161 G0 X0.

N162 Z5.

N163 G97 S2000 M3

N164 M5

N165 G28 X0.

N166 G28 Z0.

N167 M30

%

Let's get the stock set up in the 4 jaw and import the g code into PBL.

Ooof, those jaws are in the way of the boring toolpath. That's what happens when you allow The Stupid Fat Bloke to get ahead of himself and set stuff up before thinking things through. And it was all dialled in at this stage of course.

That's better. With a 4-jaw chuck you can remove 2 of the jaws and swap them round without removing the work, then do the same with the other 2 jaws. So it remains true and now has a helpful gap between the rear of the stock and the chuck and jaws. This method costs less in terms of inserts, carbide boring bars and chuck jaws.

Once I've imported the g code, I may be forced to actually machine this bearing block.....