[ddmckee54]

Last night I worked on the rear wheels, got the design done and started it printing before I went to bed. I think it looks pretty good, but it's got two major boo-boos and one "that just doesn't look right" issue.

Major problem #1 was the depth of the pockets. I pocket the wheel openings and the screw holes at the same time, and must not have been paying that much attention to the actual depth. The wheel openings were a little shallow but still OK, but the screw holes were only 1-2 mm deep.

Major problem #2 was that the 12 mm hex driver didn't fit, it was too small. I have been using Simplify3D for years, but it seems to have an issue with internal pocket and bore dimensions. I scale the model in the slicer to 103%, this gives me a final print that is dimensionally accurate to the 3D model within a few hundredths of a mm, at least externally. Internal pockets and bores were always too small. I've found that if I manually scale the dimensions of the critical bores and pockets to 103% before I send the model to the slicer things work out much better. When I checked the model I had scaled every critical bore and pocket to 103%, except the pocket for the 12 mm driver - you just can't fix stupid sometimes. I'm beginning to wonder if S3D just offsets all the dimensions away from the core of the print when it scales? (Maybe there's an advanced setting that I haven't found yet to cover that?)

My just doesn't look right issue was there's too much gap between the tires. I had it at about 5 mm, which turns out to be too wide. I reduced that to about 2-3 mm, we'll see how that looks on the next print.

Speaking of the next print, I just aborted it. I noticed on the slicer print preview that there were only 2 perimeter walls between the screw hole and the bore for the locknut, there should have been room for 3-4 perimeter walls there. Turns out I had used the clearance diameter of the screw, instead of the minor diameter. At least the print had progressed far enough that I could check the fit of the 12 mm driver - fits like a glove. Oh well, fix model, re-slice, re-print.

Don