Prototype Four is looking promising!


The assembled prototype with the adjusters installed.



I still need to order the button head cap screws. This will give the bearing a cleaner profile and sleeker look.


Closeup of how the adjusters push the bearing shaft against the linear shaft.




I can now make the hblb with only one set of adjusters thanks to a precision jig that was specifically designed for this application. Thanks Bill!



Castings as of 06.28.03

I love my cnc hot wire foam cutter. The TK-421 is a mindless robot that just keeps cranking out the foamies while I work on other things. I come back every half hour to put a new hunk of foam in, and the TK-421 keeps right on working. I don't have to pay it, feed it, or pay for its health insurance.


The new sprue technique works like a charm. I split a 1" square piece of foam so that there are four fingers on the end. These get hot glued to the foamy so there are multiple channels for the aluminum to enter the mold and the gas to escape. I then dunk the assembled part in drywall texture mix and vibrate the foam a bit so the plaster fills all of the voids. Then its on to the drying rack.


The drywall texture mix works so much better than plaster of paris. You can keep the bucket of mix around and it doesn't harden up. This is much more cost effective because it eliminates waste. Unlike the plaster of paris, the drywall texture does develop surface cracks, but the cracks don't seem to cause any problems in the casting.


The texture mix also falls off easier than the plaster of paris. In fact, just dumping the sand out of the bucket causes some of the shell to fall off. When I hit the casting with the water, all of the shell falls off and disintegrates.


You can see how the shell is already falling off just from moving the castings to the cooling area.


What great resolution! Even the sprues are perfect! Very cool.


The casting on the right was the absolute best part I have made yet. I assembled it and I didn't even need to put the adjusters in because the part was perfect! I will be installing the adjusters though to compensate for wear.