Monday, January 18, 2021

First attempt at shrink fit tool holders

The eventual goal is to have these for all my tools so I can preset tool lengths and never swap ER collets.  This one was machined on a kind of sketchy lathe at work, so that's my excuse for the .0005" runout.  In the future I'll bore them out in the mill spindle.

Technically the tool length depends on how tightly you fasten the collet nut, so I did some "blind" testing, tightening the nut without looking at the dial indicator.  Seems pretty repeatable:

Sunday, January 10, 2021

Pretending the mill is a lathe

 A quick experiment in doing some turning on the mill.  The mill is in "TCP" mode, so I can jog it in work coordinate system rather than machine coordinate system, and turn a taper by jogging in the WCS Z axis.  Material is 17-4 PH stainless, 5000 RPM, .3mm DOC.

This clip shows how the mill is moving in both the Z and Y axis to make an 8 degree taper (indicating against an ER collet), but I only have to jog in Z on the pendant:

Thursday, January 7, 2021

Thin Part Fixturing

Using the super glue and blue tape trick to fixture some large (relative to the mill), thin parts.  I normally used double-sided tape for stuff like this, but didn't have any on hand.

Tape applied to stock and fixture:

Clamped while the super glue is curing:

Lots of Y-axis exercise profiling some semi-circular grooves:

Saturday, January 2, 2021

Gourd Ukulele Modifications

Finished making some long overdue fixes to the gourd ukulele.  Originally the neck was too thick and it had too much string action.

Tuesday, December 29, 2020

Gear Pump Closed Loop Pressure Control


Using a leftover pendulum motor controller, Moog brushless motor scavenged from the Media Lab years ago, and gear pump from ebay to play with closed-loop pressure control.  Pressure plotted on the computer screen (and shown on the gauge), pressure setpoint stepped up and down, and a needle valve used as a variable load.

Internals of the gear pump:  Food-grade, stainless body with PEEK/CF gears and bushings:

Monday, December 28, 2020