Archives for posts tagged ‘aluminum’

antenna ball

For the ham radio operator on my gift list…

antenna topper turned 9x20 lathe aluminum

After eyeballing the spherical shape using a mixture of cutting tools, rasps and files, I wet-sanded the tool marks off and polished it with red and green compound. Then I parted it off (pictured above) and drilled the mounting hole. I was going to measure the sphericity I got by eye but decided I’d rather not know.

milling machine modifications, part __?

In this minor modification I added a 50 lb. gas spring between the column and the head, meant to assist the Z-axis motor in lifting the weight of the head.

gas spring modification G0704 milling machine CNC

The stock part is a 50 lb. gas spring with ball-joint fittings, McMaster part #4138T621. I simply drilled a hole in the column (and tapped it for 5/16-18) for the lower pivot, but the upper pivot point wanted to be above the top of the head to allow for a full 12″ of travel. I designed and machined a simple aluminum part to extend the upper pivot point and mounted it to the head. While I was at it I also machined a nice little cap to cover the hole where the Z-axis crank was.
gas spring modification G0704 milling machine CNC

The backlash in the lead screws has been giving me relatively poor surface finishes, so I bead blasted these parts to even them out. I like the look, but the “toothy” surface really grabs onto dirt.

I was hoping to double the rapid speed I could get out of the Z-axis, but I didn’t quite make it… It went from 15 in/min to about 25 in/min, although I just bought some better way oil so we’ll see if that makes up the difference.

sneak peek! hot shop styles for 2012

This new milling machine creates a lot of tiny shards of aluminum. And apparently those are not good for a toddler to eat, so I’ve had to take steps to reduce the amount of aluminum chips I drag into the house from the shop. I think my solution is pretty stylish…

shop coveralls G0704 CNC mill

home made chuck key

This weekend I spent a lot of time in the shop machining parts for my CNC mill, and ran into a problem with the lathe. The four jaw chuck has these adjustment screws to move the jaws in and out, but I can’t find the chuck key needed to adjust them. They use an inverted key–it’s and innie, not an outie, like most chuck keys–and it’s almost impossible to adjust without that particular tool.

I had a leftover piece of steel rod, so I made my own:

9x20 lathe chuck key CNC machined

The ends were machined on the mill, clamping the piece upright in the vise. The shoulder was turned on the lathe (in the three jaw chuck!).

9x20 lathe chuck key CNC machined

I milled a socket into the other end for a 3/8″ ratchet, although the fat body makes it easy to turn quickly by hand. (I tried to knurl the end but I still don’t know how to knurl properly, so I just mucked it all up)

9x20 lathe four-jaw chuck

 

Operational!

CNC mill oiling system – plumbing

This is it… Grizzly Miller is in several large pieces on my bench, and the major upgrades have begun. First up, oiling system.

I made some refinements to the original concept and even built a tube-bending tool for the small brass tube I’ll be using.

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First step was machining the X and Y axis ways on the mill’s cross slide. I used a simple ‘S’ curve, programmed point-by-point into an old ProtoTRAK-converted Bridgeport. On the same machine I pocketed out some clearance for the X-axis ball nut.

Beyond these sketches, most of the design work happened on-the-fly. This is unusual for me, but I don’t have CAD data of the original milling machine parts, and tube fabrication turns out to be more sculpture than engineering anyway. I also bought a silver solder kit specifically meant for joining copper alloys, and tried a small test piece from some scrap material.

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I then fabricated the main brass manifold and mounted it to the cross slide. From there it was a matter of drilling end points in the cross slide and connecting the dots with brass tubing. Each of the four ways are connected with my modified banjo fitting, which allows for flow control adjustments. The two ball nut mounts were modified to accept an oiling tube, which will simply splash each ball screw with oil. The manifold will be fed by a flexible tube, which will attach to the little stub coming off the manifold.

The soldering process is messy and dangerous, but once the parts are cleaned up they’re really quite beautiful.

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The finished cross-slide assembly:

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The Z-axis got a similar treatment:

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More to come, stay tuned!