Greetings to all!
My name is John Herrmann. I live in Phoenix, AZ, and am a member of Valley Metal, the machinists' club founded by Marty Escarcega (also a member of this forum!) About a year ago I bought my DM2400 from Marty. My intention was to get familiar with CNC, and this looked like an excellent entry level machine. Marty had done a wonderful job of converting it to Centroid. If you look at any of Marty's DM2400 videos, you're looking at the machine I bought.

I retired some years ago from a lengthy career as a machine designer/builder at Hewlett-Packard. During the time, we were using a CAD program that has since morphed into CREO Elements Direct. Unfortunately, I can't afford their extravagant price. So all I have is the very limited free version. And it will not allow me to save anything in any industry recognizable format. FOOEY! So I've been searching for a good CAD/CAM package. Tried a couple (Alibre, CamBam, Fusion, etc.), as well as doing a bunch of hand G-coding. It's a bit of a slog, but I figure it's a good learning experience ... and my hourly rate is pretty low Almost all my CNC machining to date has been on various plastics (Corian, acrylic, Lexan, expanded PVC, etc.), though I've started doing a couple aluminum parts.

My initial "project" was a soap dish, made from scrap Corian. It's basically a 4"x5" workpiece, pocket milled to ?" depth, then north-south and east-west "streets" ?" apart, cut with a ?" ball mill to a total depth of 5/16" The little square "islands" that are left raise the soap above the streets and allow it to dry. I'd previously made these on a manual mill, and it's definitely not something that "needs" CNC. My goal, though, is to make at least one soap dish to fit my oval bathroom sink. It'll have curved east-west streets and radiating north-south streets. Definitely not something to try on a manual! And a PS - a special shout-out to Brian Lamb (Youtube monicker dmogbrian), who was using the mill before I bought it from Marty, and who wrote a sample G-code program for one of my soap dishes as a "demo" to encourage me to buy the mill.

Most recently, I've been a bit concerned with a hardware issue on my 2400. Whenever I'm doing anything like a slot cut (ie, cutting with both sides of an end mill), the spindle has been making the most distressing screaming/groaning noise. RPM, depth of cut, cutter diameter, and material seemed to have little or no effect. Couple nights ago I pulled out the spindle housing and did a careful check. Turned out the spindle had ~.003 or .004 of axial play. Not good. So I've taken the spindle apart and examined the guts. The spindle uses a pair of precision angular contact ball bearings at the bottom end, and a third one at the top. As best I can tell, some previous owner (NOT Marty!) had installed the bearings upside-down, so that none of them were riding on the angular contact surfaces! Holding a pair of the bearings between my fingers, I can get either zero play or lots of play, depending on whether I'm holding the "tops" or the "bottoms" together.

The bearings may well be OK, but I went in search of replacements. One local (un-named) bearing supplier quoted $388 for just one of the bearings! Then I tried Motion Industries (Phoenix), talked to Hillary Miller. She found the same bearings (FAG, Germany) for $166, but there was a 6 month factory lead time. Then she "went the extra mile" for me and found an online source (in England) that had them in stock for about $146. Needles to say, I went to the English website and ordered the bearings. Motion Industries didn't get any of my dollars this time, but they'll definitely be first in line next time I need a decent bearing or suchlike!

I've made detailed CAD models of all the spindle innards and plan to post these here, as well as lots of photos, part numbers, etc. as I reassemble the spindle.

That's it for now. Stay well!

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