19 Jan 2019

Something big and heavy is headed this way. Yeah, a mill is half way across the country, hopefully one that I won’t think about upgrading for a very long time.

Some background: I’ve gone back and forth on getting a mill for decades, weighing the small (which fit well into a crowded garage) and low-priced import bench mill/drills, against knee mills, and those against enormous, stout, and very used Bridgeport-sized machines. Long story short, I wanted the impossible: a small, high quality, inexpensive, and reliable machine—it doesn’t exist. Proponents of Big American Iron, who always seen to know of deals nowhere near me or deals I missed, insist that anything short of US-made machinery is junk. As is written in the book, if this machine was in a factory where time is money, I might agree with them, but that’s not me.

Buying an old, well-used large machine is not an guarantee of success, and I don’t know what I’m looking at. I get the point about them being more rigid, but that doesn’t guarantee accuracy or repeatability if the ways and/or bearings are shot. The big picture purchase price includes fixing the worn parts (who’s going to make the repairs and what does that cost?). Buying something used means looking at it in person, and most are far away. Then there’s tax and the expense of moving a 3000 lb machine to where I want. Since I don’t have the space for a full-size machine anyway, that doesn’t matter, narrowing the choices to smaller (non-domestic) units.

So many times I nearly bought a bench-top Chinese mill, figuring something was better than nothing, but I just couldn’t. There are so many negative posts about them that I figured there has to be something to that and they should be avoided.

There’s another aspect of this as well, at least as important as the machine itself. Due to the expense, this needs to be a one-time purchase.  I don’t want to risk spending $$$$ on a beat-up or low quality machine only to find out it’s terrible, then have to explain to the wife why I have to dump more money into it, or worse, get rid of it for half what I paid, and then spend double that to get a good one. I ended up compromising between American and Chinese and went Taiwanese. The mill is available in several versions: switchable belts, variable speed, and single or 3-phase. The variable speed version is mechanical, meaning that the speed is set by an adjustable-radius pulley. I’d have gone for that one but it’s $800 more and has a lot of moving parts. Because 3-phase is also available, however, a variable-frequency drive (VFD) can be added, resulting in a much wider speed range, more torque, and it’s also much cheaper, but does require substantial setup. The manual for the VFD alone is 98 pages of dense settings, so there’ll be time spent getting that going, and making a small box containing the controls (speed, fwd/reverse, start/stop, and bump).

The unit is basically a baby Bridgeport and weighs 1500 lbs. so I don’t want to move it any more than necessary. Also, being a baby Bridgeport means that at normal working height, the table is (said to be) fairly low for anyone taller than maybe 5′-8″. For those reasons, a wheeled stand will be made to adds roughly 7″ of height. While it’s tempting to go higher, the thought of having that much weight that high up makes me nervous. The large iron-wheel casters will give it mobility, and it’ll have three (yes, three) leveling pads. The thinking is that four pads won’t spread the weight evenly; there’s always going to be one that has more, less, or even no(!) weight on it, distorting the machine base to some degree. Yes, having three is less stable, but the idea is to crank the pads down so that they just remove weight off the castors. That way, if there’s ever any tendency to tip, the wheels are there to stop things. The plan is to use the engine hoist and lift it off its pallet, straight onto its stand, where it’ll live from then on.

Before it arrives, there’ll be a massive garage cleanup, pulling out everything and probably tossing out or giving away a bunch of stuff. The final layout will probably be slightly different than the drawings from the last blog entry. I’m also going to try something which may or may not go well, as the new layout requires a slightly smaller storage shelf. The one I have is huge, 8′ high, 8′ wide, and 2′ deep, and heavy duty. I just hate to throw it out and then spend more on a smaller unit that probably won’t be as good. The plan is to disassemble this one, cut the frame down 24″, and reassemble it. Either I’ll congratulate myself, or get pissed if it all goes wrong or takes too long. We’ll see.

Lastly, I ordered a manual mill because I can’t justify the expense of CNC. Plus, some of them don’t even have handles! About the only thing I think I’ll miss is the ability to mill curves or circles, but again, the number of times that’ll come up will be few, and virtually everything I make is a one-off, nothing requiring “production”. Because, if I just have to do something requiring a CNC, I know a buddy with a $25K machine 🙂

31 Dec 2018

First off, happy New Year!

So having just reached a big age milestone, a thought bouncing around is, “what am I going to do with my time if/when I retire?” The telescope is useful in that respect because it’ll be something to do when I don’t have to worry about getting up early for work. There’s also a growing itch to start planning for a better-equipped shop where I can make whatever strikes my mood, retired or not. The lead contender right now is getting a mill of some sort. With a mill and lathe, just about anything can be fabricated. The lathe has been indispensable, but there are many things that only a mill can do, and without it, quality suffers. Take drilling several accurately-placed holes…

One of the most annoying things that’s been a bother for, oh, forever, is the drill press—the bit “walks”. One of the worst examples happens when drilling holes through square tubing. Mark one side accurately, drill that hole, and then, “since it’s accurately located, I’ll just continue drilling through the opposite side”, instead of flipping it over, measuring a second time, and drilling that hole separate. For whatever reason, the drill always emerges off-center, enough that on suspension brackets on the car, the part had to be tossed out. I know what you’re going to say: center-punch the hole (I do), use a center drill (I do), don’t bear down on it (I don’t), and check that the table is square to the arbor (it is). It may be radial play in the drill press arbor, or maybe all drill presses do this to some degree. It does it even with single holes as well, I can watch it walk slightly as it initially starts to bite. It’s okay for ordinary drill work, but not for anything requiring precision.

In addition to accurately locating holes, a mill is perfect for cutting accurate slots (instead of drilling holes and using the jigsaw to connect them, which is hard or impossible in tubing), being able to face blocks of metal and know it’s flat, and on and on. And finally, closely related to accurately locating holes is having a Digital Read Out (DRO); once you use a lathe or mill with one, you won’t want to go back. DROs also have built-in smarts for things like tool diameter offset, locating holes spaced evenly in a line, or X number of holes on a diameter. Sure, placing holes manually has been done forever, but the DRO is such an enormous help, it’s also on the list.

This brings up the old problem: where does it go? My “shop” is confined to one half of a two-car garage—with both cars in the garage, which makes working on anything far more challenging. Backing out the cars only helps temporarily since the large equipment stays put. Because of this, adding anything to the shop is a struggle, and especially a mill since a 30″ bed typically needs about 72″ total lateral space due to it moving both left and right. Because of that, its envelope is best suited to a corner, if I had one. Messing about on the computer with paper dolls produced these floor plans. The second one fits better, but counts on the mill bed to project under the band saw table; hopefully that’s not wishful thinking. Regardless, it all starts with a big cleanup, as there’s a lot of stuff taking up space but probably isn’t worth keeping around. It also means giving up half my storage space, but it isn’t that bad since 3/4 of it has sat unmoved for years.

The proximity of the band saw to the grinding center works since the grinding center is lower than the band saw table. As for what mill I’ll end up with, who knows. It all depends what pops up, and while everyone always says to get a used Bridgeport, they’re so old, tired, and huge, that getting one up and running could be a long and expensive endeavor, one I’m not really wanting to get into now. The reality is that it’ll probably be a smaller bench unit, but we’ll see.

9 December 2018

Some updates:

 “Why has it been so quiet?” While Midlana builders continue to make progress, and I keep a close eye on them for support, I haven’t been driving my car much. Why? It’s because I’ve been distracted by a number of things, including telescopes. Back 25 years ago, I built a 10″ f6 Newtonian, used it a while, then got distracted by, of course, cars. Fast forward to now and it’s been sitting in the garage this whole time under a tarp. With the grandkids growing, my interest has been rekindled, but the mirror is in sorry need of being recoated. Me being me though, I see it as a chance to built a larger one, and of course one thing leads to another…

Speaking of being distracted, this weekend was a trackday at Fontana and for several reasons I didn’t feel like going. My brother went and, well, now he knows how I felt a couple years ago. He went out for one session and all was fine for about 20 minutes, then the LS-3 started running rough. The water pump/alternator belt had broken and the engine overheated. No problem, he had a slightly shorter spare and installed that. Went back out and things went from bad to worse. The slightly shorter belt apparently bottomed out the tensioner, overheated the bearing, and the pulley disintegrated, and as it flew off, it took the drysump belt with it, so in about two seconds of running without oil pressure, the engine was junk and his day was done. If there’s a good side to this, it’s that an brand new LS-3 with a factory warrantee is “only” about $7000, and the external oil lines, drysump tank, and pump, are fine, ironically because they failed first. He’s bummed, but not as bad as when I blew up my engine!