Mill Upgrades – Spindle Motor Part 3

The new spindle motor and pulleys are finally installed and working (and all the gearing and oil is out of the head).

As you can see in the picture below, I ended up with two cap screws to hold the spindle pulley in place. This is because I did a poor job on the bore and the pulley had 0.020″ runout. I just added the second cap screw and got it to within 0.002″, which really reduced the noise level.

The next step is to run the spindle up in steps and see how the temps look. It’s currently running the stock bearings, but I do have replacement angular contact bearings that are good up to at least 8k RPM with grease.

After that I want to try out some commercially available pulleys as I put together the BOM and instructions for the plans I’ll be selling.

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The biggest benefit by far is the difference in noise level. It now makes 77 dB at 3k RPM, compared to 85 dB with the gears in place.

Mill Upgrades – Spindle Motor – Part 2

Running into many more roadblocks than expected on this. I missed some critical factors when planning the installation of the original motor and as such had to recut the motor mounting plates (which required reinstalling the original motor and all the head gearing), and I’ve been distracted by working on the air compressor.

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I finally got around to testing the upgrade VFD, only to discover that it’s throwing a ‘low DC bus voltage’ error, which probably means something inside is not working right. I couldn’t get it working again and a replacement is $1k (I paid much less for mine on Ebay, but there don’t seem to be any floating around there now). I confirmed the motor worked with my Huanyang VFD, but I don’t trust one of those enough to make it permanent. Also, the cast iron motor I have is crazy heavy (100 lbs), so both for ease of installation and Z-axis acceleration a lighter motor is a plus.

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I went out and bought a used Baldor EM3610T (3 HP, two pole, 240V, steel banded case) on Ebay, and had to wait a few days to find out which face mounting kit was correct (according to Baldor, the 35-1325GLD, the 35-1325 will work too but the color doesn’t match). Finding C-face kits can be a pain and I strongly suggest you buy a motor which is sold with it already installed, like the CEM3610T.

I also bought an LS (formerly LG) VFD from Wolf Automation. There are a lot of good options for cheap single-phase drives in this horsepower range, including Fuji and Delta.

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The motor and VFD have been tested and are working, just waiting on the face mount to show up. The VFD is currently running the original 1.5 HP motor. Once the new face mount shows up it’ll be time to pull the head back apart and mount the new motor.

Compressor Refurbishment – Part 5

Time to clean everything up. I pulled the rusty valves apart (after cleaning the outsides up), and they range from not rusty at all to very, very rusty inside.

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The inside and top sealing surface of the crankcase cleaned up. See that tub next to it? That sludge was inside before. Yuck. I’ve already cleaned off most or all of the old gasket at this point.

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Here’s what the old gaskets looked like (I mostly removed them with a razor blade and a plastic scrubber).

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Installing the new gasket at the other end.

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And all back together.

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After flipping it on, there seems to be some knocking in the valves and the hydraulic pressure is low. So a little more work to get over the finish line.

Shars 440V 4″ Vise Review – Part 2

Got the Haimer in the spindle and off we go. Note that nothing here is statistically significant and the equipment being used is really not the right stuff (a Faro arm, or at least a large surface plate and a good indicator, would be a better choice but aren’t available), so take the results as you will. This is good enough for the work this machine does, and to confirm I’ve spent my money less poorly than I would otherwise.

Jaw alignment: measured at 0.0005″ off over 4″. I got the fixed jaw flat, zeroed out the indicator on the left side of the moving jaw, and got the reading shown below on the right side.IMG_3098.JPG

Parallelism (to spindle): 0.0006″ over ~5″. The bed drops away on the side further from the spindle. I will admit that it’s just as likely this is the machine. I didn’t have a piece of ground stock to test it lying around.

Clamping displacement: 0.000″. Unclamped and clamped shown below.

I’m happy with it so far, time to drop in some soft jaws and make some parts.

Compressor Refurbishment – Part 4

Mounting the crankshaft on my little lathe turned out to be pretty straight forward: using my Noga indicator holder again, this time with the cheap Fowler indicator from my last post followed by a 0.0005″ B&S indicator, I got the rear main journal bearing  centered in the chuck. I then followed the same procedure to get the front main journal bearing centered in the steady rest.

The plastic sheeting is to keep the carbon in the cast iron from getting on the ways. In retrospect I should have use something hard, at least between the chuck and the follow rest, to make cleanup a bit easier. Still, no harm no foul.

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I’ve done long work a few times on this lathe (primarily drilling out aluminum paintball barrels for sizing inserts), and knew I’d need to add a modification to turn cast iron (because of the force involved). The original steady rest jaws are bronze with no rolling components. I added some small bearings with simple shoulder bolts into the jaws. Not my favorite solution, but very easy. I think it’s likely I’ll go back and make a set of jaws that supports the bearings on both side in the future.

The original shaft was 01.375″, I took it down to 1.290″.

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You can kinda see this in the above photo, but this makes it very obvious that the old center (which I used to mount the gear puller when I removed the pulley) is no longer centered on the new shaft. This should not be a problem.

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Similarly, the keyway is no longer parallel to the shaft. This could be recut on the mill, leaving a little unused slot on each end, but I decided to accept a shorter key in this case.

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I forgot to take pictures while making the spacer (made from 1.185″ ID, 1.375″ OD 4130 tube) and test fitting everything, so we’ll skip to putting the bearings on. I initially tried to hand fit them by putting them in the oven, but I guess the clearance wasn’t quite enough at 250°F, so I pushed them the rest of the way on. They slide around two tons of applied force.

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To be followed by some cleanup on the rest of the unit, then reassembly!

 

Shars 440V 4″ Vise Review – Part 1

I’ve gotten tired of the cheap vises I originally bought with my machine (both low quality Chinese or Taiwanese units), as well as the used double station vise I picked up off Ebay (which I don’t see a brand name on). I set out to find some new ones with a few goals:

  • Maximize density on the table.
  • Get ‘good enough’ accuracy. Most of the time I don’t expect my machine to hold 0.001″, and never better than that.
  • Minimize cost.

I started by looking at vises in general, but primarily 6″ and 4″ units. After screwing around in Solidworks a bit, I confirmed that there is really no way for me to fit more than two 6″ vises from any brand on my table without significantly reducing Y-axis movement. That’s probably fine for most of what I do, but I have some small parts I’d really like to be able to drop a lot of in these, so higher density would be nice.

Once I focused on 4″ units, it really came down to a few options:

  • Glacern
  • Shars
  • Quad-I

Quad-I is unfortunately out of business, but based on my findings on Practical Machinist and Ebay they made some stuff that would have been perfect. Probably would have been too good (and pricey) for use in the case, but regardless not an option.

Between the Shars and Glacern vises there were a few things to compare:

  1. Glacern offers matching bed heights, Shars does not. I don’t think this will be critical for me, but something to keep in mind.
  2. Price: Glacern $360; Shars $250 (plus shipping for both).
  3. Overall length: Glacern lists theirs as 13.2″ long, versus Shars at 13.779″ (I’m thinking they shouldn’t have listed that level of accuracy though…).
  4. Distance between jaws: both give dimensions with 0.59″ thick jaws, Glacern says 4.05″, Shars says 6.02″.
  5. Similar overall width: Glacern at 6.35″, Shars at 6.535″.

Both units take standard jaws (3/8″-16 bolts on 2.5″ centers); standard mounting dimensions (5.25″ centers); 2.25″ +/-0.0005″ bed heights; use the wedge & hemisphere type anti-lift jaw (Kurt invented this as ‘AngLock’); have integral key and double bolt fixed jaws.

If I were putting this on a Haas or Fadal or other serious machine I would likely never have looked at Shars at all, but I figured in this case it was worth it and bought two. I can fit three (and squeeze in half a fourth if necessary), but this should be good for now.

Unboxing time. Pretty clear that they’re reusing boxes from other parts for the external shipping box. That said, the box for the vise itself (bottom right corner here) at least looks neat.

Inside, there’s two pieces of foam and a smaller box with the handle in it. I’m not actually going to use this handle, but I did notice that it’s just bouncing around in its box (banging on the side of the vice), which seems like an oversight to me. It’s clearly beaten up the box it’s in really well.

The vises also include individual data sheets, although I have my doubts about their veracity (the classic cheap tool QC ‘measurement’ that looks hand written but is printed on is definitely a warning sign here). The numbers in the upper right hands corners do at least match the serial numbers shipped to me.

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The vise itself is in a blue plastic bag with a decent but not overly thick coating of a pretty sticky oil (does not appear to be as viscous as Cosmoline or any of the other really thick oils I’ve seen on other cheap vises).

Once these were on the bed I tried out loosening and tightening them, and these things are seriously tight. No problem with my standard short ratchet wrench that I use on the mill anyway, but still concerning. Upon further inspection, it looks like there is junk in the threads. If that’s gotten into the nut portion of the moving jaw, it may be binding. Alternatively it might just be a very tight

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Overall, the fit and finish is basically what I expected. From a mechanical perspective, the fixed jaw key doesn’t look great. The key itself doesn’t look the same from one unit to the next, and I can’t tell if there’s a weird relief being cut where the key meets the jaw, or if that’s just a poorly ground surface. There are also paints flecks in a few spots that should be bare and bare metal in a few spots there should be paint. I see minimal tool marks on most of the surfaces seen from the top, I’m not sure if these have been polished post-grinding or if this is just a finer ground finish than I’m used to seeing.

The bottom has similar issues to the top in terms of paint. Not a big deal, but also not that hard to get right. The vise includes two 1/2″ x 3/4″ keys but I have 9/16″ slots so they’re not useful to me. It is nice that it has key locations along both axes. The grinding on this side is definitely visible and looks a little non-uniform, I can’t figure out if this is scratches from some other part of manufacturing and not all grinding marks.

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That’s it for unboxing, next step will be measuring these things to see if they match the specified flatness and parallelism.

Compressor Refurbishment – Part 3

Since the compressor is apart, I might as well check out the head and see what needs to be repaired in it. Since the head was off the unit, I pulled out the pistons. Dirty, but overall they don’t look worn or damage, which is nice. The big one is the low pressure piston (compresses air from outside), the small one is the high pressure piston (compresses air from the LP piston).

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Dirt on both will be removed with some disk brake cleaner (it was handy), and they should be ready to go back in. Time to check the cylinder bores. First the low pressure, then the higher pressure.

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Looks like the exhaust valve on this is pretty rusty. Maybe caused by condensation as the hot compressed air is forced out past it? You can see another of the seals here. They’re used at all the connection points, I’ll have to grab a plastic scraper to remove them.

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Not the greatest picture, but again the exhaust valve looks a little rusty. Of course, to pull the valves I had to drop the head back on the crankcase. Poor planning on my part.

Those are some pretty rusty valves…time to clean those up, order replacement gaskets, and pull the bearings on the crankshaft so it can be mounted onto the lathe.