Magic Smoke

New camera - Nikon D7000

Sat, 18 Dec 2010 21:21:00 EDT

After three years with my Pentax K10D and two lenses (18-125 and 70-300 zooms), I've been wanting to expand my lens horizons. However, I realised that choosing Pentax limited me quite a bit. After thinking it over for a month or two, I bit the bullet and switched to Nikon. For the moment I have less flexibility than I did before - I have only one lens, an 18-200 zoom. But in the long run, the wide selection of Nikon compatible lenses is a win.

I was going to get a D90, but we got an end-of-year bonus this year, and I decided to step up to the shiny new D7000. So far I'm thrilled with the results. The Pentax had a back focus problem - if I focused on a bird, it would often be blurry, but the tree 4-6 inches behind it would be sharp. The Nikon has no sign of that problem - when focus is off, it has been my fault, not the camera.

On Thursday I took the new camera to the North Chagrin Metropark, and got these photos (click for larger):

Buddy gets a little buddy

Sat, 18 Dec 2010 20:57:00 EDT

I've had Buddy for about six years, and always figured I'd be a one-dog person. But in late August, a woman who fosters dogs for the local APL brought two puppies to the dog park. One of them looked almost identical to Buddy, and I fell in love. I had to think it over for a week or so, but on September 11, 2010, I adopted Buddha.

Here is Buddha with his big "brother" Buddy, the day I brought him home.

The resemblance is really amazing, considering that they are both mixed breeds. (Buddha wouldn't sit still for this photo.)

More first day home photos:

About a month later:

And now, about three months later and 6-1/2 months old:

Dog photos

Sat, 03 Jan 2009 20:27:00 EDT

I haven't posted any photos from the Metropark lately, because I've been taking the dog instead of the camera. Today I decided to see if I could manage both at the same time.

The last photo is a bit blurry, but I like how it somewhat captures his enthusiasm - it was snapped a split-second after I released him from sitting with a "come!".

Sailing and Birdwatching

Sun, 21 Sep 2008 11:52:00 EDT

Never pass up an opportunity to go sailing....

The heron was on the side of the river that runs from the dock area to Lake Erie, the other pics were out on the lake itself.

Spindle Project - Part 2 - Deciding on a Taper

Mon, 08 Sep 2008 01:09:00 EDT

The "Spindle Project" is my attempt to make something useful (and perhaps somewhat profitable) out of some surplus machine tool spindles that I bought in late 2007. This posting is about choosing a spindle taper and toolholder for the spindles. (See this posting for background on the spindles themselves.)

TTS Tooling

My existing milling machine is a Shoptask 3-in-1 that I have converted to CNC using EMC2 as the control software. It has a #3 Morse Taper on the mill spindle. I use " Tormach Tooling System" (aka TTS) toolholders on the machine, with a 3/4" MT3 collet in the spindle. The TTS system is a nice arrangement for small to medium mills - it is quite rigid for its size, and very repeatable in the Z direction. The toolholders have a flange which engages the spindle nose as the collet draws them in. Below is a drawing of a typical TTS holder, and a photo of my selection of TTS tooling. (Click drawings for a scalable PDF file, click photos for higher resolution.)

Since I already have some TTS tooling and plan to get more, it is naturally a leading candidate for these spindles.

Before I focus entirely on TTS tooling, I wanted to examine any other possiblities. The first thing to come to mind was of course R8. You can get R8 tooling anywhere, at very competitive prices. The main problem with R8 on these spindles is the length. As the drawing below shows, the back of the collet goes way up into the spindle.

The back of the collet would extend so far into the spindle that the step where the drawbar springs sit would be removed. That means I couldn't use the springs - I'd have to use a regular drawbar.

I would also have to figure out how to enlarge a 0.236" (6mm) hole that is over 2-1/2" inside the spindle, and make a precision 0.950" bore 4" into the spindle. The spindles are hardened (at least case-hardened), so the machining wouldn't be fun. I have a carbide boring bar with cermet inserts that can cut hardened steel, but it is far too large to get into the 6mm hole. I have no idea if an ordinary drill would touch it, and I don't want to think about what a carbide drill might cost.

And finally, the 1.25" diameter at the gage line leaves very little of the "step" on the front of the spindle. I would have to remove the step and machine the front of the spindle flat. That would move the taper another 0.160" deeper into the spindle, making all the other problems even worse. So, R8 is out.

NMTB-30

NMTP-30 taper tooling is roughly the same diameter as R8, but considerably shorter. Tooling is less common and more expensive, but not outrageously so. So I dug out Machinery's Handbook and drew up a 30 taper toolholder. The result is below.

Although I would be able to use the drawbar springs, and wouldn't have to do a precision bore 4" into the spindle, the 30 taper has all of the other problems that make R8 impossible. And it costs more. So NMTB 30 is out.

TTS with a MT3 collet

The Tormach Tooling System toolholders only extend 1-3/8" into the spindle - that seems perfect since I really don't want to try machining deep inside the spindle. The standard way of holding TTS tooling is by either an R8 collet or a #3 Morse Taper collet. Tormach sells both collets and they aren't very expensive. I already know that R8 is too long, so I measured up the MT3 collet from my Shoptask, and added it to the drawing.

The MT3 is better than R8 in several ways. It is short enough that I could use the drawbar springs. It doesn't remove so much metal from the nose, so I can keep the 0.160 step on the front of the spindle. I would need to make a 0.160" or slightly thicker "washer" that would mount to the spindle nose, and be turned or ground square for the toolholders to seat against. That won't be too hard - there are already four M3 threaded holes in the spindle nose that would work perfectly. The washer would also cover up some other holes in the spindle face to make it a bit smoother and neater.

Unfortunately, the MT3 collet is still too long - I would have to clear out the 6mm area of the spindle. It wouldn't be a critical dimension, since the collet only bears against the taper for the outer 1-1/2" or so, but it would still be difficult to do.

Also, if you look closely at the drawing, you can see that the Morse Taper surface intersects the original taper near the end of the spindle. The existing taper is mirror smooth and very hard. If the spindle is case hardened, my new taper will transition from very hard to less hard material. That will make it hard to get a good fit and finish.

The conclusion is that I could probably use the stock MT3 collet, but it will require some very tricky machining.

TTS with a custom collet

Since the main problem with the MT3 collet is its length, I started considering a shorter collet. TTS shanks are short enough that it should be possible to remove 3/4" or so from the back of the collet and still have enough flex for it to close properly. However, simply cutting down the existing collet won't work - the threads don't go deep enough. I started desgning a collet that I could make from a hardened and ground MT3 to MT2 reducing sleeve.

However, tonight I realized that if I'm making a custom collet, I might as well go all the way. A Morse taper is about 0.6 inches per foot. The existing HSK taper in the front of the spindle is 1.2 inches per foot. If I make a collet to fit that taper, it will probably be easier to release from the spindle. In addition, I won't need to do as much critical machining. I still need a nicely fitted straight area in the back of the collet, but I won't need to deal with the taper, and I won't have to worry about the transition between hard case and softer core. The drawings below show the collet, and how it fits into the spindle.

I have a small electric oven that gets hot enough to harden drill rod, and is big enough to hold this collet. I'm leaning towards this approach, in part because making a precision collet would be an interesting challenge.

Decisions, Decisions

I haven't decided for sure whether to do a collet as shown above, a shorter MT3 collet, or the full length MT3 collet. I just ordered a MT3/MT2 reducing sleeve, as well as a chunk of 1" drill rod. We'll see what works out best.

I haven't just been drawing and thinking. Over the last weeks I've built some tooling needed to machine the spindles, and have done some experimental turning and boring. Those results will be the subject of my next posting.

Spindle Project - Part 1 - The Spindles

Mon, 01 Sep 2008 00:45:00 EDT

The "Spindle Project" is my attempt to make something usefull (and perhaps somewhat profitable) out of some surplus machine tool spindles that I bought in late 2007. In the process I hope explore some areas of machining that I haven't done before, including hard turning, grinding, and extreme precision work.

I have sixteen spindles, all more-or-less identical (details later). I initially bought two, just for the bearings. When I figured out what they were I went back and bought the rest. A picture is worth a thousand words, so here are side and end views of an assembled spindle (click to enlarge):

After examining the business end for a while, and doing a lot of googling, I figured out that the spindle taper is HSK32. HSK tapers are relatively new and at least for the home-shop world, very exotic. Toolholders start at $200 and go up - way up. The premise behind HSK tooling is that it doesn't just make contact on the taper. It is designed to contact on both the taper and the flange at the same time, for increased repeatability and rigidity. The HSK design is also suitable for very high speeds.

The somewhat exotic and high-speed nature of HSK was my main clue that these were probaby some very high-class spindles, with correspondingly high-class bearings. Although most of the spindles had tags on them indicating that they needed repair, none were tagged for bearing problems. Most were things like damaged retention mechanisms, drawbar sticking, etc. So I decided to take a chance, and bought the whole batch.

The first step after I got them home was to remove the retention mechanism. That consists of a tapered piece that is screwed onto the drawbar, six fingers that expand inside the toolholder, and a crown-shaped piece that sits in the back of the taper and hold the backs of the fingers. Several spindles were missing one or more of these pieces, and some had broken or bent fingers, etc. The tapered center part unscrews, and the fingers and "crown" come out with a pair of needlenose pliers, leaving this:

Some more carefull fiddling around and I figured out how to get the rest of the spindle apart. Since HSK spindles are pretty much always used with automatic toolchangers, the drawbar is spring loaded. Some have a long stack of Bellville spring washers, others have helical springs that are sort of like a stack of Bellvilles where each layer is twisted and connects to the next. The helical versionis a lot nicer to handle - two spring sections instead of 132 individual washers stacked in a precise series-parallel pattern. I had to make a simple tool to allow me to compress the drawbar and retain it in that position while I loosened a setscrew and removed a cross pin - then I could release the spring pressure and the drawbar came out the back. The two photos below show the results of the second stage of disassembly:

In the first photo, the retention "stuff" is assembled as it goes into the spindle - in the second, the fingers, crown, and tapered part are separated. The drawbar in the photo has the helical springs (of my 16 spindles, 10 have helical springs, and 6 have Bellville washers).

Across the bottom row in the first photo are parts related to a spring loaded key, which engages a slot in the back of the toolholder. In the front view photos above, you can see the key on the bottom inside of the taper, and the end of the pin that holds and drive it is visible on the spindle face. The long skinny rod runs thru an off-center hole in the spindle, and is spring loaded by the largish assembly at the back end of the spindle.

I'm about 99% sure I'm not going to be using the retention stuff or the keys, so those pieces are bagged and tucked away. The drawbars, drawbar springs and various other bits and pieces will probably be reused, so they've been carefully cleaned, sorted, and stored.

The only thing left is to remove the bearings themselves from the spindle. So far I've only done that to two spindles. I figure if I don't mess with them, I won't mess them up. I might be able to do whatever work I need without removing them. If not, I'll remove them when it becomes neccessary, not before. The picture below shows one of the two that I did carefully take apart:

From the left, the pieces are: front ring (part of a non-contact labyrinth seal), front bearings, outer race support ring, inner race spacer (long tube), back bearings, and inner race nut. The bearings are two pairs of matched 25 degree angular contact ball bearings, each pair arrainged in "back-to-back" configuration. The clamping nut loads up the entire stack, with the clamp force going through the first back inner race, both back outer races, second back inner, the long spacer tube, first front inner, both front outers, second front inner, and into a shoulder on the spindle shaft.

The Bearings

The two spindles I've taken apart so far have bearings from two different makers, but they are basically the same thing. The front pair are trade size 7008, 40mm ID, 68mm OD, and 15mm thick. One vendor's datasheet for the front bearings is here. The back bearings are size 71908, 40mm ID, 62mm OD, and 12mm thick. Vendor data is here. A general page for that vendor's spindle bearings is here, and from there I was able to download their 11-megabyte spindle bearing catalog with lots of good engineering info about the care and feeding of high-end bearings. The other vendor doesn't have the same detailed data, but a magic decoder ring for their part numbers is here - the number on the front bearings is VEX40/NS 7CE3 DD/3. Both sets of bearings have ceramic balls in steel races, and are ABEC-7 grade, or the European equivalent. While googling for data on these bearings, I found a 2006 price sheet that listed the back bearings at 276 Euros each. At today's conversion rates, that is about $400 per bearing!

After much measuring and investigating, I made a to-scale EasyCad drawing that shows all the important spindle parts, along with several partial sections to show all the various holes and details near the front of the spindle. Click on the thumbnail image below to get a scalable PDF version.

The drawing does not show the retention pieces, or the key. Section B-B does show the slot that the key fits into, and the long hole for the spring loaded push-rod. The holes in section A-A are for coolant - apparently HSK tooling can accept high pressure coolant either through the center of the drawbar, or through the toolholder flange.

In my next posting, I'll describe my plans for these spindles.

Critters at the MetroPark

Sat, 02 Aug 2008 23:37:00 EDT

I took a break from my grinder reconditioning project and went to the North Chagrin MetroPark this evening. I spotted some thistles blooming along the path to the pond:

In the sunny area next to the pond, milkweed pods are getting ripe - soon they'll break open and the seeds will float away.

The pond itself is just about covered with lily pads, and their flowers are starting to bloom.

There is a "resident" blue heron who usually hangs out on the side of the pond that is least accessible from land. It is far enough from the walkway across the pond that you can't realy get a good look at him. When I arrived he was in his usual spot, but just as it was starting to get dark, he went flying across the pond. I shot several pics as he went by, but light, focus, and all the other factors were against me. The best one is this blurry shot of him skimming over the lilypads.

Once he got to the other side of the pond he started hunting. That area is much more accessible, and I slowly and quietly got as close as I could, before shooting these photos.

He caught something at least three times while I watched, including what I think is a frog in the following picture. The photo is blurry because he was tossing his head back to swallow it. By this time it was quite dim, and my shutter speed was down to about 1/8 second. The only reason the three pics above aren't blurry is because a hunting heron stands very still.

As the heron walked through the water I moved to a better vantage point. That's when I noticed another pond resident I've never seen there before. A beaver was a few feet in front of the heron, munching on lilypads.

Scraping Grinder Cross-slide

Sat, 26 Jul 2008 23:03:00 EDT

Last Saturday I confidently wrote "Tomorrow I'll bring in the rest of the pieces, clean everything, and put it back together". I should have known better.

The table ways are ball-bearing, and seem to be in good shape. Not so the cross-slide ways. They are dovetails, and have significant wear on the flat surfaces. Last Sunday I started scraping them flat. A business trip in mid-week cut into my time, but I finished today. It took 37 rounds of scraping. They are still far from perfect - I am not an experienced scraper hand - but they are much better than they were.

I took pictures before I started, and after every 5 rounds. I used GIMP to color enhance the photos, turning almost everything except the blue spotting dye to grey-scale. The image below is what I got when I first spotted the cross-slide on my surface plate. It made contact only on the front left corner, and on the two back corners. Sorry about the bad lighting, you have to look closely to see the nearly square patch in the back right. (Click on images to enlarge.)

The next six photos are after 5, 10, 15, 20, 25, and 30 rounds of scraping. In round 5, the initial patches grew a bit, but it wasn't until round 10 that I got contact on all four corners. From then on to round 30 I was mostly trying to bring the badly worn left center portion of the left way into contact. The last 1/4" or so is simply too badly worn, and I decided not to try to work the entire rest of the surface down to the level of the worn spot. Somewhere between rounds 20 and 30 I started to develop a low area on the near end of the right way. The last 7 rounds were mostly focused on fixing that, as well as improving the overall surface and breaking up any large areas.

After round 30, I stopped replenishing the spotting compound on the surface plate. That means the film on the plate got thinner after each round, and the readings became more sensitive. Large uniform areas in round 30 became collections of smaller spots in subsequent rounds, and I made smaller and smaller scrapes.

The round 37 photo below was taken with the slide rotated 90 degrees for more uniform lighting. The lighting was still a bit uneven - the photo shows much more blue on the right way, but in reality they are better balanced. There is still some uneveness on both ways, but when I go back and look at the starting photo, I don't feel too bad about saying "that is good enough". Especially since I still have to do the mating ways. I'm hoping they will be easier and faster.

One of the guys on IRC was wondering what a scraper looks like, so here is a photo of my scraper (given to me by my machinist father). It is carbide tipped, which saves a lot of honing. Behind it is my 12x18 surface plate.

Surface grinder into the basement

Sat, 19 Jul 2008 23:21:00 EDT

One unfortunate fact about where I live is that my shop isn't limited by what machinery I can afford - it is limited by what machinery I can find room for. My garage is detached and unheated, and in Cleveland's climate, that means I have to fight rust, especially in the spring. My Van Norman #12 mill is out there, but I'm not willing to put any other machines in the garage. So any new tools not only have to be small enough to fit in my rather cramped basement, but they also have to be light enough to move down the steps.

Today was the "Saturday Sidewalk Sale" at HGR Surplus (they're only open one Saturday a month). After spending a few minutes looking at a reasonably affordable and very nice Mitsui surface grinder, sanity kicked in and I walked away - it probably weighed over a ton. But a little later I found a nice benchtop 6x12 grinder. "Targa" brand, made in Tiawan (a bit better than made in China), it seems to be identical to this Enco one - 3/4HP, single phase 120V motor, 451 lbs. But it was a LOT cheaper at HGR - I paid about one-tenth the Enco price.

HGR's forklift easily loaded it into my truck, but the hard work started when I got home. Before I even unloaded it I started taking it apart to reduce weight. The table lifts right off - 65 pounds. The "saddle" (dunno what the proper term is) slid off after I unscrewed it all the way to the front and loosened the gibs - 74 lbs. Four socket head capscrews and some disconnected wires let me remove the motor/spindle assembly - 48 pounds. And finally, screwing the vertical slide all the way up and loosening the gib allowed it to be removed - 33 lbs. The remaining base casting is about 225 lbs - still too much to move by brute force.

Step 1 was sliding it from the truck tailgate onto a rolling cart. That wasn't too hard - the cart is only a few inches higher than the tailgate, and the machine was on a small pallet.

Step 2 was getting it onto the back porch. The cart is about level with the porch, so I moved it to the foot of the porch steps and spanned the gap between cart and top porch step with a seven foot piece of 2x8. I carefully slid the machine along the 2x8 until it was setting safely on the porch.

Step 3 was getting it into the kitchen. I left it on the 2x8 - it made a handy lever. By pushing the casting to one end of the board, I could lift the other end, and stick a moving dolly under the middle. Then I slid the casting back to the middle over the dolly. The 2x8 very nicely bridged the threshold of the sliding glass door, and a bit of sliding and levering was all it took to get the casting in the house with the dolly once again under it. (See first picture below.)

Step 4 is the biggie - getting it down the steps. There is a bathroom directly across from the top of the steps, and I braced a piece of 2x6 across the inside of the bathroom doorway. That served as an anchor for a block-and-tackle that allowed me to ease the casting down the steps, still sitting on the long 2x8. The rigging allowed me to have total control of the casting during what would otherwise have been some very hairy moments. The second picture below shows it just about to go "over the edge", as the 2x8 tilts from level on the floor, to sliding on the steps. The third photo shows it about half way down - note the superviser at the top of the stairs, making sure I'm doing it right.

Step 5 was getting it from the basement floor up onto the bench. I used a few deck screws to fasten a short piece of 2x8 across three joists. Then I wedged uprights on both ends, so the screws and joists wouldn't need to carry the weight. Rigged the block and tackle again, this time to lift the casting straight up. The next-to-last photo below shows it half-way up, and the last photo shows it sitting on the bench.

Tomorrow I'll bring in the rest of the pieces, clean everything, and put it back together. It still needs a magnetic chuck, but Small Tools Inc. has some used ones in the $100-125 price range that look promising.

Getting Organized

Sat, 31 May 2008 23:24:00 EDT

I've spent much of the last month remodeling one corner of the basement. It's funny how projects happen...

Back in March I ran across a great deal on a stereo microscope at HGR Surplus. I've wanted one for quite a while, so I bought it. When I brought it home and took it downstairs, I realize that I didn't really have a place for doing precision work like electronic soldering and surface plate work. My surface plate has been living on the floor for several years now, and I either use it there, or temporarily clear off a spot for it somewhere. So I decided I need a new workbench...

I went back to HGR, and found some 95" x 30" blue formica workbenches with sturdy steel frames for $35 each. At that price, I figured I might as well get two. I figured out where I wanted to put the first bench, but I knew I would want storage space above the it. That meant yet another project - framing and wallboarding the wall, so I wouldn't have to anchor stuff directly to the concrete blocks.

After the wall was done, I painted the wall and the floor while there was nothing to get in the way. Then did a little welding on the workbench frame - I decided that the front crossmember at the bottom would interfere with legroom, so I ground off the welds and moved it back about 8", then welded it back on. That was my first real welding project.

Once the bench was inside it was time for storage above it. I spent at least two weeks building the shelves in the photo below.

I finished the shelves and got the area cleaned up last weekend, and since then I've been slowly moving items over there. Today I used some of the scrap wood from the shelves to make a box for my ER20 collets.

And that is how "buying a microscope" turns into about six or seven projects that take a couple of months...