Having been enamored with the 5C collet chuck on the 9×20 lathe, I certainly wanted the same for the big Keiyo Seiki.  Not having a whole lot of use for the 9×20 anymore, I decided to simply move the chuck to the much bigger lathe.  I looked around online for a suitable adapter plate, but I wasn’t sure of precisely what I needed, so I went back to New England Brass & Tool and Bob had just the adapter plate I needed in stock, and at a price lower than I had figured.

This was a semi-finished backplate, which means that it still needs final machining to fit an attached chuck (more on this later).  However, it also had the recess for the spindle’s indicating lug off-center.  I’m not sure if this was actually intentional, as the lathe’s indicating lug is right on center with the rest of the bolt pattern:

Well, there were two possible solutions – either drill a new indicating lug recess on the backplate, or drill and countersink new mounting holes through the backplate and use the existing recess.  I decided to just drill a new recess, opting for simplicity, as I’m sure I wouldn’t be able to drill 3 new mounting holes with the same accuracy as the existing ones.  The indicating lug hole doesn’t have to be super precise anyhow – I think it’s simply there to make sure that the same holes on the backplate match up with the same holes on the spindle with each mounting, ensuring better accuracy.

I clamped the plate to the mill’s table with a hold-down clamp that was almost the perfect size (I filed the tail end of the clamp a little to get it to fit the inside of the plate).  I then found the center of one of the mounting holes and set its location as the origin on the DRO.

I then moved around to the other holes and the recess for the indicating lug, noting the coordinates for each one.  I then whipped up a quick CAD drawing with each of the 4 points to see how far off the lug recess from the bolt circle was (if anything).  It looked to be off of the bolt circle by only 0.002″, which I’d simply consider measurement error on my part.  I then determined the X,Y coordinates for a lug recess centered between two of the mounting holes.  Back at the mill, I shuttled the table to this location, locked the ways (on my old Tree, locking really doesn’t put a lot of clamping on the gibs, but it helps keep things steady), and proceeded to center drill the spot, then drill down about 0.4″ with a 1/2″ drill.  The recess needed to be just a little over 3/4″, but I didn’t have a 3/4″ drill, so I used a 3/4″ endmill to bore the depth.

After bringing the recess to size with a boring head, I removed it from the table, cleaned it off and tried attaching it to the spindle.  The screws went in rather tight, and it had difficultly squeezing flat against the spindle.  I guessed that my hole for the indicating lug was off by just a bit, and I was squishing the lug.

After removing the plate, I had a look at the lug recess and saw the telltale signs of metal interference:

I clamped the plate back onto the mill table and bumped the 3/4″ endmill up against the marred edge of the recess.  I then zeroed the DRO, retracted the quill, moved over about 0.005″, then milled down about 0.3″ to relieve the area that was binding.  I put the plate back on the spindle, and the screws tightened up a bit easier this time, so I considered the rear of the plate to be complete.

The front of the plate has a raised boss that slips inside the rear edge of the chuck to keep it centered, and this boss must be cut to size once the plate is mounted to the spindle.  This ensures that the boss is cut perfectly concentric with the lathe’s spindle (something impossible for the manufacturer of the plate to do, as every spindle will run just a hair different).

I had to take the diameter of the boss down about 0.060″ or so – I used a carbide bit and took pretty light passes so I could ‘sneak up’ on the final dimension without cutting any further than necessary.  Once I got close, I’d stop the lathe, clean off the chips (dust, really – the plate is cast iron, which creates more of a coarse powder, like fine sand, rather than chips like you’d get from aluminum or steel), and try fitting the chuck to the plate.  After the final thousandth of an inch, the chuck slipped on with no side play, and I fastened it in place with the mounting screws.

Now I was curious to see just how accurate the chuck was – with the backplate cut so perfectly, I should ideally see zero runout on the chuck.  I attached a dial test indicator to a magnetic base and had a look.

Before even checking the runout, I decided to see how rigid the chuck and spindle are on the lathe – on the 9×20, I could get the indicator to deflect a thou or two just by pushing firmly on the chuck perpendicular to the spindle axis.  I pushed with about the same amount of force with the same chuck mounted on the Keiyo Seiki, and watched the indicator needle anxiously.  Not.  Even. A. Single. Twitch.  This beast is solid.  A side effect of such rigidity is that a runout measurement should be a lot more accurate, so let’s see what we have…

Appears to be just under 1.5 thou – not perfect, but good enough for the moment.  On the 9×20 I had cut the boss on the backplate a bit undersize accidentally, but the extra slop actually allowed me to adjust away the runout by carefully snugging up the mounting screws, checking TIR, gently tapping the chuck in the appropriate direction with a mallet, checking again, tightening the screws further, and so on to make the chuck run true.  Of course, the collets themselves have runout as well, but I don’t worry much about that if I can get the chuck adjusted well.  But enough of that for now – time to cut some metal!

My big Keiyo Seiki lathe came with a simple lantern style toolpost, which is considered pretty ancient as far as toolholding technology goes.  While they do have their uses (the narrow profile is quite nice for certain workpieces or setups), a quick change toolpost will be much more useful to me, especially when doing small scale production.

I wanted to get something really good for toolholding on this lathe, and the Aloris wedge-type quick change toolposts we had on the lathes in class were the Cadillacs of the field. Unfortunately, they have a pricetag to match – a local machinery dealer has a used Aloris CA set but wants $700 for the kit. Much as I hate to contribute to a trade imbalance, getting a Chinese made clone would be the only way to afford such a setup. I looked around at some of the offerings, and word on some of the machining forums was that the units from Quality Machine Tools weren’t half bad (but that the set screws and other hardware they come with are poor and should be replaced).

The big decision was whether to get a CXA or CA style toolpost – the difference is size. Measuring between the top of the T-slot on the lathe’s compound and the tip of a live center in the tailstock gave me a distance of 1-15/16″. Using the dimensions found in the Shars Tool Co catalog (I assumed that it’s probably the exact same stuff as what Quality Machine Tools sells), I determined that either CXA or CA would work fine for the range of sizes that their toolholders were designed for. I decided to go for the biggie and ordered the larger CA unit, as it would allow me to use 1″ square tooling.  Plus, I remember chatting with a retired machinist many years ago, and he noted a rule of thumb when buying machine tools – if you have a choice between a machine that weighs 5 tons and one that weighs 7 tons, and both otherwise have identical specifications, always buy the heavier one. The extra mass means extra rigidity and better vibration dampening, which translates to being able to hold tighter tolerances and better finishes on machined parts. Never pass up the chance to listen to an old machinist – those guys are treasure chests of practical wisdom.

When the toolpost set arrived, I was rather taken aback at the weight – this was a beast.

The T-nut that the toolpost bolts to the compound with is oversize so that the end user can cut it to fit (there being a very wide array of T-slot sizes).  I took a few measurements and tossed the T-nut on the mill.

I still need to replace the set screws and other hardware on the toolholders, but thus far I’m quite impressed with the pieces for the price.  The dovetails fit up very closely, and honestly, I can’t imagine that the extra $500+ to get a ‘real’ Aloris would actually net me much more.  Now to scour Ebay for some beefy 1″ Kennametal insert holders…

It’s a pretty sure sign that you’re a machine tool junkie when you browse through the craigslist ads, see a machine that you have no room for, no acceptable source of AC power for, and no conceivable need for, but you still check the balance in your checking account.  Such was the case the other week when I saw a Sunnen LB hone for only $250. I have no immediate need for one, though there are a few projects in mind where it would be useful. There’s hardly any info on them available (entering ‘sunnen model lb hone’ into google yielded as the first result… …that very craigslist ad), and this one was in need of new belts at a minimum (I had stopped by to have a look at the unit, being only 5 minutes away from work). Still, after pondering it overnight, I left a voicemail for the seller the next day telling him I’d take it. I got a voicemail back informing me that it had already been sold. Phew, what a relief!

I have a number of machines currently in my possession, though in this post I’ll just talk about the lathes, as the newest one is the source of most monetary expenditures as of late.  A puny little Grizzly 7×10 lathe was my first machine tool purchase many years ago, and it was so small that it’s not even offered anymore, having been replaced by the 7×12.  For those unfamiliar with machine tool lingo, calling a lathe a “7×10” or a “12×36” is roughly analogous to calling an engine a “305 cubic inch”, as the ‘displacement’ is essentially what is being described – the first number refers to the size of the largest diameter part that the lathe can hold, and the second number refers to the longest length part that can be turned ‘between centers’, which is a common method of workholding.  In the case of the 7×10, it could work with a short stubby piece of 7″ in diameter, or a long thin piece of 10″ in length, hence the 7×10 designation.  It wasn’t a great lathe, but it had all the features I wanted, especially the ability to cut threads.  I knew I’d probably wind up getting a larger unit someday, but this one sufficed just fine as a ‘trainer’ model.

Sure enough, many years later I really needed an upgrade, as the little 7×10 just didn’t have the torque, rigidity, or capacity that I needed.  Plus, having to swap gears (plastic ones, no less) to change thread pitches was a pain.  I eventually worked out a trade with Doc Nickel, who was also on the upgrade path – I had a bunch of solenoid valves, and he had a Grizzly 9×20 that he had outgrown. It was just the thing I had been looking for, and it certainly had a bit of history behind it, having modified countless paintball guns into custom works of art. Of course, I then wanted to modify the machine after a time, and I decided to replace the 3-jaw chuck with a 5C collet chuck for improved workholding on round pieces (getting a good grip on parts with a 3-jaw chuck generally leaves unsightly dents in the part where the jaws have dug in). Not being exactly sure of what mounting system I needed for the chuck, I called New England Brass & Tool, and Bob Cumings made certain to get me just what I needed, even throwing in a depth stop as a freebie, as he knew I’d find it useful. The 5C was indeed a great addition, and in fact I never took it off.

While that was all well and good for workholding, the toolholding still needed attention – like the 7×10, the 9×20 had only a turret style toolpost. Not that a turret toolpost isn’t bad, but the stock toolposts on these little import lathes simply aren’t very good – they’re poor imitations of ‘real’ turret toolposts, and are used simply because they’re inexpensive to manufacture. I bought a Phase II piston-style quick change tool post, which, as the name implies, allows for quick changes of tools, each held securely in its own dovetailed toolholder. Additionally, I removed the compound from the lathe entirely, as they are not particularly rigid on these lathes, and I couldn’t forsee turning many tapers. Instead, I mounted the toolpost to a thick aluminum plate which itself got bolted to the cross-slide (which thankfully has T-slots perfect for this). This served me well for quite some time, but of course it couldn’t last. Once I moved up to a full size vertical mill I naturally needed a lathe to match, especially after taking a lathe class at MATC – after using a Summit 18×40 for a semester, I could barely even look at my feeble 9×20.  (Not to mention that the class lathes were outfitted with DROs, Aloris (real Aloris, mind you) wedge style quick change tool posts and a full complement of Kennametal tooling)

I first had my eye on a used Jet 14×40 at a local machine tool dealer – it needed some parts, but it had a big 3″ bore through the headstock.  The dealer wanted $3000 for it, and I figured I could save up the cash for it.  Naturally, though, someone swooped in and bought it.  I then had my eye on a nice big Andrychow TUG-40 from the same dealer – certainly a nicer, bigger lathe, but with a pricetag to match – something like $5700.  Ouch.  I figured I’d have to make acquiring a big lathe a much longer term project.  I browsed craigslist for months on end, hoping to find just the right one at a price that wouldn’t kill me.  Then, in January, I found the one I had been waiting for.

What a beauty – a 17×48 monster, even larger than the lathe I had used in class.  With a 7.5HP motor, this beast should easily be able to chew through anything I dare to feed it.  And a full quick change gearbox – no more messing with change gears or even belts for speed changes!  The price was a steal at only $2100, and I knew that I better nab it now or live a life of regret.  Of course, buying it and actually taking delivery are two very different things.  I called Big Red Movers for a quote on actually moving it home, but they tossed out a price of $1000 for the service. Yeah, like I’m going to drop half the cost of the machine on just transporting it. A bit of chatting with coworkers finally hooked me up with someone with a truck and dump trailer who was able to help me haul it over to work. It was forklifted onto the trailer at the seller, and forklifted off the trailer at work, where I could temporarily store it while figuring out a way to transport it home.

I decided on building roller bases for the lathe in order to get it home and into the garage, as these had worked very well for my vertical mill. As long as the unit could be loaded onto a rollback tow truck, it could be rolled right off the truck bed (using the truck’s winch to gently lower it down the bed) into the garage. My dad managed to dig up most of the metal needed for building the roller bases, and I welded them up at work. I used the same Fairbanks swivel casters as I had on the mill bases, hoping that they’d be able to withstand the heavier load of the lathe. Once I had the bases built, I forklifted the lathe onto them, and wonder of wonders, they held. After that, it was a simple matter of hiring a rollback tow truck, rolling the lathe onto the bed (via the loading dock at work), and then bringing it home. I asked dad if he could help me with the unloading, as it makes me feel a lot better having someone around who has far more experience in such matters. Fortunately, the lathe came down the bed extremely smoothly, and we parked it neatly in the garage with a minimum of fuss. I’d deal with unloading it from the roller bases at a later time, but for now I could simply smile with satisfaction at finally having a ‘real’ lathe.