Tuesday, September 23, 2014

Its been awhile, damn, where to start?

Bryco #59 I made a firing pin for

The last several weeks Ive busted my ass trying to get the shop and my machinery/tools to the point where I could solicit some good work. By good I mean - no production, cnc be damned, no production; small, precision parts, preferably in softer material like aluminium, brass, 12L, you get the idea; jobs where I get an entire assembly or close to it, so I can peep what theyre trying to do. Ive brought everything out that was packed and picked up a few new pieces, nothing extravagant, just things that I absolutely had to have to move forward and look for work. Every little project has inevitably branched off into 3 or 4 supporting projects, modifying tooling for a particular task or making it from scratch. Another HUGE leap forward in this whole endeavor was finally getting some decent measuring tools. Even if a pair of 8" Mitutoyo Absolute calipers and decent test indicator cost more than any other item added over the last couple months. But, man does it feel good to know you can trust what your tools are telling you. That Harbor Freight crap is completely worthless when it comes to measuring tools. I cant remember where I got the 6" dial calipers and travel and test indicators with a mag base, but all that shit is junk too. This is the third time Ive bought a pair of 8" Mitutoyo absolutes (I sold one pair when I was broke and lost another) and I know they are built to last and will check dead on for many years to come, even using hard everyday.

Basically what is to follow will be a picture dump. Though I didnt bother taking pics a lot of times, I did bother just as often. I will post again later and go in to detail on the 1 or 2 projects that 'deserve' that sort of attention. The pics and the brief descriptions will have to do until then.

A quick summary of all thats went down, is as follows -

  • Added a band saw, air compressor and drill press to the machinery list.
  • Annexed about 10' of the garage, which now holds the saw, stock rack, bench grinder, and air compressor.
  • Added coolant to the lathe and am in the process of putting tapered bearings in the spindle (this should be a GIGANTIC improvement in rigidity). I also lapped the ways and made a backboard for it that holds 4 bins for organizing and added a big led worklight which will be wired in with the machine and switch added on the panel, just like the coolant. Ive also started mounting the steppers.
  • Organized everything a little better since my space is so incredibly limited. Making it all fit and not being a total cluster is harder than it sounds and doing just a few tool box drawers has been known to eat up a couple hours.
Well, those are the high spots, lets look at some pr0n

These are the gib strips for the saddle(cant remember what they are called). See that whitish line that runs parallel to the edge? Thats where it has been adjusted improperly and was only making contact with the bottom corner of the

The prism under the saddle. Look how grubby and nasty. Thats supposed to be a precision surface. Your working surfaces cant look like that and expect good parts when the sizes or tolerances are the same size as defects lol..

Again, look how bad it looks. This is even after lapping a bit with toothpaste. The pic below is the bed entirely slathered down with toothpaste, yep toothpaste. Any mild abrasive will work, but as I found out when I followed advice found online, Mother's mag and aluminium polish is tough to beat.

60 degree triangle file with some 220 grit sand paper wrapped around it to begin the lapping process. This was followed by 500, then 1000, then 1200, then Mother's polishing compound, on all ways and dovetails. Though the compound still needs major attention, it can wait. I never use it anyway, though I did see a great idea on mini-lathe.com to make use of the compound - dude took his compound and mounted it to a 3" angle plate to give him the third axis needed to do mill work on his lathe. I will be doing this one day when I get time.

Sandpaper on the ways and carriage slid across it for several minutes.

Improvised handle to make sliding the carriage back and forth along the ways thirty billion times, easier.

Some pics after lapping

The back of the apron. This only had a piece of thin clear plastic to protect/keep clean the internals. It was full of chips when I took it apart, and I aint even had air until recently, so it wasnt me blowing chips in it. I cant believe it, but I forgot to take a pic of the new cover I made from brass. I tried to get as good a pic as I could with it back on the machine. Below is the result of that effort.

Lol, you can barely see a little piece of it.
Since Ill have stepper motors handling power feed, and hopefully threading, I have no use for the gear train any more.  It will likely stay this naked on back or even more so. The lever and tumbler gears right under the spindle bore are for feed direction, I think Im gonna use that whole area to add a back gear.  A back gear with those tapered bearings and I could take some monster cuts. Ill have to be careful since at that point it could take a cut that was beyond the limit of the other parts strength. I could seriously bust some shit.

That looks rather pimp if I say so myself! I still have a ways to go on it. I am remaking the standoffs to add at least a couple more inches to accommodate the x axis stepper and put less of a bind on the coolant line.

I made some 1.5" standoffs for the chip guard. I had it completely off with no plans of putting it back on because it was really just in the way, the way it was before,bolted directly to the bed casting. Chips would build up on that 'shelf' and the only way to get rid of them was to scoop them up and  throw em away. Now chips can make it all the way to the chip pan ,OMFG imagine that!

Coolant, glorious coolant!

Soon to be nasty coolant bucket.

A part I made to make an indicator holder from a couple of scrapped helping hands. See it being used in the pic below.

It didnt last. I ended up having to order a real mag base. Btw, that part being indicated in is one of two GT2 pulleys I ordered from rep-rap, the 3-D printer folks, to put on my steppers. I got two pulleys and 36" of belt for $17 shipped. Not bad imo.

I had to make a fitting for the coolant setup since they either dont make what I needed or I couldnt find it. This part of it is just a 1/4" hose barb cut off another fitting with the hole heavily rounded with a debur tool.

The above part was dropped in to a compression nut, which was bored out to give clearance to the hose barb and then soldered in.

Small tubing and specialty stock Ive been getting cheap lately. Something about the tiny tubing and structural type material I just like.
Soft jaws for the vise. These are something you really cant do without.

More on how I did these later. It's worthy of the attention since there is a trick to epoxying the magents in.

Enclosure for the air compressor. Without it, its the loudest most annoying sound in the universe.

Dat saw. Its horizontal or vertical. I prefer vertical.

Here's my babies! These are the smartest money spent as of late. I spent 20 years with a pair of 8" absolutes in my hand just like those. Just having them around does something for me mentally. It keeps my head in the game, so to speak.

The new bearings for the spindle. Putting them in right now. Itll take till tomorrow afternoon at least since I want to add some sort of proximity switch in the headstock before I put it back together. That way The NC software I use will have access to spindle data, the first step to getting it to cut threads or take an inch per rev feedrate.

All dem guts tore out. How she stands right now.

The outer race pressed in to the rear bore. It sure enough looks naked back there now lol.

The spindle removed and all the various gears and spacers and one of the bearings put back on it so I could stare at it. One of the spacers has to be shortened since the new bearings are 1.25mm longer. Thats .049" and I have to do it with a saw, file and sand paper. That should be fun. Not.

Wednesday, July 2, 2014

Test Tube Stirling - Quick Video Clip

Just a quick clip of the displacer piston being dropped into the cylinder to show the fit. I don't have the connecting rod attached. It still comes to a relatively soft stop with the connecting rod attached, but it's moving faster, which makes it harder to see that the landing is being softened. So, you really cant see how awesome the fit is.

Thursday, June 26, 2014

Fly Cutter

I need a fly cutter to square up the 1.812"x2.000" block for the stirling. I could buy one, but I can also make one pretty easy. Id rather it be from tool steel, and I have a piece of 4140PH that would be perfect, but with these ball bearings in the spindle there's just no way. So aluminum it is! The first challenge is getting a piece cut off the hunk of stock I have. Since I have no bandsaw, part off is my only option. I used the part off tool down to about .6" diameter then finished it off with a hacksaw.

You can see how close everything is. Had I not milled that one part down so I could flip the compound around I wouldnt have been able to get the travel out of it.
Look at the crappy fine chip. The chatter is unreal. I need to put those tapered bearings pretty soon. Why they don't already do that when they build these is the one and only serious gripe I have with this machine. 

Finally, a piece I can work with. Now let's make it look like a fly cutter. Below is a short clip of me roughing the OD down.

I decided on .75" shank. First side is done!

Picking up center with the ol' trusty edge finder.

Now we're making a bit of progress. This is one of the first 2 or 3 cuts.

Thats all we need, three 1/4-20 drilled and tapped holes where the lines are, and it's done.

This is the angle the tool will sit. I could have gotten by with a smaller angle, but this'll work just fine.

Here you can see how the end mill dug in on a few of the beginning cuts. To clean it up, I would have had to take too much off that face and it would've blown my centerline by .04" at least, likely more, to get all that out. It's not gonna hurt anything like this. I struggle with rigidity on this little thing. Between the shoring block and tightening the gibs way down it did okay, but its a bitch to turn, because everything is so tight. I do plan to do some rework or whatever it takes to squeeze a bit more rigidity out of this thing.
Ill probably make another one. I think .5" might be a bit much maximum capacity on a little two inch aluminum fly cutter. Not too much to work, it'll still work fine, but mill it for 1/8" HSS blank, which I have a few. I think it would do a much better job. This will work for now, though. I can fit any tool I have in this one, though. The tool I plan to use is a 3/8" indexable(surprise, the one in the pics), but I'm likely to throw a chunk of HSS in there too depending on how well the indexable tool cuts. I haven't been real pleased with them so far and never use them. Im hoping to redeem them by finding they work perfect for a fly cutter.

That finish isn't the greatest, but it's because of wobble in the milling attachment, it too needs some attention to make it more rigid. But its cutting great. It sounds good, no chatter, just all around doing a great job. I am going to make another, though. I've realized some things that are important that I didn't realize before, for instance, making it to use 1/8" HSS blank and also to have a 3/8" shank so it can go in my end mill holder. Those two things alone will make a huge difference for the next tool. 3/8" shank wouldn't be nearly beefy enough if you were whacking at something with a tool like what I have in there now and taking a decent depth of cut, but 1/8" HSS blank, nice and sharp, shiiit, be perfect. I didn't have set screws, so I had to use those big honkin' socket head cap screws.

Now I can square up the main block of the stirling easily. Below is a short clip of it cutting. Listen to that cut, that's just how you want it to sound.

Wednesday, June 25, 2014

Test Tube Stirling - 2 Cutting The Glass

I remade the one I cracked and I shortened the displacer by about a half inch. I'm getting pretty damn good at cutting this glass! Ill take this post to briefly explain how I cut them on the lathe with a diamond file and to show the reworked and new parts.

Masking tape is the biggest thing you can do to help yourself since until a groove is established the file wants to slide all around. The gap I leave is not much wider than the width of the edge of the file I use.

Chucked up in the lathe and ready to go, I turn at about 1200 rpm and use no lubricant/coolant.These are the two files I usually use, though I do use a flat one sometimes if the edge is jagged from chipping or breaking catiwampus, the flat file lets me bring it all flat again relatively easy. The one I cut with is a knife shaped one with a fairly fine "cutting edge" of about .03"(I put that in quotes because technically the whole file is a cutting edge since its coated all over). I use the round file to clean up the inside edge after the cut is complete. You can get a cheap set of diamond files for $10 online or at Harbor Freight. It cuts this borosilicate glass great and they're also great to have around for doing detail when shaping a HSS tool bit or just putting a nice radius on a newly ground tool tip. They're nice to have around, get some!

You never want to put any pressure on the file besides what is necessary to keep the file flat and in contact with the workpiece. If you're impatient this may be a bit of a challenge to not put any pressure at all on it, but trust me, its cutting and after a couple minutes itll just fall off nice and easy and there'll be no chips, cracks, jagged or sharp edges, just a beautiful smooth edge. I polish the edge with some 220 grit emery cloth to finish up, seems to work pretty good.

Here's some more pr0n-

This will be the power cylinder. I did put a scratch around this one on the one end. Taping it up good is necessary unless you can manage to not deviate at all from where you first put the file, and before a groove is established that's pretty much impossible.

Here's the reworked displacer. I shortened it by ~.5". On the left is the cut end of the new main cylinder, the one I cracked in the previous post. Look at that beautiful edge! 

Here they are they way they will be assembled in the end. The fit is so close that dropping the displacer, even with the heavy shaft attached, it comes to a fairly soft stop. It's not so much that friction or drag will be an issue, but just the perfect amount, .006" per side, .012" total, to be exact.

Here's a sketch that is still evolving, but it does show how I intend the main body to be laid out. The flywheel will be situated in between the shaft from the displacer and the power piston on the left. I will provide actual cad files for things soon as I need to stop using my notebook for EVERYTHING. I know how to use the software, I just need to install it and do it. But, for now, this will give you some idea of the direction Im headed with this thing.

This is gonna be a pretty fun one to get going. Stay tuned!