Making a Gear Cutter Arbor

I had some gear cutters for cutting some 16DP gears.  It was another break I needed away from placing a lot of stupid gears on a piece of paper to get them laid out.  I did not have a way to use them.  So, here is my stab at cutting an arbor down to size, drilling, and tapping the hole.

Now, I can potentially grab a slab of aluminum round large enough for the gear, true it up, then throw it on my rotary table and make custom gears (127 teeth and 100 tooth gears will be needed for a perfect metric thread base).

Truing a Chuck Back Plate

While preparing to create a tap in my last post, and still needing a break from that Cocoa Table project, I needed to put on a new, small chuck.  My two chucks I already had were either a 4-jaw chuck (takes a long time to get the work close), and a 3-jaw chuck that only had outside jaws.  I had ordered a small 3-jaw/4" chuck, and it had arrived.  So, it was time to get it mounted up.

1. Install the back plate to the lathe, NOT to the chuck.
2. Once it's on the lathe, use some tooling to face it off, and cut the shoulder you need for the chuck to fit.
3. Now you can remove the back plate from the lathe and install the chuck to it.
4. Once done, it is ready to use.

Yes, it is really that simple.  It was a quick task when I had just a little time to spend on it.

Creating a TAP

Hello, I needed to take a break from laying out so many little tiny gears on my dads Cocoa Table Project, and I did need to redo one of my brass pens.  In order to do that, I had to create a tap to cut some internal threads (15/64" 18 threads per inch).  I had a chunk of 1/2" tool steel from building a tramming tool in Calibrating a Drill Press, so I decided to use that.  It was a matter of chucking it up, turn down a section of that to 0.24" (15/64 is 0.235", but I wanted some space after the threads were cut).  Then, throw on the gears for threading, and cut some 18-TPI threads.

At that point, all you have is a screw or bolt.  For a tap to work, you need to cut some relief to allow the material somewhere to go.  I used a Dremel with a cutoff wheel to put in a leading cutting edge, then some stones to put some good relief in there.  I also cut two sides parallel so I could use a wrench to get a grip on it, then heated it up and gave it a good dunking to get it hard.  Worked great!

Calibrating a Drill Press

Remember that second-hand drill press I found that was made in Taiwan?  It was a little rough around the edges.  I had even checked the quill and replaced the bearings and chuck (that little South Bend chuck was worth every penny).  Well, as I've been trying to set up the tooling for building that table for my dad, I knew I needed to make sure the drill press table was level.  If it is not, you never get 90-degree holes.

In order to get it level, you have to "tram" it.  "Tram" is short for "trammel", which is a tool used to calibrate machinery.  A good trammel will give you measurements within 0.0005" - but I don't have that kind of dial indicator, nor will I unless it is a donation.  But, I needed a trammel.

I had seen a video on youtube (by Dale from Metal Tips and Tricks) on making one.  His was gorgeous, but I just needed it to work.  I ordered 1"x1" aluminum stock about 12" long, and a 1/2" chunk of drill rod, and two cheap dial indicators from Harbor Freight.  Do they have to be right on?  No, because it's a relational measurement that you are after anyway.

Once all of the parts arrived, it took me an evening of work to get the block drilled, cut, tapped, and the drill rod cut and faced, then the whole thing assembled (and to learn how to merge videos, convert them upload them and post).  Not a bad job.  Here's my new trial run at doing this - a video on youtube.

The above video was taken using a cheap Chinese "GoPro" knockoff, an SJ7000.  The camera does have its limitations (it won't do high-speed video work), but it is perfect for throwing a $40 camera into the shop and recording 1080 video (not fake 1080p resolution, the real 1920x1080x30FPS) without fear of destroying it or soaking it in cutting fluid or oil.  It's not bad, but I made the video even worse by having light behind everything - it washed it all out, but the video still came out okay (definitely not professional quality because of the way I did things).  Here's the final "product" :

With that, I threw it into the drill press and measured the table.

Forward-aft is pretty accurate (actually 0.005" off - which is phenomenal for a drill press).  Side-to-side was not so good.  It was 0.200" high on the right, and 0.200" low on the left.  That was actually amazing in itself, as all I have to do is loosen the bolt that allows it to tilt, twist the table, and re-tighten.  I'll do that on Saturday, and I should be able to drill some pretty accurate holes!

Pickle Jar

I had a proof-of-concept at one point for bleeding brakes on the car.  It was a simple design, based on a large bulk jar of pickles.  I had drilled two holes in the lid, and used teflon tape and brass fittings to seal the jar.  Then, one of the lines is run to the brake zerk fitting on the brake calipers.  The other line was connected to a vacuum source.  This allowed me to connect it, start the vacuum, open the zerk, and then simply top off the fluid at the master cylinder until I had fluid in the jar.  Functioned pretty good, until I loaned it to someone who broke the jar.  He got me a new jar, but I thought I'd make a better lid for it.

I ordered two things - a chunk of 4.25" aluminum round cut-off, and a rotary table (needed to cut the bayonets in the lid so it would lock down).  I turned it oversized according to the dimensions from the existing lid, drilled a through hole it (so I could thread in a rod and hold it up (hang it).

I then marked a groove (for concentric attachments, drilled 120-degree-apart holes, then tapped them with a pipe thread.  That allowed me to simply thread in the brass pipe inserts.

The hardest part was putting the bayonets on the bottom lip.  There were six of them, so I HAD to have a rotary indexing table.

First, I used a boring bar to cut it to a solid lip on that bottom inside edge.  Next, I had to mill out between the bayonets.  This is what required the rotary table.  I threw a collet into the spindle with an end-mill, positioned it for a cut, then simply milled the lip off to get a bayonet.

Then I assembled it into a functional brake bleeder :

While I was at it, I had a neighbor who needed a thumb screw for a photography gimble.  So, I cut two of them :

Now I can get back to work on the corvette!

South Bend Junior - How To Set Up For Screw Cutting

I have a problem.  My lathe came without quite a few parts.  I've purchased change gears, and those change gears came with a thick idler gear :

(It's the one on the left.)  You can see the gear used to transfer to the lead screw on the upper right.  Obviously, the one on the left won't fit to the small teeth on the gear on the right, so I ordered an 80-tooth one from eBay.  It arrived, and it, too, wouldn't fit :

I don't have one of those forking banjos, either :

I was not sure how I was supposed to set these up, so I looked up the gearing for cutting an 18-pitch thread :

I needed a 32-tooth gear on the stud and a 72-tooth gear on the lead screw.  I reversed the screw gear and bushing so it would line up with the large gear on the idler (the same one connecting to the stud gear).  This turned it from a compound gearing to an idler gear.

Next, I chucked up a small chunk of cheap aluminum, because scoring from a tool cutter would show up easily, and it was soft enough I could rotate the chuck by hand.  Then, I turned it a few times to get enough for a thread pitch gauge :

And measured it :

18 on the pitch!  Success!  Next, cut some actual threads.  Again, I started with aluminum.

Next, I threw on my 25/64 bar I needed for a custom tap (yes, I had to learn all of this for a tap, which was for a stupid brass pen).

I removed it from the chuck and used a dremel to cut some relief in it (some of the reliefs I cut backwards, so beware if you make a tap), heated it up red-hot, and quenched it.  I didn't care how hard it really was, because it had a single purpose - to cut some threads in a plastic insert to finish a brass pen :

For anyone who doesn't know about South Bend Juniors, that's how screw cutting is set up!

A Beautiful Spring Day in the Shop

Today, I finally had some time to spend out in the shop.  So, I tackled a few projects.  I have a neighbor who is a machinist, and a few days ago, he caught me and asked if I'd be interested in any of his cut-offs.  So, I ran over today to go pick them up :

In that pile of great stuff was some 303 and 304 stainless, brass, bronze, aluminum, steel, and even some Delrin.  I had a colleague asking if I'd be able to machine him some shock pistons for his RC cars.  They are supposedly 12mm across, with a 1.6mm hole in the middle.  I measured it up and threw down a quick drawing :

So, that 12mm is actually 11.80mm, or 0.465".  That hole in the middle which should be 1.6mm is actually 2.54mm, or 0.10".  It means I have some really good leeway when it comes to machining them.  I chucked up some Delrin, and cut five pistons (because one was a little too think).  They didn't turn out too badly!

Next up, I dropped the starter.  I needed to know how large of a fly wheel I have on the Corvette.  I couldn't find the receipt, so I had to do it.  But, I was having problems turning the crankshaft and also counting teeth while I was at it.  I remembered I had an old Harbor Freight composite camera system, so I grabbed the camera, build a frame to hold it, and placed it pointing at the hole through the scatter shield where the starter connects to the fly wheel.  That allowed me to count teeth :

I have a 168-tooth flywheel. I ordered a 2.5HP adjustable starter from eBay, so when it comes, I'll get it installed and running.  Then, I thought I'd finish a brass pen while I was at it.  It came out not too badly :

It was a good day today!