BSW

I was having some issues with threads in one of my prototypes. I was using what I had on-hand, and was putting a 6-32 thread on a stainless rod into a hole tapped into 6061 aluminum. Predictably - it did not work very well as stainless is actually very abrasive. So I consulted a long-time friend - AC1L. Richard has forgotten more about machining, radio and nozzle design than I will ever know. He holds more than a few patents and has been encouraging me all along.

He took one look at my project and said "You should try British Standard Whitworth threads."

I have run into these beasties in my 1968 MGB-GT - and they are usually more of an annoyance than a help ! However - they have several nice properties. They have rounded rather than sharp angles and for the size I need, they allow me to use a 1/8" rod without compromising thread engagement (6-32 done properly would require .164" rod) - it also has 40 threads-per-inch - so I think this will allow me to use easy to machine brass instead of stainless. This is a picture of the BSW taps, die, and the test block I made.

Touch Probe

It has been a busy few weeks despite the lack of posts. I made major headway with the Smith & Wesson M&P tool. Unfortunately I am going to keep the photos off the net for a while so it does not interfere with any potential patent decisions. It is going to be a very interesting tool...

Curiosity got the better of me and I finally ordered the Wildhorse Touch Probe. This probe sells for $140 - far less than the $1150 probe sold by Tormach. I have been playing with it and am still on the fence. I think it will be very useful for certain operations - like finding the center of a hole. It requires a bit of fiddling to get it centered - you can see the centering setup using the Starrett 650 back-plunger indicator. I do not think it will be better than the trusty Starrett edge finder for locating edges and setting the machine DRO. I played with the digitizing functions a little - it uses a "bed o nails" approach and drives straight down on the object. This will work for metal, but it will make marks on anything wooden.

Broaching Experiment

This is a double-ended tool to see how well a plain broached end works.

It works great with the long insert bits. The magnets are incredibly strong in this one so the bits are held very well. I added some engraving and checkering to the logo file. I think this will be a nice tool to have on the bench.

Rotary Broaching !

Since I started building these tools I have wanted to play with a rotary broach. This is the best way to make "hexagonal holes". Traditionally you use a "push broach" - this is slow and, requires a LOT of force to basically push the hexagonal hole into the metal. The rotary broach works by "spinning" the hexagonal shape with a 1 degree "wobble" and then you push the wobbling bit into the metal causing the cutting action around the edges - it is VERY COOL. The current production of the SPDTool uses a Rotary Broach and these tools cost BIG bucks ($800 and up). Much to my amazement, Little Machine Shop started selling one for $99 ! I couldn't order it fast enough and it actually works ! This is going to open up a lot of options for my prototyping !

Back at It...

I spent last week working on a new tool, but decided to scrap it because it was looking too much like it was designed by committee. All was not lost because I made a lot of progress on machine setup to make future jobs easier. The contactor arrived on Friday and I installed it today, but the gorilla tape was still holding it together quite well.

I wanted to try some more engraving and got 25 aluminum tags to play with. I milled out the pattern in a chunk of aluminum and drilled and tapped a 6-32 hole so I can hold them down in a consistent position (middle of tag is 1" from XY=0). I may add some screws around the edges eventually, but these aluminum ones are not made to the best tolerance anyway, brass or stainless will probably be fine with just the one screw.
I wanted to try fitting text to a curve and added a little crosshatch for texture... I can easily get brass or stainless so if anyone needs any of these let me know !

V-Carve Experiments

I've been wanting to play with the V-Carve capabilities of the BobArt software. This was made with a 1/8" endmill to clear and a plain old 3/8" 90 degree chamfer cutter. It is cut to .125" depth. The program did a nice job making a 3-D effect on the lettering. The sign is for the "Epiphany Rock" - a 700lb piece of white quartz that was being discarded after the previous owners' disturbing attempt to break it with a 12lb sledge were thwarted. It had a sign saying "U-Haul" that Val spotted so I retrieved it with the tractor and we put it where I can see it from the shop window. It is a nice place to sit and think about machining problems...

Slow Progress

I have been doing a lot of CAD/CAM work on the next tool, so not a lot to show...
I cut and finished blocks to length, and started working out the cutting and decided to start doing some more extensive software setup. The goal being to be able to pick a drill size in BobCAD, and have it generate the correct speed (rpm) and feedrate (inches per minute or inches per revolution) to get a nice clean, smooth hole. This is easy to do with a regular drill or drill press where you can "feel" the cut and watch the chips, but it is much more sophisticated to be able to click on "START CYCLE" and have the machine run the whole drill cycle.

The tables in books are only an estimate, you have to try it and see how it works under YOUR conditions and adjust the software accordingly. While I was working on that, the spindle decided not to start. When I opened the door to the inside of the machine I found the main electrical contactor (big relay) for the spindle had come apart (worse than in the picture) ! It was easy enough to snap it back together and get it working, but this is not a good component to come apart.

I Emailed the manufacturer Tormach and the tech reported that contactors should not "spontaneously dis-member" and got one out to me right away under warranty - less than an hour from my first Email. They have been an excellent company to deal with and I am glad I bought their product.

Different kind of cutting Today

We finally had a "cool breeze" day in the low 80's so I worked on more of the thunderstorm damage cleanup. This is two oaks - there are 4 or 5 more to go.

Tooling used today was Husqvarna 357XP with 20" bar. It runs at 14,000rpm, outputs 4.4hp and weighs 12 pounds.

Quick Proof for a friend

The President of Arsenal Consulting is considering throwing some work my way. He sent me his logo and here is what I whipped up. Arsenal is the "Go To" firm for forensic computer work in the Boston area.

Finished Prototypes

I finished up the machining on Friday, then the impending thunderstorms passed through and I shut down.
The assembly went OK, but I need to mill the magnet holes a little larger so they are easier to press in.

These are small cleaning kits. They measure 2.6"long, are 1" wide and .625 (5/8") thick.
They contain a pull-cord style cleaning assembly that can attach to a standard brush - the block will hold a .45 cal brush.
There is a removable brass scraper and an ampule to hold a teeny bit of oil - enough for a light lube and wipedown. The threaded brush holder and the ampule are parts that are used in the Samson Field Survivor tool.
If you coil the wire carefully you can stuff a patch into the other half of the block.
I have used it and it works pretty well. Who knows if there is a market for it.
There are a few more changes I still want to make to this design.

Software Crash !!!

I was trying to work on some tool paths and my CAD/CAM software (BobCAD) crashed and managed to mangle the license file...
Fortunately I already had created the G-code programs and it didn't slow me down much. I placed a support call and got it resolved later in the afternoon.

The only casualty for today was a 3/16" x 1" long carbide endmill. I got a LOT of pretty deep cuts done with it and it was starting to get dull, so its time had come.
Here are some pictures of the process. The first one is setting the Z. This handy tool is stupid-simple. When the bit touches the spring-loaded top, the light goes on (duh). It is exactly 2" tall so you just set the DRO (Digital Readout) for Z to be 2". It is a lot easier and faster for me to do it this way than trying to see exactly when the bit touches the part and setting to 0. You can connect a wire to it and use it for the same purpose on non-conductive materials (plastic, wax, wood...). They cost about $100 but are well worth it. It uses a 1.5v flashlight bulb and a standard 357 watch battery. The other picture are the blocks I worked on today. The plan is to add a few more holes, engrave logos and assemble them tomorrow. I'm not saying what they are just yet...

Some deep hole drilling...

Still playing with blocks...

A 3D-engraving Project

This is a project I did for my cousin a few weeks ago...

Here is some video of the machine cutting it. I think it took over an hour to run the whole job...

Welcome to SPDTool Time !

I am going to start putting up pictures and videos from the SPDTool shop. Some of these projects are prototypes, and others are projects I am working on for friends. Most are built with my Tormach PCNC 770 mill. I am still learning how to use it and also trying to get up to speed on BobCad - the CAD/CAM package I am running.