"One Perfect Part at a Time"


PD400 Tail Post Clamp

I purchased the adjustable control handle and bolt more than a year ago when I was rebuilding a camera head mount for my daughter. In fact I bought several with the proper bolt size for this application. I was going to experiment a little.

As you can see in the third picture, the original Proxxon PD400 design uses a simple socket hex head bolt for use with a large hex wrench. Of course the wrench can fall out of the socket and is always difficult to find when you need it.

The handle shown was a bit too “fat” to just replace the bolt. So today I did a bit of minor grinding of the tail post to provide clearance for the “fat” part of the handle. About 15 minutes work with a Dremel type tool and the handle fits perfectly. I can’t even see the grinding area.

The handle is spring loaded so the position can be easily adjusted by just pulling up on the handle and re-positioning.

It works so wonderful I can’t imagine why Proxxon didn’t do this as a standard assembly. Actually, I can’t understand why I waited so long to make this simple modification.

Big Lift

Is this a "Bench Press"?

I had to laugh at myself this week end. As usual I was pushing myself too hard and for too long in all the heat. Texas is having a very long spell of 105 degree weather. The high temperature must have made me wacky.

I know my PN has sapped most of the strength I used to have in stamina and ability to dead lift and carry things. Put the PN and the hot weather together and it doesn’t make for a good combination.

So my problem is how do I know my limits until I test them? I push hard enough to find those edges.

I have a small mini-lathe (a metal cutting machine tool) for which I sell conversion gears to buyers all over the world. I stored the machine on a bottom shelf of one of my work benches. It is made of cast iron and steel and weighs about 75-80 pounds.

Let’s say I used to be able to pick it up and move it. Well not any longer. That is now a limit I shouldn’t exceed. But I had to test that fact to be sure.

I was pretty sure this wasn’t a good idea but I didn’t let that stop me. I pulled the lathe out onto the floor off the shelf. Then I got what I thought was a good grasp and tried to do a power lift with my legs. I know my back is not good so I was looking out for it. Well, the legs are no darn good either.

I did not hurt myself other than my pride. I got the machine about a quarter the way up and my legs decided to quit. I sort of rolled back against the bench then off… Continue reading

“Proofs” of Concept

I was doing some product research today. This is something I made in about five to six hours. I had been thinking of how I was going to make these all week. I just needed a good Saturday to give it a shot.

As the title indicates this is a proof of concept not a real project. I didn’t want to slow myself down doing all the pictures of the process. The process is still experimental so  full disclosure can wait until a better time. I have my camera at the ready.

Long time readers know I have experimented with pewter casting before. Here is the LINK.

The “thumbs up” graphic is a 3-D rendering received free with the Vectric Aspire software. I used it to create the medallion. The finished result is seen in the first picture above. The picture was created within the software. I combined the thumbs up with some freelance drawing to form the disk. Actually in my opinion the disk is much thicker than it should be.

The edges of the disk did not come out well in the tool pathing. I need to find a better way to create the disk in the software. As this was a trial, I didn’t want to spend all day on the drawing so I accepted some imperfection in the edge rendering and moved on.

Next I had Aspire produce a roughing toolpath for a 1/8 inch ball nose mill bit. Then I had Aspire produce a spiral finish pass with a 5/32 inch ball nose. The disk is 1-1/2 inches in diameter. The aluminum (both pieces) is 1/4 x 3 x3 inches. The back plate is not machined in this test trial.

The machining was done on the CNC Taig mill. A… Continue reading

Weighty Subject

A fellow ham radio operator Dennis (KI4DW) was in need  of replacement weights for his Brown Brothers “bug” keyer. The weights are the easy part. I thought he needed the thumb screws duplicated too. Turns out he has the screws.

The weights I turned from a 3/4 in leaded steel bar on the PD400. The slots are cut with a 3/32 end mill on the X3. The digital readout was a real big help in free handing the slots. (CNC automation spoils me.) In the picture, the slots still need a bit of internal filing to square the inside corners.

The 8-32 thumb screws would be a lot more work to make exact copies. I was afraid of the time (and cost) I would spend on two of them. I have since discovered a good source for these at McMaster-Carr.

If I make any more weights, about a half hour in BobCAD should make the slot cutting easy work starting from dead center. Heck, the G-code would be easy to write from scratch.

Just a few hours work on developing these parts. CNCing the slot would make it much faster to produce more.

Letting the Cat Out of the CAD

BobCAD LogoI am taking an opportunity in my project schedule to try another CAD/CAM package. I had looked at it long ago and it has been around for over 25 years. When I first saw it (back then) I believed it was one of those,”yet another CAD/CAM packages.” I am sure at some point I registered and ran at least the demo, as it seems I have been receiving occasional marketing from them forever. Back in that time, I was looking for a cheap all in one CNC solution. I was still a bit naive of all the requirements. I did find and purchase DeskCNC with its serial port interface. That worked OK but I am now using much stronger and expensive Rhino and Vectric 3D software and MACH3 from ArtSoft. You get what you pay for.

The product to which I am now referring to is BobCAD-CAM. I knew it was created by a guy named Bob (Bob Twaalfhoven) so I assumed he just called it BobCAD after himself. I was thinking simplistically it was Bob’s CAD. Today it is a more professional play on the image of a Bobcat, just change the T to a D. Whatever the thought on the name, it has survived the test of time.

Soon I will see if it survives the test of Dan.

DeskCNC is still around too but the web page has changed little to none. BobCAD-CAM is on version 24 and a first web site look, while allowing for marketing hyperbole, seems impressive.

It will take me a few weeks or a month or so to give it a full workout and use it to construct a CNC project. I’ll probably leak a few comments here in the blog, but I am considering doing a full report, probably… Continue reading

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