Thursday, June 28, 2007

3D Doodling

I'm presently in the final stages of my move. Jury Duty didn't help either. It's been a long and arduous week. Anyway since my shop is in boxes right now, I decided to reacquaint myself with Rhino 3D to keep my sanity. I have an older version (2.0) which came installed on my used laptop. It works fine for me. I decided to work on a design for an I.C. engine just to challenge my brain. This is what I have so far:

It's a concept only so far although the proportions are close to what I want. As you can see its a 4 cycle engine with a belt driven camshaft. Obviously it's missing a few details still but I have quite a few hours into these drawings. I'm thinking 1/2" bore with 3/4" stroke and 2.5" flywheels. A nice size envelope for a Taig. Hopefully in the near future I can start on some working drawings.

Friday, June 8, 2007

Let there be swarf....

I've been in limbo with my machining endeavors due to an impending move. Budget was temporarily derailed by this. Good news is that I will finally have a garage to play in. I should be moved by the end of the month. Continuing with my lathe buildup and tooling, I received my 4 jaw independent chuck and right hand cutter yesterday. I cleaned the 4 jaw chuck out and reversed the jaws so I could try a few test cuts. I installed the new cutter in the tool post. **CAUTION- The cutter comes with a plastic covering over the the sharpened end to protect it from damage during shipping. Be very careful when removing it; I gripped and pulled the cover off the end with my right hand fingers and promptly cut a nice 1/4 slit on the tip of my index finger. These tools are very sharp!!! Be safe.** I have a 2 foot length of 1/2" hot rolled steel rod laying around so I figured it would be a great test for the lathe. I cut a 3" piece off and chucked it up. I used my dial indicator to get it as true as possible. I set the tool bit cutter edge parallel to the rod and then did some light facing cuts on the end of the rod. I played with speed and feed to get the best results. It took about ten passes to get the facing done (lousy hacksawing technique!). I am new at this so I'm learning as I go. I then proceeded to do some regular turning on the rod. I set the carriage stop rod a safe distance from the chuck. I started with a light cut and was surprised to get some significant chatter. I played with the speed and feed with little improvement. I started wondering about the capability of the lathe until something dawned on me; I forgot to reset the angle of the tool holder after facing the end! It would take a lot of power and rigidity to make any cuts with the side of the cutter! After resetting the tool, swarf started flying!

Yep, that's some swarf there!

I was able to reduce the rod a few thousands with a nice smooth surface. It's going to take some practice to learn how to turn the handles smoothly though. I think the addition of a leadscrew is going to be very beneficial in this respect. Also, I'm going to design some kind of larger handle for the crosslide. There are a few issues I noticed with the lathe operation. The crosslide is noticeably tighter when moved towards the handle. After checking it out I can see that when the handle is turned counterclockwise, the dial assembly is pulled against the bearing block assembly significantly increasing friction between the two. Therefore the handle is harder to turn. When turned clockwise, the opposite occurs, thus the handle turns very freely. Maybe some kind of thrust washer can be used or maybe lapping of the dial/bearing block interface. I'll have to see. I also think that i need to spend a little more time lapping the crosslide to the carriage assembly to smooth it out. I'll be busy over the next few weeks with the move but I'll be definitely be working to resolve all the issues.