lathe
Having Fun in a Micro Machine Shop
I currently sit on the edge between micro-machining and mini-machining (Proxxon PD400), owning and using both size ranges. For me, I am in the perfect fit with these options as (within reason) it is better to be a bit larger than you need in a machine than to push a small machine beyond its inherent limitations. But small micro-machines are totally capable when used properly.
I am well aware I am not the best micro machinist living on the block. I have seen some outstanding work produced on these tools and I know the time it takes to get to those levels of perfection. My honest excuse is I just don’t spend the time at this point to reach ultimate perfection, but I try to do my best for the time involved.
In micro machining, all the same moves are required as in making a big part. The touch and feel are a bit different but the level of fun and enjoyment of the work is in my opinion very much the same. A few big points of difference are the cost of materials and the working room and electrical power required.
Micro machining usually falls into the model making… Continue reading
New Visitor Posted in THMS
Mini-Lathe 21 tooth change gear.
I received a 21 tooth gear in my mini-lathe upgrade gear stock shipment by error. At first I didn’t know where it could be used. None of the stock gears in a mini-lathe are 21 tooth. (See picture).
The upper 20 and 25 tooth gears are a part of the reversing system. They are small bore with no key way.
The lower two 20 tooth gears in the picture have a larger bore and a 3mm key way. So do the 21 tooth gears I accidentally received. I thought the 21 tooth gear may have something to do with metric threading.
I did some research and I found the identical 21 tooth gear recommended for replacing one of the 20 tooth gears to get closer to cutting certain metric thread sizes. Which one depends on the thread desired. Only one (1) 21 tooth gear is required. Both 20’s are used for some threads.
The mini-lathe because of it’s 16 TPI lead screw can never make all metric threads exactly on pitch.
So the mystery gear is no longer a mystery. The original 20 tooth gears are steel so they are not replaced in my upgrade kit.
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