Cheap Mini Mill

ex_isp said:
Reasons please.
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Studying the images of the "Mill" the column is attached to the "table" by four screws, approximately the size of a 6-32 screw, certainly not as big as 1/4 - 20. Comparing the mass of the column vs the mass of the 'table', I'd be afraid that instead of vibrating during a cut, it would lean to one side or the other. It is not built heavy enough to be called a mill. Machining even 1/8 brass would overload it's rigidity.
 
Going to that fleabay sight and looking at the examples it can make. They are all made out of wood and plastic. The spindle speed is 2K rpm. I’ll bet that vise is made out of plastic. It has leave it and run away, written all over it.
 
Well, I thank you guys all!!! I looked a little further and found an 8 yr old large/HEAVY (150 lbs) HF machine that came with 16 collets (1 of them has a chuck in it) that has been in use by a pro gunsmith since new.
When I got to Tucson from Phoenix, he said he was hoping I wouldn't show up for another hr as he was still using it. He was using it to cut dovetails in pistol barrels and loves it but he's 78, retiring and moving to Louisiana.
So, 8 yrs ago, this was an $800 machine with what he described as $200-$300 worth of accessories.

I got it for $400 and a half tank of gas. I'm delighted and glad for the strong suggestions to get something a little bigger. Next couple days I'll get some photos of it and shoot them up
to my photobucket so "ya'll" can see which one it is. Guy was cutting pretty tough steel with it when I got there and it was not complaining at the load.

Thanks to all!

Chris
 
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Today, I did a test cut in the brass with a 1/8" dremmel bit in the collet as I don't have real cutters yet. Was able to chew through over 50% of the 1/4" thickness of stock
in a single pass with no strain at all. I'm impressed and must agree, the Chinese ebay machine would not have done that. Again, THANKS for pushing me towards the
larger machine!!!

Here's the machine and accessories that came with it. I think I stole it for $400.

IMG_0470.jpg


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Hey ex_isp good find! When I was looking for a mill a couple years ago there was not much to be had somI got a PM-25. Are you part of the Valley Metal group? If no send me a PM and I can get you information about the group. It is a nice bunch of guys that shares ideas and helps eachother out.
 
I've seen this gib screw arrangement on Asian machines before. In fact, my Emco lathe has divots for the gib adjusters too. They allow for adjustment and a method for keeping the gib from moving, all at the same time. The difference is in how this is executed.

On my Emco, the divots are machined carefully and precisely at 90 degrees, and coned inserts fit into those divots; the gib screws bear on the back of the inserts and not directly on the gib. The benefit, obviously, is that this arrangement does not distort the holes in the gib. The pic below shows the inserts on my compound gib; the one on my saddle is the same. The insert shown fits in a vertical slot that locates the gib and keeps it from sliding around; the rest of the gib screws are in coned holes, not slots.

gib screw.jpg

My Rong Fu mill has gib locks that are the same as the mill in the article. When either the Y or X axis is locked the locking screws actually screw down on the gib, digging into the back of a cast iron gib. If I lock it really hard there is a risk of damage or possibly cracking the gib. To get around that I made inserts with noses ground at the angle of the gib in front and flat in the back. They slip into the gib lock holes and the gib locking screws bear on the inserts. Now, when I lock the axis it locks solidly and I'm not concerned about damage or cracks.

Some guys use ball bearings instead of tapering the nose of an insert and that works well for gib locks, not for gib adjusters. Anyway, food for thought.
 
More great information Mikey and thanks!!!

Today, now that I'm starting to get some bits in, I decided just to play and make myself a fancy bit holder.
Sorry it's blurry, was holding cam with one hand and light with other. This is a piece of Maple burl that I
really like for my knife scales, but it's too small to use for that, so...

BitHolder.jpg
 
Those look like burrs. I assume you have some end mills coming for your brass slotting work, too, right?

I love burled wood - beautiful patterns that only nature can make.
 
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