Help-what is reasonable?

Mine was (today!) a stubby little 4-flute 1/4" I picked in the same auction as all the other bits and pieces. One of the flutes is chipped at the tip so forget face milling, but it worked a treat as a side mill - after I cut a little slot which would normally take me 4 times as long to do otherwise and looking at the quality of the finish I was sold...

I did learn more lessons though, such as that good clamping in a vise is necessary - I was trying to side mill one of the faces of the piece (itself tiny - 5/16" square and 1" long) and the mill just lifted the piece out of the vise.

Also do not ignore your wife if she tells you that you are climb-milling instead of conventional - she has been watching the same DVDs and paying attention!

When you're working on short pieces, having to machine an end, it's always a good idea to have a second piece on the opposite end. If you're working off parallels, the piece can even sit on the bottom of the vise, just as long as it's there to absorb the clamping effort. That way the jaws will clamp parallel and have much greater holding power. The pieces should be identical in thickness , so the jaws old parallel. Keep them separated as much as is possible for effective holding power. If you have them both on the same side of center, it won't work worth a damn.

You have a keeper! Many women do not support their husbands in these endeavors. Like you, I'm fortunate to have one that does.

Harold

I trust part of the modification was to grind the perimeter of the drill?

Drills are circular ground, and not backed off, unlike an end mill. As close as they get is to have the lands narrowed, to minimize contact with the hole. While you can get them to cut, they do it with considerable protest. You'd have less than acceptable results with tough materials.

Harold

I suggest you keep it and learn its capabilities and limitations by using it. If you eventually find that it's inadequate you will know much more about what you really need, and what to look for.

Most of my commercial machine shop work has been for electronics and optics, typically sheet metal or thin aluminum plates, rarely as much as 2" high, and not usually requiring better than 0.005" accuracy. I did some of it on a mill drill, some on my Clausing, some on a similar Enco 100-5100 knee mill

My home projects are more 3-dimensional and really need the extra vertical travel of the knee. If I had the space I'd buy a Bridgeport.

Don't give up on the chipped end mill. It probably still works for facing if you feed slower, since only one flute is cutting. The chipped edge got shorter, not longer, and shouldn't scratch the work. You can salvage a broken one by grinding the end flat, then copying the 5 degree and 30 degree (roughly) angles of another end mill freehand on a bench grinder or belt sander. The cutting edges should slope slightly inwards towards the center so only the tips cut as you feed sideways. One flute will of course be longer than the other and do all the work at the bottom of the cut, so feed slowly.

If you need to mill a blind pocket with it, drill a starting hole almost full depth and then run the end mill down it. You can deepen the pocket slightly to reach finish depth by lowering the end mill very slowly as you feed it sideways.

Once I have a replacement I use these degraded end mills for roughing out deep slots and steps, and taking the first cut on mystery metal. I can resharpen them correctly on my surface grinder and have been using one pair of salvaged high-quality end mills for 15 years, saving the new ones for finish cuts. I only hand-grind broken ones when it's a rush job, someone broke the size I need, and a purchase order to replace it takes 3 weeks. Small company shops can be even more restricted than a home shop because both time and money are limited.

If you can't follow Harold's valuable advice on clamping, pad the moving jaw with a piece of wood to spread the grip area and keep the cuts light. I do the end facing first and use the cut-off remainder of the stock to balance the vise.

Jim Wilkins

The important distinction to make is what is inadequate: the machine or the operator :-)

In its current state even the chipped mill exceeds my abilities to do the job otherwise. It is going to be heavily employed for finishing a few stands for the dials until the new set arrives

This is something I shall have to consider learning. I have never needed to sharpen drill bits as they are cheap and plentiful.

The case in question was even worse than that. I am ashamed to admit that I clamped the workpiece the way I would have done for drilling in the press - in the top groove of the vise. Not surprisingly, the grip area was very small. When I spotted the error I reclamped using some of the lathe tools as parallels and managed OK. However, Harold's advice is indeed valuable and will be followed in future.

I trashed the first end mill I used, then learned not to push them so hard.

The operator seems very open to advice. I learned the essentials of machining by working in factories and much more by taking night classes at the Voc-Tech. The first shaft I needed to thread cost me $40 in tuition to get time on a good lathe.

I was working with very little depth of cut so got away with it. Gerry :-)} London, Canada

I trashed the first end mill I used, then learned not to push them so hard.

The operator seems very open to advice. I learned the essentials of machining by working in factories and much more by taking night classes at the Voc-Tech. The first shaft I needed to thread cost me $40 in tuition to get time on a good lathe.

Another trick for when you don't have another piece of the same dimensions is to use an adjustable parallel set to the same size to place in the other side of the vise. They are fairly expensive, though, so be careful not to mill them while milling the workpiece. :-)

They can also be used to support one side of a workpiece which has two different heights.

Enjoy, DoN.