Posts
Comments

MachinistBlog.com

Plans, projects and how-to's for home machinists

Video: Centering a 4-jaw chuck

This is probably the best video I’ve ever seen showing how to center a piece of round stock in a 4-jaw lathe chuck.  I am wondering about one thing though.  Some of the commenters on YouTube refer to centering the chuck the “normal” way.  Well, what is the “normal” way?  This is pretty much the way I do it, although I still haven’t gotten around to making a second chuck key yet.

HSS Indexable Inserts

It’s not obvious at first but this video is about the Arthur R. Warner Company’s HSS indexable inserts.  After seeing it I’ve decided that I would really like to give them a try.  I know you can get a better finish with HSS bits but I don’t like having to stop to sharpen them.  So I use carbide inserts.  I get a pretty good finish with them and I can cut with a tip for hours before it wears out and I have to rotate the insert to a new one.

It looks like the Warner Company’s inserts give you the advantages of HSS along with quick and easy sharpening.  When a tip on the insert gets dull you can rotate to a new one in seconds without losing your lathe bit’s position.  And when all 3 tips become dull you can sharpen them by rubbing the top surface of the insert on a whetstone for a few seconds (see video at 2:30).

Unfortunately, they don’t seem to sell inserts that will fit my tool holders (TCMT32.52 for my 8×12 and TCMT 21.51 for my 7×12).  So if I want to give HSS inserts a try I’ll have to buy a 5 bar turning kit for about $128 or somehow find the time to make a bar that will fit their inserts.  The price of their kit is considerably more than what I paid for my imported insert holders but it seems reasonable for a quality American made product.  Has anyone bought one or tried their inserts?

5-axis machining

I wonder if we’ll be able to buy an affordable hobbyist version of one of these machines in 10 years?

CAM program D2NC’s new features

This is a very quick introduction to D2NC, the CAM program I use to convert DXF files into G-code for my mini-mill.  It also does conversational CNC programing and it has a “Shape Description Language” for creating shapes and tool paths.  D2NC only costs $79, which seems pretty inexpensive for a good CAM program.  It costs even less if you buy it with a Mach3 license.  There’s also a fully-functional demo version you can try free for 15 days.

The video shows the pocketing, ramping and tab features that were just added to the latest developmental version, which may become the stable version soon.  It also shows how easy D2NC is to use, which is one of the reasons why I bought it.  The excellent videos, well-written documentation and the help that is available from the D2NC discussion group were another reason.

For those of you who aren’t familiar with computer-aided manufacturing programs I’ll quickly explain what they do.  A CAM program takes your CAD drawing and creates G-code instructions for your CNC mill (or whatever) to run.  But to do that it needs a little help from you, especially if you’re working with 2D drawings.

Imagine a CAD drawing of a flange that is a simple square with a circle in the middle.  The CAM program sees the circle but it doesn’t know if you want to cut it out, drill it, pocket it, raise it by milling the material down around it, engrave it or whatever.  Similarly, it also doesn’t know what you want to do with the square portion.  So you need to tell it and also what size and shape cutting tools to use and what feeds and speeds to use.

For me, finding and learning how to use a good affordable CAM program has been the hardest part of learning how to do CNC machining.  So I think I was lucky to find D2NC, which is kind of a well-kept secret even though it’s been around for at least five years.

Random Quote

Two months in the lab will save you two hours in the library.

— Unknown