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MachinistBlog.com

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

A Southbend movie about single-point cutting tools

I’m posting this video for a couple of reasons.  First, I often enjoy watching movies from this era and I thought some of you might too.  More importantly, it contains knowledge that is still true and useful more than 70 years later.

Make Your Own Machinable Wax

Make Your Own Machinable Wax

For those of you who aren’t familiar with or don’t want to pay for machinable wax, this article on what it is and how you can easily make your own if you want to make your own should come in handy.

Some things about machinable wax

  • It can be a cheaper and better alternative to metal, making it ideal for when you create your prototypes. One member from the MadModder community made a prototype of a dry sump unit for his BMW V8 using machinable wax, which saved him from using his expensive metal.
The Machinable Wax Slab, Early Stage

He starts with a fairly basic (and fairly large) piece of machinable wax. (Photo courtesy of MadModder member, AdeV)

  • Machinable wax won’t damage your cutters or CNC machines. It also won’t cut fingers, which might be good if you’re teaching kids or giving a demo
  • It’s recyclable, meaning you can keep re-melting broken pieces and shards
  • You can make your own with inexpensive and easy to find materials

Since machinable wax costs anywhere from 12 to 350 (usually for industrial-sized quantities) dollars, taking some time to make your own will save you a few bucks.

What you need

  • Paraffin (candle) wax. This can be bought at many arts and crafts stores
  • Items made from LDPE plastic. Things like plastic bags and milk jugs work, but there’s a more comprehensive list is on The Home Shop Machinist & Machinist’s Workshop Magazine forum
  • Something to boil the ingredients in safely, like a double boiler or an electric fryer you can use outdoors

You’ll notice that the ingredients and equipment listed is easy to find or readily available. A few machinist forums and groups offer different variations of the recipe, but of all of them, the MadModder forum gives the best instructions. The Weaponeer forum also has a pretty decent recipe in PDF format.

Safety precautions

There are a few things that need to be kept in mind before performing this task:

  • You’ll be working with high temperatures and wax, which can cause serious personal injury or property damage. The 7×12 Mini Lathe group offers an interesting discussion on some excellent safety tips so you don’t hurt yourself or burn your house down

Take it as seriously as you would with any aspect of machining.

Whichever recipe you choose, it may take a couple of tries before you get the perfect wax, but once you get to that point, you’ll be saving money and making your own machinable wax in no time. Continue reading Make Your Own Machinable Wax

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.

Tubalcain’s Lathe Bit Grinding Videos

Even though YouTube seems to have umpteen million videos about machining I’ve found very few that will you show how to grind HSS bits for a metal lathe.  And most of them show it being done on special grinders or with the help of jigs and accessories that most of us don’t have.  These four videos by Tubal Cain, the author of many books about machining and metalworking, are among the few I’ve found that will show you how to do it free-hand on the kind of grinder most home machinists have.  [This is not the same Tubal Cain who wrote more than 20 books and 200 articles about machining and model engineering.  That was the late Englishman T. D. Walshaw who used “Tubal Cain” as a pen name.  This “Tubalcain” appears to be a retired shop teacher living in Illinois. – Rob]

The videos are good, but not great because they’re too long.  “mrpete222” doesn’t get to actually showing you how to grind a bit until the fourth video.  During the first three he discusses the shapes and angles of the various kinds lathe bits using large wooden models that make it easier to see what he’s talking about.   He also discusses the tool bit holders used by older lathes, which hold bits at an angle so they don’t need back rake added to them.

I’ll admit I’m not real good at grinding lathe bits because I usually use carbide inserts.   But I did learn a lot from these videos including these two great suggestions:

  • Use lay-out dye and mark out the angles you need to grind.
  • Practice on mild-steel (keystock).  It’s cheaper and grinds faster.

Links

Lathe Tool Bit Grinding Video #1 (10:46) – Right-hand turning tool, back rake & tool holders, angle of keenness

Lathe Tool Bit Grinding Video #2 (5:13) – Facing and universal turning tools

Lathe Tool Bit Grinding Video #3 (5:39) – 60-degree thread cutting bit

Lathe Tool Bit Grinding Video #4 (8:46) – Actual grinding of right-hand turning tool

Random Quote

Truth is more of a stranger than fiction.

— Mark Twain