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MachinistBlog.com

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

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.

Making Particle Board Workbench Tops

This article describes how I make workbench tops using particle board.  I’ve been using this method for about 20 years with good results.  Although the next time I build a similar bench I may use a laminate counter top for two reasons, which I’ll explain later.

I don’t like benches that move, shake or vibrate.  I think the heavier the frame and top are the more stable a workbench will be and the better it will dampen vibrations.  Particle board is very heavy which is why I like to use it.  To make it even heavier and stiffer I glue two 3/4-inch layers together.  Particle board is also very dense, unlike plywood and MDF,  which means it won’t dent very easily or much if you hit it with a hammer or drop something heavy on it.  It’s also inexpensive and it won’t warp.

I’ve tried using plywood but it dented and splintered easily.  Wood planks will do the same.  Plus planks can warp and it’s not easy to build a smooth seamless work surface out of them.

Construction

I built the L-shaped bench shown in the picture a couple of years ago.  The frame was built with 2x6s instead of 2x4s to make it strong enough so I could eliminate all but two legs and keep the space under the bench unobstructed for storage.  The legs are at the ends and are made from pressure treated 4x4s.  I began construction by screwing the back rails to the wall studs.  I made certain they were level and used screws that could support a lot of weight.  Then the front rails, side rails, legs and cross braces were added.  I used metal joist hangers, angle brackets and deck hardware to fasten them all together.  They added to the cost but I think they made the bench much stronger and quicker to build.

You might want to bring some help with you when buy the particle board because 4×8- foot sheets are heavy.  I got Home Depot to rip them in half lengthwise.  It saved me a lot of work and made the boards easier to handle to bring home.  If you have them do it make certain they measure correctly.  The first sheet they cut was off by 3/4-inch and I wouldn’t accept it.  They very graciously cut another.

This L-shaped bench top was harder and more complicated to make than a simple rectangular one.  I began by fitting the lower-layer pieces against the walls.  Then I cut and glued just one of the top pieces so it overlapped the seam in the bottom layer. When the glue was dry I fitted and glued the remaining piece, making certain that it butted very tightly against the other one.  I also made certain it was well clamped and weighted down while the glue dried.  I ended up with a very tight seam that only needed a little bit of wood putty to make it disappear completely.  It’s still invisible two years later.

I used the “original” Gorilla Glue to glue the particle boards together.  There might be cheaper alternatives but I wasn’t going to take any chances on the seam between the two layers coming apart.  This kind of Gorilla Glue is water activated and you’ll need to use a spray bottle or wet rag to slightly dampen the surfaces just before you apply it.  I used a plastic spreader to spread it out evenly.  Then I used lots of clamps along the edges to make certain I got a good bond with no gaps.  I also stacked as many heavy objects as I could on the rest of the bench to weigh it down.

It’s not likely that you are going to get both layers of particle board cut and lined up so the edges are perfectly even.  So after all the glue was dry I used a router with a flush cut bit to make them even.  This may require positioning your router on both sides of the bench top.  I couldn’t do that because there wasn’t room to flip my L-shaped top upside down, and the support frame prevented me from holding the router upside down against the edge.  So I had to plan ahead and make certain that the top layer extended beyond the bottom one a little bit so the router bit could trim it flush.

I then used the router with a 1/2-inch round-over bit to round the edges of the workbench.  It’s a little bit more work, but I think it makes the bench top look more finished and professional looking and it makes the edges more comfortable to lean against.  Rounded edges also won’t dent or splinter like sharp ones will if they get bumped with something heavy or sharp.  They’re not hard to make but I recommend practicing on scrap first. Continue reading Making Particle Board Workbench Tops

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

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