Lathe

Lathes

Hacklab currently has two lathes:

1. Craftex B1979C (7x8") - Operational
2. Sherline 4400 - Operational

Safety and Cleanup

Safety

If you do not know how to use this tool, do not attempt to use it.

Set-up and general

The lathe should both be powered off and unpluged when:

• If you have to leave the lathe unattended, or you are done using it.
• When changing tools, adjusting chuck, or any other lathe maintenance.

Operation

• PPE (Safety glasses) must be worn when lathe is in operation
• Avoid wearing loose clothing (including gloves), wear proper shoes, no loose hair.
• Avoid positioning your body in parallel with the chuck.
• Ensure the chuck keys and other obstructions are removed from the lathe before powering it on.
• Files must be used with a handle, and both ends of the file must be held.

Cleanup

The lathe has a tendency to make a decent mess. Please do your best to clean up the area around the lathe after you are done using it. This includes:

• Wiping down the ways, saddle, etc to keep the lathe clean
• Cleaning off the workbench from metal shavings etc.
• Sweeping the kitchen around the lathe area to prevent people from gathering shavings with their feet.

B1979C

This is the bigger of the two lathes. It was lying in a large pile of wood shavings at the Toronto Tool Library so Misha took it (and brought it to Hacklab) with their permission. Misha also works at the company that sells and services that lathe so ask him if you need anything.

Caution

This lathe is missing safety shields. Wear eye protection!

Brief Intro

There are many ways to use a lathe. Traditionally, you put the work piece in the chuck and a tool bit cuts away metal down to the desired size. The tool bit is held by the tool rest (the square thing with eight machine screws) and held down with machine screws. The cutting part of the tool bit should be at the same height as the centre of the work piece, or up to 0.005" higher to compensate for deflection. If the tool bit sits too low, you must use shims to raise it. If it's too high, you can mill it down to the right height (though in the case of HSS, it's easier just to buy a smaller tool bit.) The tool rest we have has space for four different tool bits and it can rotate to switch between them or change the cutting angle. Always secure the tool bit as close to the tip as possible, to reduce deflection.

The speed of the lathe can be controlled by a dial on the headstock. In theory, the correct speed is a function of the material being cut, the max. diameter, and the tool bit type (see below). Usually it should be on the low end for steel and stainless, medium for aluminum. Smaller pieces and softer materials call for higher speeds.

The lathe should not make chattering and grinding sounds, if it does, you need to use the correct speed or sharped the tool bits.

Tooling

There are three main types of cutting bits: high speed steel (HSS), brazed carbide, and indexable carbide. HSS is the shiny home made looking metal tool bits, brazed are blue with a grey tip, and indexable have screwed on triangular tips.

We have a small set of indexable carbide cutters, but I suggest starting with HSS. As you cut, the tool bit will become dull and you will become frustrated. If you use HSS, you can use the bench grinder to sharpen as often as you like, which will keep both you and the cutter happy.

Lubrication

Lubrication helps, but if you find yourself needing to flood the cut with oil then you might be doing something wrong. It should cut OK with even a little oil.

Threading

The lathe can cut nice threads but the gears need to be changed manually. Each gear is stamped with the number of teeth (except the smallest one - 20 teeth). Use the chart on the lathe to choose the correct gears for a certain screw pitch. There is also an option of setting a very low gear ratio for power feed. It is not intended to cut threads. Depending on the desired gear ratio, there may be one or two idler gears. The idler gear(s) needs to be adjusted on two axis so that it is contact with both other gears. Do NOT use the little nylon gear, this is meant for threading left handed screws and is part of a completely different gear train (not sure why it was removed but if you know what you're doing, feel free to re-attach it.) Trying to put it onto the screw gear train will end badly because it has no keyway for the metal tongues. In case you were wondering, I suspect the reason why two gears are made of plastic is in case someone tries to engage the leadscrew while the lathe is running (don't do that!), the little plastic gear will be sacrificed.

Some of the gears are a little hard to fit onto the shafts, so you may have to knock them out with a mallet and press fit the new gear with the vice. Please be gentle when doing this!

Issues

The belt on the lathe tends to wear out after a while and will eventually need replacement. Ask Misha if this happens.

Extending the lathe

Misha's DIY Projects for B1979C

• Thread indicator
• Radius cutter
• Milling attachment
• Dead centre (we have a live centre)
• Power handle
• Tool bit sharpening jig
• Gear cutting

Wishlist

• 4 Jaw Chuck
• Milling attachment
• Faceplate
• Boring bar
• NPT threading attachment
• Steady and follow rests
• Parting tool