Member postings for Ronald Morrison

The fact that the lathe motor can be run in reverse makes threading to a shoulder for imperial threads much easier. With the motor running in reverse use a boring bar with a thread cutting end on the backside of the stock , bring it to the shoulder, then engage the "half nut'. Now you cut threads away from the shoulder so you don't have to have lightning reflexes. Making a stop for the carriage lets you set the starting point so the tool never hits the shoulder.

If your eyesight starts to go bad the fact that you have to replace a battery occasionally will not bother you so much as not being able to see the numbers on the dial nor the lines on the vernier. I have to replace the battery about once a year on each of my digital calipers. Since I know that, I keep a few spares on hand.

Why not save yourself the agonizing over the metric dial caliper and just get a digital? The cost is not much different, the digital has numbers big enough to read and with a quick push of a button becomes an imperial caliper. Very easy to set a new zero as when you are turning to a specific dimension you can set that dimension as a zero and read how much needs to be removed to get the intended dimension.

I also didn't know what I would be using the lathe for but I inherited a 10X24 inch Chinese made lathe with a gap bed. Now that I have had it for several years I know what I would use the gap bed for as I did need it for one project. It came with a steady rest which I also have found a use for. Bigger is better in my mind because I can still make little parts on a big lathe but no big parts on a little lathe. With that in mind, space available and how to handle the weight of the lathe getting it to that available space must be considered even before checking your wallet to see if you can afford it.

Does the CNC he desires need to be able to cut metal? Would a wood cutting CNC machine satisfy him for a while? How about helping him build a CNC router? With that approach he/you can save some money and have a better understanding what it takes to make a CNC machine. Knowing that will set him up to be better able to understand and use a CNC mill. Here are a couple videos on making one.

Do it yourself CNC

$500 home built CNC router

How fat is your wallet? Ideally you want a power supply that can produce 24 volts (motor is rated for that voltage) and infinite amperage. That would keep the voltage constant over any load possible. Now you know that the motor can only draw 11 amps maximum so in theory a power supply that can produce 24 volts and 11 amps should be sufficient but in the real world, as the power supply approaches that maximum load the voltage drops. I'd probably be looking for a supply that could produce twice the rated amperage as that should be fully capable of maintaining the voltage at 24V but then I would compare that supply cost to how my wallet looks and think about a compromise. How often would I need that full power? What will be the consequences if the voltage drops a bit under full load?

Speed control technology has rapidly advanced such that what is available for speed control for DC motors now wasn't available when the book was written. What was normally achieved by changing pulleys can now be adjusted with the turn of a potentiometer. The advent of technology to create brushless motors with high performance is quite new also, again probably since the book was written. It is also possible that the author has a bias.

Put an endmill or fly cutter into the spindle of your mini mill and measure the distance to the bed. Now subtract the height of the vice you mentioned from that to see what size of material you can fit into the remaining space. You may decide that the swivel base will take up too much of the space available for the amount of times you will benefit from the swivel.

Rigidity is critical in removing metal with a lathe bit, boring bar, or a milling cutter. The typical boring bar will be steel. Hardened steel is more rigid than mild steel but solid carbide is even stiffer. Look for the solid carbide boring bar.

Here is what those kind of lathes sell for new in the United States.

https://www.harborfreight.com/7-inch-x-12-inch-precision-mini-lathe-93799.html?_br_psugg_q=mini+lathe

Select the white wheel instead of the diamond unless you are only grinding carbide or are using it in a low speed grinder. When using diamond for grinding steel where the steel will become hot the diamond (pure carbon for practical purposes) can dissolve into the steel increasing its carbon content but leaving little cutting action from the diamond.

Delrin should not need lubrication buy shouldn't be harmed by lubrication either.

Snug up the gib while trying to turn the handwheel. Do each gib screw and make sure the screw is slightly snug but does not bind the handwheel. The handwheel should still turn relatively easy but not freely. Hard to explain better without being there.

1. Check that every gib is adjusted to get a slight drag. Don't expect the manufacturer to have adjusted everything to the best fit. Loose fitment on the cross slide and compound will get you bad results.

2. Sharp tools make accurate cuts. Dull tools push the steel instead of cutting it. Carbide inserts have their place. They are made to be able to withstand higher temperatures that come with high RPM and heavy feeds. They cannot be super sharp because they are brittle and the edge will chip. If you want super sharp so you can make very light cuts use high speed steel and learn to grind the proper shape and to hone it to razor sharp.

3. Back off the tool from the steel before backing the carriage for the next cut.

i put off buying a bandsaw for years, using the hacksaw for all my small cutting and oxy-acetalene or plasma for the bigger cuts. What a mistake! Now that I have a bandsaw I will carry parts 100 meters to the bandsaw instead of picking up the hacksaw that is 1 meter away. The accuracy of the cuts is better than I ever managed with the hacksaw and I can clamp the stock in, start the bandsaw and walk away to do other things, knowing that the bandsaw will just shut itself off when the cut is done.

I have a terrible time threading up to a shoulder as I can't seem to stop the carriage just at the right time with the motor turning the spindle so I made up a crank that would turn the spindle. That lets me turn the spindle very slowly, much slower than the motor will go and I can then stop the turning just where I want.

Thingiverse doesn't prohibit posting the CAD file in with the STL but most people don't care to make changes or the person posting doesn't want others to make changes so they don't upload the CAD file. When you see an item you want to modify, the maker's name is on the top of the first picture. Clicking on that name opens an "about" page with a place at the bottom to send a message. Asking for the CAD file would be my method for starting to modify.

Take a look at this mill controller. Since all you want to do is move the table of the mill this might work for you. It does need an Arduino Mega 2560 as an Arduino Uno does not have sufficient memory space.

The pneumatic one will really eat metal with the carbide burr but be sure to be wearing eye protection and leather gloves as the metal particle as tiny an very sharp. If you get one in your finger it is nearly impossible to see it to be able to remove.

I can't help you with any app for an Android but I use a Raspberry Pi 3B as the computer to drive my Arduino and have the choice of Universal Gcode Sender or bCNC. They both work for sending the code but I can't get the toolpath to show on UGS while bCNC does. The setup feature in UGS makes adjusting the steps for accurate movement a lot easier than doing it by hand.