Member postings for Ronald Morrison

Some of us on the west side of the Atlantic are using 3D printed plastic gears for our change gears. They are cheap as dirt to print and with minimal CAD skills we can create gears with any number of teeth to fit any diameter of shaft. The plastic gears have different wear characteristics than metal gears which may be an advantage but in any case, once the gear is designed and the CAD file saved, one can remake any of the plastic gears for pennies.

There are bearings with the grease hole through the outer race but you don't buy that kind of bearing for the price listed. at least on the western side of the Atlantic. I would expect to have to pay 5 to 10 times that amount for that feature in the bearing as it would be made for a much more demanding application.

I rarely use a left hand tool in my lathe. About the only time I find it necessary is if I need to turn a piece with a smaller diameter in the middle and then I use it to cut toward the tailstock end to clean up the cut. Most other operations work well with the right hand cutters.

Many of the carbide tool are not as sharp as can be had with HSS as the carbide, while harder, is usually more brittle and easily chipped. For light cuts on a small lathe you can use a diamond hand stone to put a sharper edge on them but be careful not to chip them then.

Unless you have a specific need for the fly cutter, skip it and don't lose any sleep over it. It's faster for flattening a big surface but a good endmill will get the job done too.

What will the tooth load be on the gear? If it is low enough like in the geartrain of a lathe where you want the ratio to be correct but the load low a 3D printed gear works pretty well. For power transmission with a higher tooth load then metal would be needed.

it isn't so much that carbide likes high speed it is more that it can work at the higher speeds because it doesn't lose its temper at the higher temperature. The number of flutes matters more with softer material as you can take deeper cuts and that can fill the space between the flutes. You need a way to evacuate the chips faster with the softer material so a single flute or 2 flute mills work better on aluminum than a 4 or 6 flute mill would.

Please, someone with more experience correct me if I am giving grossly wrong info.

In the newest version of Cura you would choose the printer you have in the setup section and it will set the build table size automatically. With a little digging you will be able to find this setting and make changes to the build table size. Do so with care, prints will not come out like you intended if the print head or table hit the end of their movement as the stepper motors will chatter a bit and then assume they are at the right location while they are not.

Corrosion that you can't see may also be the cause. Try cleaning the contacts well before throwing out either battery.

Many years ago I brazed up a new tooth for a motorcycle gearbox where one was broken off. I filed it to rough shape and it worked for the time I had the cycle but the tooth shape wasn't perfect and it made a ticking noise. It was still working when the motorcycle was stolen.

I've used this website to calculate different gear combinations to make specific threads.

Threading calculator

Edited By Ronald Morrison on 23/04/2020 12:04:53

I just checked something on my lathe as I was getting a step when I tried to cut from both ends. I cut one end, turned the stock around and leaving just enough sticking out to run the dial indicator on found the runout and the location of that. I loosened the chuck and started slipping different feeler gauges in where the indicator showed the lowest, then tightening to check the runout. Eventually I got the runout to nearly zero. When I then turned the second end there was no step noticeable. I don't have a 4 jaw for that lathe so this is a poor man's way to compensate.

There are so many things to consider when looking for a mill. Physical size, will it fit into the space available and still have room to work. Table size, will you be able to fit the projects you have in mind onto it with room to secure the project in place. Power, how fast and deep and wide of cuts will you be making. The motor needs to be able to handle that with some to spare. The weight of the machine, how will you get it into the space you plan to have it. Will it be rigid enough to do the job you intend. How will you control it being a CNC mill? Do you have power outlet for that part too? How about the space that control will need? How fat is your wallet? Can you afford new or will used have to do?

Another item to consider is the extruder temperature. Not all PLA works well at the same temperature.

I've occasionally had trouble with a print coming loose from the bed too. I increased the extruder temperature by 5 degrees and the problem seems to be solved. With a glass bed the surface needs to be cleaned with an alcohol solution sometimes too. It's easy to touch it with your hand when you remove a print and transfer just a little skin oil.

i've seen people mention using a mounted stone with their Dremel tool to enlarge the pocket on the table to hold the ball nut.

Stepper motors are listed by size and by the torque they produce. Size matters for the space you have for mounting them. Torque matters as that is what determines whether the motor can turn the load. I've chosen motors that have a little less torque than I wanted for the project but I had sufficient room to offset the motor and use a timing belt. That allowed me to put a 20 tooth pulley on the motor and a 40 tooth pulley on the shaft giving me nearly double the torque (minus a little belt loss) but cuts the maximum speed in half. Estimate the required torque and speed and then choose the motor that fits the space and fits the other requirements.

You may have a leak because the oil you refilled with is too thin or the wrong oil. Worm gears require a specific oil because of the rubbing action.

The suggestions of using an instant gasket type material is a good one but use it very sparingly. Someone used a lot of it in reassembling one of my engines and that gasket material squeezed out everywhere. Externally that wasn't a problem but it wasn't good inside the crankcase.