Member postings for Ronald Morrison

GRBL looks complicated because it has to be as it controls 3 motors at once, each with its own step rate. Once you have one motor set up with it, it becomes less complicated as you can adjust the other 2 motors similarly. Some of the settings can be ignored while you adjust only the ones you need at the moment.

Thanks to Ady1 for posting a way for experimenting with the A4988 with one stepper motor. Could you see using that to control a rotary table or an indexer? How about just the x axis on a mill or the leadscrew on a lathe? Maybe it would work for the cross slide. Hmm... how about two of them, one on the leadscrew and one on the cross slide to work in a coordinated fashion to precisely fashion odd shapes?

If you connect power to the A4988 without the motor attached it instantly burns out the A4988. It took burning out 3 of them before I found the information on that. It was documented but not real well.

My son bought one. I'm not sure of the brand but he really likes his for making small models. The resin printer can make much finer detail and for the small models he makes it is ideal. He also has an Ender 3 so he could show the difference in the print quality. I think he still uses his Ender 3 for bigger prints where fine detail isn't so critical.

I have both Universal Gcode Sender and bCNC available to use on the Raspberry Pi but use bCNC because it will show the toolpath. UGS would show it too on a more powerful computer.

You may have noticed that I have not completed the power connection to the Raspberry Pi yet but that will be done soon using the buck converter mounted on the board near the power supply to drop the 24 volts to the 5 volts that the Pi needs. My connection that I use now does not supply enough current to the Pi.

I also have a Arduino Mega 2560 set up with Marlin instead of GRBL but I haven't taken the time to do more than verify that it will turn the stepper motors with the commands.

I wanted to try some CNC without a major cost. When I finished I had a functioning but not super accurate CNC mill with the inaccuracy mostly from keeping the acme thread lead screws for the X and Y. My X has about .007" backlash and the Y only at .003". I used timing pulleys and belts for the Y and Z while the X is connected directly to the X leadscrew. I wanted manual control for X and Y retained so the handwheels are left on. That required some compromises but as I learn I am glad to have them. The total cost was about $100 USD. I used an Arduino with a CNC shield and a cheap power supply. I drive it with a Raspberry Pi running bCNC.

Edited By Ronald Morrison on 13/01/2021 12:40:39

Edited By Ronald Morrison on 13/01/2021 12:43:48

Edited By Ronald Morrison on 13/01/2021 12:46:41

I've found it easiest to just remove the nut holding the tube to the feed mechanism and get it started into the tube, the thread the nut back where it belongs. Once started you can just release the feed and push the filament down the tube.

The nylon gears will be quieter and wear slower than metal. They should be plenty strong for anything you will need to do on the mini lathe. If you strip one or manage to break off a tooth, new ones can be 3D printed if you have access to the printer.

Is there a reason why a close fitting piece of Delrin wouldn't make a good way wiper? It wouldn't trap swarf like felt can.

Two thoughts on this question.

1. Do you have CAD experience so you can design a product you would like but can't buy? I use FreeCAD to design and Cura slicer to generate the gcode the 3D printer understands. Both of those programs are free if the budget is of consideration.

2. Have you ever wasted a few hours on Thingiverse to see what other people have designed and made the design freely available. There are practical items and whimsical items and educational items there.

I have designed and printed a few items to repair things around the house. Have you ever tried to search for the plastic end caps on an ironing board foot? I made one of those that had gone missing. I printed change gears for my mini lathe. I made new feet for my folding beach chair so they wouldn't sink into the sand. Whatever you can think of that will fit within the printing envelope can be 3D printed. Now think of the limitations of the material. Not everything that can be 3D printed should be. Got a design in mind but don't want to waste the time and metal only to find out that it won't work or isn't practical? Design and set it up on the printer, start the job and walk away. That printer works the same whether you are watching it or not (unless something goes wrong and the print can't complete but then it stops when it thinks the job is done).

With no power applied, does the lathe turn easily ans smoothly? If not, don't mess with the board, check all bearings, especially those on the motor shaft. Any binding of the bearings will cause the motor to draw too much power and blow fuses.

It's time for you to join the 19th century and move to digital. The fact that your eyesight has changed enough to move you from a vernier tells me that in a few more you won't be able to read the dial caliper either. Voice of experience. Buy a cheap digital caliper and a pack of batteries as the the cheap calipers use batteries more frequently than the more expensive ones. Use that digital caliper for a month, using it's ability to switch between imperial and metric measurements and being able to reset zero to read incremental measurements instead of having to calculate how much stock is left to remove. Use it lots in that month. Then rethink whether you want a dial caliper or not.  By the way, you only need one spare battery, not an entire pack.  My most used digital needs the battery replace about once per year.

Edited By Ronald Morrison on 01/12/2020 10:38:32

I have a cheap carbon fiber digital caliper. I use it all the time but I do note that the accuracy is only 2 digits imperial instead of the 3 digits of the stainless steel one. Quick measurement to get an idea of the size, the carbon fiber framed one works fine. If I need more precision the stainless steel one comes out.

Wild guess about why people want to call Ebay, Fleabay. Being cheap as some are wont to be, they found a "bargain" and without doing any research on the item or the seller, hastily made the purchase. When the item arrived they were upset because it wasn't the same quality as that item from a well known name would have been and thus called it fleabay as a slightly derogatory name.

if you spend enough time on bearing manufacturers websites trying to sort out the terminology the use so you can compare the various bearings between suppliers you will become more confused and frustrated. Unless the bearing is a very special application that requires high precision and high speed operation, just measure the ID, OD, and width and pick a bearing. If the lip seals won't keep the dust out, nothing will. Greasing the bearing won't be of much help as you can't push out all the dust that is in the bearing but simply dilute the grease/dust mix that is in there. Hopefully the location of the bearing will make for easy replacement. Buy 2 or more and store the spares where you can find them.

Wild guess? Speed of operation. Most bearings in agricultural use are slow turning. Other bearings might need better quality as speed is much higher. Now you need to explain where the bearings are used. What kind of agricultural equipment and where on that equipment?

Is there a reason you can't use a Delrin (acetal) nut? They would be much easier to machine that metal and can be melt formed to the acme screw you have for a nut with near zero backlash.

Delrin leadscrew nut

Do a quick search for the word "evanut". Near zero backlash.

FreeCAD

Can you import your Draftsight files to FreeCAD? It's free and open source and allows both 2D and 3D modelling.

You might have to do some talking with the seller and pay shipping since this offer is free shipping to the US only but this set of 5/16" tools might be what you have been looking for.

https://www.ebay.com/itm/8-Piece-TOOL-BIT-SET-HSS-5-16-SQUARE-BY-3-25-LONG/303667134334?hash=item46b3f8bf7e:g:b4IAAOSwQyBfCdF7

Edited By Ronald Morrison on 17/11/2020 12:21:57

Speaking with the seal suppliers without knowing the exact name of the seal can be frustrating. If you can take one of the old seals to a hydraulic specialty shop, just looking at it will likely to get the exact name and they may have them in stock.