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Member postings for Ronald Morrison

Here is a list of all the postings Ronald Morrison has made in our forums. Click on a thread name to jump to the thread.

Thread: 7BA Grub Screws with socket (rather than slot)
09/11/2021 12:08:03
Posted by Emgee on 09/11/2021 09:48:05:

Kevin

If the holes are not yet drilled/tapped my choice would be to go with M2.5 grub screws which are readily available in all end forms.

Emgee

If your holes are already drilled/tapped, I suggest you ignore them to drill and tap new ones that will fit the grub screws that are readily available. In the future you will appreciate the convenience of having a common item.

Thread: 'Puter upgrade recommendations
28/07/2021 11:34:17

Add more RAM.

Thread: Stepper motors
25/07/2021 14:18:31
Posted by Andrew Tinsley on 24/07/2021 13:15:51:

Ronald, if you increase the voltage the current will increase and thus make things even worse!

Andrew.

The driver I use allows me to change the amount of current which it regulates. By increasing the voltage I was able to reduce the current and still get the same power to the motor. That reduced the heating of the motor and the heating of the driver chip which was cutting out due to overheating.

24/07/2021 12:08:06

The power of the stepper motors is a product of voltage and amperage while the heating is just amperage. If possible increase the voltage and the amperage requirement will go down.

Thread: Motor malfunction
21/07/2021 13:09:05
Posted by Martyn Stevens on 19/07/2021 01:02:39:

"Thank you all for your comments. Here is a progress report.

I removed the cover to the box on top of the motor. The wiring seemed a bit awkwardly done and the plastic base for the connectors was partly melted. One wire, between a microswitch and a red pushbutton on the outside of the box, was almost rotted thru so I replaced that. I disconnected then reconnected the capacitor and put everything back together. The hesitant start-up has gone, but it don't sound quite right and there is still that "missing" and the intermittent thumping noises.

I was interested in the comments about automatic centrifugal switching of the capacitor, which is a feature of Debrie projectors and there is indeed a very characteristic "click" as the motor runs down.I have fixed one or two of these so may be able to figure out what to do. I am puzzled, however, by some aspects of this. Most older sound projectors, where a fairly constant speed is necessary, use an induction motor with a start/run capacitor, which is always in circuit. My experience of the Debrie and a few other machines that use a start cap and a centrifugal switch is that if the centrifugal switch fails, it very quickly leads to destruction of the cap circuit - afterwards, the motor is still capable of running but will not start on its own. If this is the problem, why is the motor still working?

I will do some pix of the motor and probably put them on my website. One of my problems here is that access to the motor is very restricted and my ability to work in confined spaces is very limited nowadays. Also, like I suspect most hobbyists, I have far to many things/projects to do than I am likely to complete in my lifetime and I really don't need this. Nor did I (or my wife, I suppose) need for her to fall over and break her upper arm, naturally on the dominant side, leaving her severely incapable for a couple of months. I am temporarily a carer and housekeeper. Life? Don't talk to me about life!"

 

I believe that if there are only 2 wires to the capacitor it is a start capacitor and is only in the circuit when the motor is spinning up. If there are 3 wires it may be a combination of start and run capacitors. Since replacing the wire to the capacitor makes it spin up properly, if it only has 2 wires it leads me to think that the "missing and thumping noises" are due to something else.

 

Edited By Ronald Morrison on 21/07/2021 13:10:23

Thread: going carbide on a Myford
10/07/2021 10:40:58

There is a big advantage using carbide inserts in industry. The carbide can withstand higher temps generated with bigger cuts so that if there is sufficient horsepower, deeper cuts and higher feeds cuts down on the time from raw stock to finished product. The carbide is harder so it lasts longer and the inserts can just be changed out without having to stop and sharpen and since they are a standard size the tool doesn't have to be readjusted, just pop in a new insert and you are ready to go. However, being a harder and more brittle material than HSS, they cannot be as sharp or the edge will break off too easily. No problem with enough power but on a lightweight, under powered machine the sharp edge is needed. Carbide inserts can be sharpened to make them cut more like HSS but then much of their advantage is lost as sharpening them takes more time than HSS. With all that in mind, I use a combination of HSS tools and carbide inserts. I have trouble seeing the fine details so a treading insert will get me better threads than a tool that I sharpen. Boring bars with carbide inserts seem to be better for my purposes as I can get them in small enough sizes to use in my small lathe.

Thread: Sieg SX2 or SX2.7
08/07/2021 10:58:33

Unless you will have to miss meals to afford the SX-2.7 or would have trouble getting it to the location where it will be used, get it. You can do small jobs on a bigger mill but cannot do larger jobs on a smaller mill. More mass equals more rigidity too.

Thread: First steps with a Shapeoko router table
11/06/2021 20:34:06

When I first started designing I found CAD to be very difficult. Now it is only quite difficult. I was 3-D printing and only had to enter the design into the slicer and then print. Then I set up my mini-mill with CNC and had to try to learn CAM. I found that to be even more confusing. To keep from wasting precious metal, I will take the extra time to mill the part from wood of which I have a lot, then when I feel the program is doing what I want, making cuts the depth I want, and where I want them, then I will switch to the metal for the actual part.

Thread: Sieg KX3 Y_Axis Skipped Stepper Steps😢
06/05/2021 11:10:00

My Y axis would skip steps. Turned out I was setting the current to the stepper to high and the driver would momentarily overheat and shut down for a few steps. Turned the current down and it didn't have enough power to push the mill through the material. Ahh, power is voltage times amperes. Raised the voltage on the power supply and now it steps just fine. That may not be your problem but is another avenue to explore.

Thread: Drilled Hole Tolerances
24/04/2021 11:58:05

From what I have been reading, a drill is to make a hole. Boring that hole makes it round because a drill may not. A reamer is used to make that round hole accurate. Now you have to decide what is important enough to go through the 3 steps. My farming equipment is usually loose enough in fitment that a drill is sufficient. It doesn't move fast enough that the hole being oversize a little or being slightly out of round will matter in the end. Some exceptions are bearing mounts. That hole needs to be accurately fitted so the bearing will go into the hole with the proper clearance so it doesn't rotate in the hole nor be so tight fit that the bearing breaks during installation.

Thread: Arduino CNC
08/04/2021 11:01:53

Some installations on a Raspberry Pi are simple, some very complex. I don't remember bCNC as being at all difficult. I don't have a touchscreen, just a computer monitor that I affixed to the wall. I like having a (relatively) large screen as my eyesight isn't real good but I can see the buttons with this screen. If you don't have a lot of things on the Raspberry Pi that you need to save, I found that using an install image makes the process painless.Raspberry Pi image

Thread: Looking to learn CAD
19/02/2021 20:41:22
Posted by SillyOldDuffer on 19/02/2021 10:30:33:

I did a thread called Making a start with FreeCAD a couple of years ago, so it should still all work! It's designed to take a beginner step by step through a number of common 3D processes with practical examples and pictures. As FreeCAD is free, there's no cost if you don't like it! FreeCAD parts can be 3D printed.

Though I find FreeCAD useful I'm not banging the drum for it in particular. Though it's a good introduction to 3D and might do all you need, it's also a stepping stone to one of the more advanced products like Alibre etc. Knowing FreeCAD made it a lot easier for me to understand and appreciate Fusion360.

Dave

FreeCAD also contains a decent "path workbench" that produces the toolpath for CNC. At first I found it as confusing as learning CAD drawing but with some practice it got a lot easier. Now I can go from a design, 3D print it if I wish, or just produce the gcode for a CNC mill.

Thread: Arduino CNC
24/01/2021 15:43:29
Posted by John Haine on 24/01/2021 12:47:49:

Right! Not the A4988 then. In my mill power feed I use a DRV8825 on a Pololu carrier board. This is a much more up to date driver with better performance than the 4988 and is happy for the ref voltage to be adjusted without the motor connected -

**LINK**

I've also used the 8834 which is useful for low power motors and low voltages - will run happily on 5V, use two in my Arduinome clock, one for the gravity arm reset and the other for the dial.

If you think GRBL is complicated you should try Mach 3! I got GRBL driving a simple stepper from a UNO very quickly from the serial monitor, the main complication was interfacing to GRBL Controller on my phone via Bluetooth.

GRBL would be interesting for a lathe except that it lacks threading, and a G Code sender adapted for lathe work (as far as I know). A UNO or similar running GRBL is similar in concept to a motion control board, so it ought to be possible to interface say Mach 3 to it if there was a suitable plugin.

As I think more about it I may have been leading you and others astray. I had used a CNC driver board monuted atop my Arduino Uno and had the higher voltage hooked to it for that. Thinking it would be better for the stepper motor driver module I tried to adjust the reference voltage to set the maximum current without the stepper motor hooked up. That was the mistake. That was a year ago and I'm not certain which stepper motor driver I fried. I may have fried both the A4988 and the DRV8825 trying that. I wish the person who wrote the instruction that mentioned not to do that had made it in bold and bright red. One sentence in a page that mentioned not to do that.

24/01/2021 11:59:51

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?

24/01/2021 11:50:59
Posted by John Haine on 24/01/2021 08:06:37:

Any, I'm not sure about the a4988 but on other types of driver you can adjust the pot without the motor connected.

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.

Thread: 3D Resin Printers
16/01/2021 10:09:00

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.

Thread: Arduino CNC
13/01/2021 18:41:05

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.

13/01/2021 12:38:54

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.

 

0529200725.jpg

 

cnc minimill.jpg

z control.jpgsteppers x+y.jpgEdited 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

Thread: Have You considered getting a 3D printer
08/01/2021 00:23:06
Posted by Steve Pavey on 07/01/2021 22:10:55:

I’ve just got an Ender3 v2, which seems to be very good so far - certainly easy to put together and set up. I did manage to drive the nozzle into the bed at one point while levelling it, but fortunately it’s mounted on springs so I got away with it. The first print went much better than I dared to hope for - a bearing holder for the top of the z axis, and I even found a new bearing the correct size to fit it. The only real problem I’ve had so far is loading the filament - I found it a struggle to persuade it to go down the tube for some reason.

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.

Thread: Buying a new lathe and milling machine.
28/12/2020 13:52:33

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.

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