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Member postings for Hnclad

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

Thread: Would you mesh with this?
15/04/2019 03:55:58

Sam.

Great CAD dwgs. Up front I'll say I know nothing about gear design or theory and my clock making knowledge is not much better. I have made 2 clocks Allan Timmins 8 day long case and Wildings Elegant Skeleton clock and at the moment I am again constructing Timmins long case clock.

Looking at Sam's charts on "pressure angles" I am surprised at how quickly that the angle of the power component is not acting directly in line the tangent of the pitch circle dia. i.e. theta is not zero! in other words there are reaction forces so that only part of the power force is actually driving the gear train, the other reaction force would be acting on the pivots, creating friction and wear. This gets worse as the tooth completes one cycle.

It is making me wonder how accurate do I have to be with my depthing since the pc will not line up for long anyway.

It was always my assumption that cycloidal gears were used because there was a rolling action keeping the pc.in contact for most of the cycle.

Help me out here, and tell me what I am doing wrong.

Thanks David,

Thread: Stepper motor driver connections
18/04/2018 23:09:28

To Joe and everyone else, your enthusiasm and help is much appreciated. I should have made myself clearer in my last post. I said due to the age of my computer it could break down. Last week when I started the computer up to try some of the suggestions I was greeted by an error message. <windowsroot>\system32\hal.dll I phoned my local computer repair shop where the technician told me the problem was most likely a failure of the mother board or the hard drive and the standard charge to determine which was $40. So I have to pay $40 to decide if I want to pay hundreds of dollars for a mother board or hard drive and I would still have an indexer that was over indexing. It was an easy decision. Again i have appreciated your help. David.

18/04/2018 03:37:36

Hi Joe, first let apologize for my delay in replying. We have had a late winter storm here in Ontario that has lasted 4 days. We were12 hours without electricity yesterday. Today Tues. I spend all day reattaching the snow blower to my tractor and moving 8 inches of slush and ice off my driveway so we can go food shopping tomorrow. I have read your lengthy post several times, and I think I have my answer. That is, it is probably the software that is causing the extra indexing problem. I am happy with that assessment. I think considering the age of the computer (15 years!) I use which has a printer parallel port and Windows ME software I should upgrade to a more modern system that has been generously proposed on this forum. My old computer could fail at any time. I have my answers and thank you for your help, I think we should end this thread as everyone else seems to have done. David.

12/04/2018 23:13:36

Hi Joe your explanation of how a stepper motor works was appreciated. I'll try to explain more clearly my last post. First before the indexing program can be used you have to input the indexing reduction. This is in 2 parts, first is the actual dividing head 1:60 the second is the gear belt or timing belt reduction. In my case this was 1:3 (16 teeth to 48 teeth) this part allows you to use the stepper motor to drive the dividing head. It's easier than building a direct drive. The brass worm wheel and hardened screw on the dividing head are manufactured parts as are both of the gear belt and pulleys. I can't see how there can be any fault here. Once that is put into the program you are asked to put in the number of teeth or indexes. I entered 96 teeth and then indexed 96 times, the dividing head rotated a full turn plus a little bit extra, about half a tooth thickness. That is what I meant when I said the although the lowest steps on the driver is 400 and according to you that should only index the dividing head halfway round. It didn't and it actually went half a tooth past the last index, which I assume was an accumulation of a small error on 96 teeth or indexes. I can't explain that any other way.

Hope this helps. David

12/04/2018 20:53:25

Hi seems I was unable to add more text after attaching the photos. To answer one last question from John about the ability of the software to index odd number of index's that would use a partial step. The software has the ability to account for this by adding or reducing the number of steps so that a complete rotation is accurate. Hope that makes sense.

As Joe remarked, all spelling mistakes due to the elderly must be forgiven. I think I can give you a few years Joe, I was born and bred in the steam era, started work in 1959, 5 year engineering apprenticeship and as my email says a H.N.C. lad. Loughborough College of Further Education.

Kind Regards. David.

12/04/2018 20:42:36

dscn0401.jpgp1010004.jpgstep motor info.204122018_0001.jpgHi. Thank you all for your input, I have uploaded some photos to my album, I hope they help. Wildings clock was my second clock, I had constructed Allan Timmins long case clock a few years before. I used a direct indexing plate on the head stock spindle of my Myford ML7 to cut the wheels and pinions. I am familiar with the possibility of a single point cutter causing enough vibration to move the wheel blank. I always use multi tooth cutters from Thornton Successors. I like the direct indexing plate as it offers good locking during machining, Something I worry about with cnc. Also with cnc. you have to make provisions for backlash. That being said it could be handy for the odd weird numbered wheel count not on my index plate. To answer Joe's question on a large wheel blank giving a wrong wheel count. The software program I have provides the number of index's required, no more, nor less, so a larger blank would have thicker teeth since the cutter width is fixed and visa versa for a smaller wheel blank.

I have attached a phot of the connections for the driver & motor using bipolar configuration. There is also a photo of the stepper motor data. I pulled the motor apart, there are 8 coils on what I call the stator. The iron core of each coil has grooves machined in it that seem to match the "teeth" on the rotor. Does this make it a micro stepping motor? John Haines assertion that since the driver's lowest step count is 400 and the normal count 200 steps it would seem that I would have to double the wheel count. That wasn't necessary and I have no explanation for that. After I cut the wheel with a thin tooth I mounted an aluminum disk in the lathe chuck coated in layout blue. Using a scriber in the tool post I marked every index for a 96 tooth main wheel. At the end the final index had over shot the first line. I can only assume that there is some incompatibility between the driver I have and the software which was written for a different driver. step motor info.204122018.jpg

09/04/2018 03:21:12

Hi To answer your question Joe the motor was wired as bipolar series. The phase connection being the terminal ends of the coils were connected to the A+/A- and B+/B-. The centre taps of the coils were connected separately for each pair of coils and insulated. The 18vdc was connected to the appropriate terminals on the driver. That's pretty straight forward. The step/pin8 was connected to pulse+ connection and the dir./pin9 was connected to the dir. connection. Pulse- and Dir.- were connected to pin 20/gnd. There was no 5volt connection. I am creating an album so I can upload photos of this set up and data sheets etc. but please be patient. This is a busy time for me. The weather is perfect for felling dead and dying trees that me and the wife marked last year. After felling they have to be bucked into fire wood lengths, split and piled for drying for next winters fire. It doesn't leave much time for me to get in the workshop or on the computer.

I should explain how I got to this point. 5 years ago I started construction on Wildings Elegant Skeleton Clock, I came across a construction of a cnc. set up for a dividing head, this included the software to run it. The constructor had used a circuit board which he modified, I was interested in the project but was too busy with the clock to start soldering a board. Another amateur clock maker had built the project using a motor and driver from Arc Euro and said it worked fine. I visited their site saw they had a motor and driver on sale and bought them knowing absolutely nothing about stepper motors or drivers. Fools rush in etc.The original constructor used a unipolar motor out of a photo copier so I though I should use a the motor I had in that configuration but quickly realized I couldn't mix 2 power sources. I also realized that 18 to 50 volts was a high voltage for a driver circuit board so it must also run the motor. I was stuck, so since I had already paired the centre taps I would insulate them switch on the 18v. power and see what happened. The motor turned and I was elated. But, when I cut my first wheel/gear the last tooth was very thin and other teeth seemed thinner than they should be. My notes from that time didn't record what settings I used for the steps but I pretty much tried all of them. I never solved the problem and anxious to move on with the clock I put the parts in a box, in corner. Although I moved on I never forgot about the project and when I joined this forum recently I thought I was a good opportunity to see if I could solve it.

Hope this explains things a little better.

Regards David.

06/04/2018 19:45:13

Hi, apologies for not getting back sooner, other chores have been piling up while I have been playing with stepper motors.

The information that you guys have given me was enough for me to wire up the driver/motor with confidence and see if it worked. There are other things I still have to absorb about stepper motors.

The driver and motor are set up my work bench, my index head is on the lathe doing other work, so to answer Joe's question of did I get a 360 rotation with the dip switch set of the 400 steps on the driver, I did. I have a piece of electrical tape on the motor shaft and it made a complete turn but I cannot verify accuracy until my lathe is freed up.

To answer Joe's question, can I index the motor at 10rpm. I cannot, the software doesn't have this feature. There is a "Goldilocks" slider that sets the speed at not too fast and not too slow, in the sweet spot the motor runs smooth and quietly.

I'm going to leave it there for now, it works, I just have to verify the accuracy. I want thank everybody who has shared their time and knowledge helping me to not only get the motor and driver working but also the amount of knowledge I have learned. Thanks a lot.

Kind Regards

Dave

At the moment we have a light snow fall and zero degrees. This is spring in Ontario.

04/04/2018 23:23:32

Hi. I have been away from the computer most of the day, so the latest posts are a lot to absorb.​ I have scanned the data sheet for the motor and driver. If some one can tell me how to attach them to this message I'll upload them.

Joe, thank you for the lengthy explanation it will take me a while to absorb this and see what is relevant to my situation. As you have pointed out I may not need the 5vdc.

Here are the pin numbers to be used from the printer port supplied by the constructor.

Pin 8 to step.

Pin 9 to dir.

Pin 20 to grnd.

John Haines has raised a curious thing that bugged me when I ran the stepper motor as a bipolar motor. When indexing a full turn the indicator needle on my indexer did not return to the starting position. I'll leave it there for now.

Dave

04/04/2018 23:23:32

Hi. I have been away from the computer most of the day, so the latest posts are a lot to absorb.​ I have scanned the data sheet for the motor and driver. If some one can tell me how to attach them to this message I'll upload them.

Joe, thank you for the lengthy explanation it will take me a while to absorb this and see what is relevant to my situation. As you have pointed out I may not need the 5vdc.

Here are the pin numbers to be used from the printer port supplied by the constructor.

Pin 8 to step.

Pin 9 to dir.

Pin 20 to grnd.

John Haines has raised a curious thing that bugged me when I ran the stepper motor as a bipolar motor. When indexing a full turn the indicator needle on my indexer did not return to the starting position. I'll leave it there for now.

Dave

04/04/2018 16:06:38

Hi. To everyone who has participated in this thread, thank you. You have helped me enormously to understand stepper motors. To Neil a special thanks for explaining everything so that even I can understand it. I guess I was fixated on using the motor in a unipolar configuration. I should have uploaded the spec. sheets for the motor and driver at the time I asked the question. It would have saved a lot of time, sorry about that. I have scanned the spec sheets into the computer so I can upload them if it would help anyone. A thanks to Joe for the diagram for wiring the motor in bipolar parallel. In this configuration you have 5vdc supply. Since the driver is connected to a computer via the parallel port, is this necessary as it is getting it's power from the computer?

Thanks to everyone

Dave.

03/04/2018 19:09:15

Thanks to everyone who replied. I have the data sheets for the motor and driver but haven't figured out how to upload them on this site. I'm new here. The motor driver shown by John Haine is exactly what I have, if this driver is only capable of driving bipolar series and parallel motors then it is useless to me as the software I have from the constructor is for a unipolar motor.

The motor data sheet shows that the 8 wire motor can be wired for bipolar series and parallel and unipolar by bringing out the center taps. The motor is 4.5volt+dc. and the centre taps become the power wire in unipolar configuration.

The data sheet for the motor driver is specific that the power supply is between 18 an 50volts+dc. If the driver is compatible with a unipolar stepper motor then I can upload the data sheet, if not then I guess I have a motor driver for sale, cheap.

I did try using the motor as a series wired configuration but the rotary positioning was not accurate???

Thanks Dave.

02/04/2018 23:30:43

Hi, hoping a wizard on this forum can help with connections from and to a stepper motor. I am confused as to which connections to make to a stepper motor to drive an indexing head. The motor and motor driver were bought as a pair from Arc Euro. The stepper motor has 8 wires and has to be wired as a unipolar 4 phase configuration. This part I understand and I have identified the 4 phase wires and connected the 4 center tap wires. These wires then become the power connections. This is a problem.

The motor driver is a common type that I see on many youtube videos. The pulse and dir. connections are made from the printer port of a Windows XP computer. The 4 phase wires A+ A- and B+ B- are clearly identified and the power supply is 18volt dc. connections are easily identified. The centre tap on the motor is supplied with 5volts+ from an old computer dc supply, which seems to me I am mixing 2 dc sources, also where do I connect the -5volt dc wire there is no ground on the driver? Hate to make the 5volt connection and fry the motor or driver.

Appreciate any help. Dave.

Is there any way to upgrade this by using a separate board with a USB interface connected to the motor driver?

Thread: Taylor Hobson engraving spindle
18/11/2017 23:31:21

There is a forum for pantograph engravers, you might try your enquiry there.

Dave

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