Wednesday, 30 August 2017

DIY Ebike Part 1 - episode 159

A change of pace this episode. For many years i wanted to build an electric vehicle. Several things stopped me at the time, the biggest of these being money. I really wanted to build an electric car but the best I could hope for was an electric bicycle. I made a couple of attempts when I was younger but never quite managed to do it.
Fast forward to an interview with Bill Griggs of CNC Router Tip Podcast a few months ago and a question he asked about what I would like to do if I could. Eventually I remembered the Electric vehicle I never managed to build.
Check out the interview here 

Yes Bill this is all your fault. :-)

My budget for the build is very small but I already have some batteries and after searching around I found some kit options. I could have bought an electric hub but that isn't my style, (or lack of).
I also want to explore the option of rear wheel vs Mid drive and an electric hub won't work for this. It seems that Mid drive is the way of the future so once I have it running in this configuration I will look to changing to Mid drive and see what the difference is.

Click to watch video

The Kit
I ended up buying a 250w kit because 300w is the maximum allowed for an electric bike in New Zealand. The kit is very cheap compared to others drive systems available and made it worth tasking the risk.
Electric bike kit I used

This video is the unboxing of the kit and showing what comes with it. I was quite surprised with some of the little extras that came with it which was very welcome and made the install easier. 

I hope you find it interesting despite that there is no CNC in this video but I wanted to share the build process. There will be a little CNC in this project and will be using a new toolpath technique I haven't tried before so that will be something to look forward to.

Will it work?
Join me for the next thrilling installment.


Tuesday, 22 August 2017

Recover X&Y using Magic Offsets - episode 158

After my last video it was noted that I had left out 1 option to recover from a power outage and recover my X,Y,Z original positon. I had not covered this option for a couple of reasons. 
What was the method?
Using the offset between Machine coordinates and Working coordinates you can recover your position. It has long been used by machinists who have homing switches on their machines to restart the next day and take up from where they left off. Brilliant! I hear you say, but this method has always had a fatal flaw and to the best of my knowledge no cure. The offset is not saved unless the PC is shutdown correctly. If the power goes off in mid cut the offset values are lost. 
Jerry Rutherford from "askjerry"  Youtube channel, did a video response to my last video and explained the offset priciple and how it can recover position if the machine is shut down correctly.
He also showed that if it is not shutdown properly how this position is lost. Jerry is using LinuxCNC but the principle of operation is the same.

I did a bit more research into offsets to find a method to save them and much to my surprise there is a very simple way to do this, right under my nose. I gave it some testing and found that it works very well in both UCCNC and Mach3
I don't know if this is not well known but I haven't heard anyone mention this feature and given how with the push of a button you could save your work from ruin I'm surprised I haven't come across it before.

Click to watch Video

 Homing switches

This method really suits those who have homing switches installed on their machines. Combine automatic homing with the Offset save feature and you can have a fast accurate method to reset your cutter back to your work.

 The accuracy of such a setup is only as good as the accuracy of the homing switches. If you cannot get repeatible results then you need to look at your homing switch setup.

Manual Homing

While the video demonstrates that it works and works well in reality it will probably only get used in large jobs simply because of basic human nature. 

My personal opinion

In the past expressed the opinion that limit and homing switches are not "needed".
I stand by that opinion however, this is the first time I have seen a feature that adding these switches to my machine would give me that I consider worth having.
While I will not be rushing out to install them at this time I will think about adding them at a later date.
Please do not think that I am anti limit switch because I'm not. Up until now I haven't seen anything that they will do for me that interests. That isn't to say that I wouldn't use that if I had them. Most likely I would probably enjoy having them but there is a difference between Need and Want.

Thanks Jerry for making this video and testing other options.

Here is Jerrys video explaining how the offsets work and he demonstrates how to do it using a leadscrew machine. His Frankenlab series is well worth watching and don't forget to check out the Awesome laser he has for his machine. 

 Jerrys YouTube Channel

Check out his video below.

Click to Watch Video

Final thought
I don't know if there is an option to do this or not but i would like to see offsets automatically saved everytime your X,Y or Z working coordinate is changed with the zero button. This will then ensure that a recovery is always an option if you have homing switches installed. Maybe a macro will do this, but I will have to leave this to people much smarter than myself. 

Thank you for taking the time to read this and I will catch you next time.


Wednesday, 9 August 2017

How to find XYZ - episode 157

Loosing position while machining a project can happen for a variety of reasons. sometimes the work is damaged beyond repair and sometimes all you need to do is reset your cutter back to the origin point and resume cutting. While the destruction of a piece of work is a blow that we will all eventually suffer the 2nd senario can be the more frustrating. a perfectly recoverable piece of work if only there was a way to find the origin point and continue from where it left off. 
This video highlights 4 ways of resetting a cutter to the table if you loose position. The difficulty of the recovery process will depend on whether you take the extra minute and plan ahead when you create your files or you decide it will never happen to you and take the chance.

Click to watch video

Ultimately accuracy of the reset cutter will depend on what method you use to reset and if you are doing it manually how much time you invest in getting it right. When it comes to ease, speed and accuracy you can't go past using electronic methods such as the tripple edge finder. The next best option is the hole method demonstrated in the video. After that it gets much harder and accuracy will vary. I found the slot method or setting the cutter particulary frustrating because I filled in the X coordinates into the Y DRO in my controller software and had to restart. It is not dificult but if you aren't paying attention you can easily make a mistake.

Homing switches
Since I do not have homing switches on my machines and have never used a machine with limit switches I cannot comment on if they are useful for resetting or not. If someone can point to a video demonstration of the recovery process then I will update this page and put a link to the video for those interested.

This video is a follow on from my previous video on the subject of stopping and restarting Mach3

Stop and restart Mach3 - CNCnutz Episode 119

 At the time of making this video I did not have UCCNC but both softwares are very similar in operation. If you are using an automated spindle make sure you have the Estop switch at hand in case the spindle does not start turning when it restarts the cut. In hindsight and on both controller softwares I would manually start the spindle just to be on the safe side. Personally I am still getting used to an automatic spindle and I can honestly say I am still can't get used to it. I do like the auto stop feature though.

Tripple Edge finder
This product designed and  made in the USA by Bill Griggs is a versitile piece of kit.
It probably has far more uses than most people realize and if you are looking for a product to reset your X,Y & Z position you would be hard pressed to find anything better.
Check it out

 If you are interested in this product check out his website and the various tutorial videos he has on installing it into Mach3 and using it.

The 2017 Screenset for UCNCN from   has built in centre finding and auto Zero that should work well with this product. I do intend to test this out myself in the near future.

2017 Screenset Probing video

If anyone has additional information regarding the Triple edge finder and UCCNC please let me know and I will update this.

As usual your thoughts and comments are always welcome.
Thank you for taking the time to read this and until next time.