Dear Friends,
This week began on Sunday night. My dear friend and expert machinist/tool & die maker Matthew Skidmore (henceforth to be referred to as Skiddy) asked if he could come over and take a look at the mill. I was thrilled for the opportunity. I gave my loving wife a peck at 5pm saying "don't worry, this won't take long" to which she replied "I'll see you in the morning." Turned out she was right.
Skiddy and I go back about 5 years when we were introduced by my best friend Evan. At various times, I have had the pleasure of watching Skiddy work in his element, surrounded by million dollar machines, cutting parts that will eventually go into space. One night we spent 9 hours working in his shop on a critical component that would allow the electric motorcycle I was building to work with an old Suzuki tc90 frame and swing arm. Another time he explained to me how it is possible for us humans to make something that is perfectly flat without advanced machines. It can be done, in fact, by three stones. To this day we don't have a better way of making a perfectly flat surface other than rubbing three stones across each other for a very long time.
All this to say, my wife knows me well... I didn't get home until 2:30 in the morning.
We spent the whole night working on the basics of machining, how to use the software that the mill has built in, and how to define a work offset (which for those that are curious is the "point" in three dimensions from which the program references its travel distances). He also helped to show me how to install tools into the tool holders and create their offsets (so that the machine knows where the tip of the tool is and can automatically adjust the programming to compensate for its length). During this time we began to realize just how many tools I was missing that are standards for machinists (and frankly just normal human beings). He said that he had many extras of the various tools, and would be willing to give me them so I didn't need to buy them. Skiddy is a very generous person.
After I got home that morning, I slept for about 5 hours and then got up to get rolling at work. Meryle let me know when I arrived that we had a bit of a problem. We needed 50 bars right away and probably 70 bars by Wednesday to get through the orders. Normally, making bars by hand takes about 3 hours to make 20. That would mean that we would lose a person for at least a day or likely two just to make the bars we needed. I, with newfound confidence, said that I could whip up a jig to hold the bars and have it drill the holes in about a half and hour... That turned out not to be true.
Now in my defense, had everything gone as I had planned, it would have taken no more than an hour. My idea was to use the same jig I had designed for our manual bar making, cut out of wood on our xcarve, and then put into the machine. I was pretty sure I could figure out how to use the software that Skiddy had shown me the night before to do a simple drilling operation, and a half an hour later (or probably about that long) I had done precisely that. It may have been closer to an hour and a half, but this is my story.
Once I had everything in place, I was able to grab some of the bars that Trevor had cut to length and width and put them in the machine. After a few test runs, it became clear that something was wrong. The holes were not in the right spot at all. I checked the programming, and it was correct. All this time I had been sending Skiddy some pictures and such, and I sent him another exasperated plea to help me figure out why this wasn't working (it would certainly not be the last time).
He explained that my setup wasn't rigid enough. Now looking back, knowing what I know now about what he was saying I understand it much more. However, in that moment I didn't have much of an idea of what the issue was. When you make bars manually there is a certain process when you are drilling the bars that is very tactile. You press down with a certain amount of force to get the bit to bit in, and then you can adjust your force dynamically to adapt as you are cutting to ensure it comes out right. You can also use your hands to slightly reposition the bar as you come down with the bit to make sure the hole is in the center. With this machine, none of that is the case. It has an enormous amount of power it applies, and is intentionally extremely rigid which allows for precision. So my wood holder would literally be buckled under its force.
By the end of Monday I was pretty dejected...
We desperately needed the bars due to an influx of orders that used the journals, and had I spent the day making them manually rather than messing with the machine, we would have had maybe the 50 we needed. Instead I had pushed so hard on trying to get this to work, that I had wasted the day. In hindsight, that moment was pretty important as it really hit home to me the key thing with machining. You can never assume its just going to work.
I went home and had dinner, and then Skiddy asked if he could come back to the workshop again that night and help me. I of course said yes, and it was going to work out well anyway because I needed to have a meeting with some people in Australia at 8pm. My meeting got over just as he was unloading his car. I went to help him, and realized that he had brought tons of stuff. Everything from measuring tools, to raw material, to cutting tools and much more he just gave to me. Skiddy is a very generous person.
We began to set to work on crafting a proper jig to hold the bars and the material. Skiddy walked me through a lot more in the way of how to properly use the measuring tools, and what are the various advantages and disadvantages of the bits. We also covered the basics of GCode, which is the language that drives the machine and how its edited. He also explained to me "spot drilling" which was critically missing from my prior operation. That is where you take a very rigid drill (designed for this purpose) to put a small pilot hole where you want to actually drill out. This tool allows for a very precise placement of the drill holes and then the drill bit can follow that initial spot for its alignment.
We also experimented with the rigid tapping process this machine is capable of doing. That took quite awhile and it wasn't really until about 1am that we began to cut metal. Using the limited endmills I had, Skiddy helped create a strong metal base which was held in my machinists vise in the mill. From there we were able to drill and ream small holes for press fit locating pins (which you use to ensure the metal you are cutting is in the same spot over and over). We created some makeshift work holding "fingers" that press the metal stock in place during the operation. After all this, it was about 4am. Skiddy could have done it much faster but he was showing and explaining all the concepts to me as we went along. From 4am to 7am he was working hard to write various programs to properly cut the bars out of the stock once they had been drilled and tapped.
Unfortunately, we got to a point where he had to leave and go to his job. So I took over. With a significant expansion of my knowledge (for this limited example) I felt confident that I could write the program to do the job. So I spent the next few hours running and testing things only to snap the last of my endmills. I went to Harbor Freight about 35 minutes away to get more (since they were the only ones that had them locally), but they only sold them as a kit and there were only two (technically one 2 flute, and one 4 flute) endmills in the correct size.
After coming back, I went back to work and promptly snapped those endmills as well, and thus had to rewrite the code to work with alternatively sized endmills. By this point I was getting the hang of the coding, and all the while I was confident I could get bars made. I had also been awake for 30+ hours at that point, so that may have been part of my issue.
In the end, Tuesday finished out with exactly 0 bars being made... So now our problem has gone from bad to much worse.
I did sleep that night though, and woke up with some new ideas on how to get it working. We also had 2 new carbide (expensive, but much better than the High Speed Steel we had been using) that were arriving that morning. When they came in I was able to test my code and it worked! Victory was mine... Until I broke the endmills...again...
So by now I'm sure you are all wondering why I keep breaking the endmills. Let me tell you, by that point (and much earlier) I was also wondering that same thing. Before I didn't understand how to calculate the speeds (the spindle spinning speed) or the feeds (how fast that spindle moves across the material) really at all, and was just trying to use some guesswork to make it happen. But by Wednesday morning I had actually taken the time to learn how to use the formulas to calculate it so when the endmills broke I pretty much lost my mind.
Skiddy and I went over my calculations and while they were technically correct, he recommended alternative ones as well as a smaller depth of cut (how deep you cut into the material with each pass). I took that time to polish up the code to make it as perfect as could be and ordered more endmills.
So we ended Wednesday with exactly 4 bars made... So now the problem has gone from worse, to even worse still.
That brings us to today...
I have 7 endmills coming today from various sources and once they arrive (and it sounds like some just did as I'm writing this) I can finally run this program properly. So I'm going to finish off this email saying that for those who have been waiting, thank you for your patience. Your order should go out either today or tomorrow as I get this thing cranking.
I'll let you guys know next week in the podcast (which should be back on Tuesday) how it went from here.
Now I'm off to get this party started.
Stay tuned for more letters on Thursdays in the coming weeks and be sure to go subscribe to our YouTube channel. If you like and watch the videos it helps us get promoted more by the algorithm to people who may never have heard of us.
Ever your servant,
Colin Murdy
CEO/Owner
Murdy Creative Co.
Cell: 414-434-9001
MurdyCreative.Co
