MachinistBlog.com

MachinistBlog.com is 2 years old

By Rob, on January 11th, 2011

No, traffic didn't suddenly drop off. That last point only shows our hits for the first week of January.

January 6th was the second anniversary of MachinistBlog.com. I’m not usually one to brag but I am proud of this achievement. Almost everyone who starts a blog quits within a few months, or even a few days, after they find out how much work it is to keep creating content for one. When I started out I thought it would be easy to write at least one article each day. I was very wrong and quickly decided that one article per week, on the average, would be a more reasonable goal for someone with a family, a full-time job and some other interests. I’m not going to claim that what I write is well-written or very interesting, but for two years now I’ve been regularly adding new content to the web site. But I have had a lot of help and I owe a lot of thanks to these people:

My wife, for putting up with me and my hobbies.

Nate, who has been my copy editor from almost the beginning. He has greatly improved my writing by patiently and gently pointing out my errors. He’s also written some of our most popular and interesting articles even though he’s not a machinist.

Mikey, who really should be the one with a blog. He’s a much more experienced machinist with excellent writing and teaching skills. Mikey has contributed articles, he’s been very supportive and he’s given me some excellent advice.

Earl, Bick, Bogs, Pat, Ralph and Steve (coming soon), who have contributed articles and other material. I owe a lot, and I think we all do, to them and others like them who are willing to share their knowledge and help others learn.

All of you who have visited this web site. I don’t earn any money from MachinistBlog.com. Most of the reward I get is from watching its popularity grow and learning we’ve helped someone or taught them something.

Future Plans and Challenges

It’s been getting harder to meet my goal of writing one new article each week because the things I want to write about lately require more time and preparation.

I hope to create my first YouTube video soon. It’s going to require learning some new skills and overcoming my natural desire to achieve perfection, which often gets in the way of getting things finished.

I’d like to do more photo essays and tutorials. But first I’ve got to buy some lighting equipment because my camera’s flash is too harsh and directional. I think I need an umbrella light but I’ve never used one and I don’t know what to buy. If you can offer me any advice I’d appreciate it.

I’d also like to get the forum going more. I’m not trying to compete with the more established ones but I would like it to have enough users so we can get some discussions going. I chose the forum software we’re using because it’s the only one that integrates completely with WordPress, but I’m a concerned that it might be a little difficult to read and use. Again, I’d appreciate any suggestions or feedback you have.

Simple Coke Can Stirling Engine

By Rob, on January 8th, 2011

This Stirling engine can be built without machine tools or machinist skills. It uses inexpensive and easy-to-find materials and it looks like it is easy to make. I wanted to include it for our many visitors who aren’t machinists but who come here looking for plans for Stirling engines they can build. You can find the instructions for building it on “Scrap to Power”. You’ll also find some other simple Stirling engines you can make, along with some other interesting projects.

CNC Fusion Z-axis Modification

By Rob, on December 29th, 2010

This photo shows the modification I made to my CNC Fusion z-axis mounting bracket so I could adjust my top gib screw with a shortened hex wrench

Here’s a modification I made to the Z-axis ball screw mounting bracket on my Sieg X2 (Harbor Freight) mini-mill. My CNC conversion kit was made by CNC Fusion and their design does not allow you to adjust the top gib screw without removing the column from the base and sliding the head half way off of it, which is necessary to get at a large 10mm bolt that holds it from the inside of the spindle head (along with 2 smaller bolts on the outside). My post about removing the X2′s intermediate gear has some photographs that will show you how much work it takes.

The bracket actually covers up the top two gib screws and there’s not much you can do about the second one except to adjust it properly before you install the ball screw and then hope you never need to adjust it again. To make it accessible you’d have to remove metal near where the ball screw nut is attached and I don’t think you can do that. But there’s nothing to prevent you from making a bigger opening so you can adjust the top gib screw with a shortened 3mm hex wrench. I also made it big enough so I could get a wrench or at least some needle-nose pliers in there to loosen or tighten the lock nut. If I’d been able to wait a week or so I would have eliminated the lock nuts altogether by ordering self-locking ones from LittleMachineShop.com.

I have two mills, which made it possible for me to make this modification. If you don’t have that luxury you might want to consider doing it before you begin converting your mill to CNC. The original opening was about .60 wide and .38-inches deep. It’s now .94-inches wide and .55-inches deep.

I’m not sure, but there may also be another solution and that would be to eliminate the internal bolt by replacing it with more external ones. That would allow you to quickly and easily remove the Z-axis ball screw so you could have full access to all the gib screws. I think CNC Fusion did it the way they did so their customers would not have to drill and tap any holes in the spindle head. Their design avoids that by reusing the holes used by the height adjusting wheel and mechanism. Of course if you used more external bolts you’d have to put them where they wouldn’t interfere with the gears inside the head. You’d also have to make certain they could handle the weight of the head, which I think is about 12 pounds. That’s one advantage the big internal bolt has.

I know this is a boring post for most of you. But I”m hoping it will help others who also have one of these CNC conversions kits.

How I tram my mini-mill

By Rob, on December 22nd, 2010

This is how I tram my mini-mill. I think the method I use is fairly common, although I may use slightly different equipment than others. There are other ways of doing it and some people have strong opinions about which way is best. I’ve included links at the bottom to some interesting discussions I found if you would like to learn more. If you don’t know, tramming is the process of adjusting the mill’s column so the spindle is perpendicular to the table.

By the way, this procedure only trams the X-axis. Unlike most other mills, the mini-mill’s Y-axis is not adjustable, although there are ways of doing it if you’re willing to go to the trouble.

My Equipment

A matched pair of 1-2-3 blocks
A digital dial indicator
The fine-adjustment arm from an inexpensive magnetic base for a dial indicator held in a 5/8-inch cross-drilled piece of drill rod mounted in a collet

I started using the arm from a magnetic base because it was the quickest and easiest way to mount a dial indicator so I could read it from the sides of the mill. It replaced a home-made one that had the DI facing forward (good) and to rear (hard to read).

If your mill vise is big enough you can measure on the top of it with a dial test indicator (DTI) and tram your mill that way. The vise shown in the picture is probably big enough to do that. But the screwless precision vise I often use isn’t, which is why I use the 1-2-3 blocks, a trick I learned from someone else. The blocks will also allow you to tram your mill without removing the vise. I also believe you can get better results by taking your measurements farther apart.

For Best Results

Before you get started you should swing your indicator from one side to the other a few times to make certain you get repeatable measurements and there is no “play” in your setup. You should also center your table under the spindle and make your measurements on its center line and at the same spots each time.

You should know that tramming your mill’s table does not guarantee your vise will hold your work pieces square with the spindle. It should if it was made properly. If it doesn’t you should find a way to fix it, consider getting another one or tram your vise instead of the table. I’m talking about your vise being square with spindle, not with the table. That’s also important, but it’s different topic.

One way to check your vise is to tram your table, mount a long parallel in it, and then measure at the ends of the parallel with your indicator. It should be just as perpendicular to the spindle as your table, or pretty darn close.

It’s Easier with a Digital Dial Indicator

In the past I’ve always trammed my mill using a traditional dial indicator with a needle and dial. Sometimes it would take me just 2 or 3 minutes but other times I’d be scratching my head for 10 or 15 minutes and wondering what the heck I was doing wrong. It was usually because I’d gotten confused reading my “analog” indicator, which is easy is for me because as an amateur machinist I don’t use one very often. So the last time that happened I took my old indicator off and replaced it with the new digital dial indicator I’d bought from Harbor Freight for about $25 (with a 20% off coupon). It instantly put an end to my confusion.

The Procedure

The procedure is simple with a digital indicator. Swing your indicator to one side and zero it. Then swing it to the other side. If the measurement is “negative” then push the column toward that side half the distance shown on the indicator. If your measurement is “positive” then push the column away from that side half the distance shown. Then zero the indicator again and swing it to the other side to check your work. You want to try to get the same distance on each side, although I wouldn’t worry too much if you’re only off a thousandth or so over a good distance (my setup takes measurements about 10-inches apart).

If your indicator has a needle, then use it to find out which side has the shortest distance between the indicator and the table, and then “zero” it or write down the measurement. Then swing it to the other side, calculate the difference in length and push the column toward that side half that distance.

Before you can adjust the column you’ll obviously have to loosen the big nut on the back of it a little. There’s a good chance that the column will move slightly when you tighten it again, so re-check the tram. I’ve found you can minimize that if you loosen the nut just enough to allow you to move the column by gently tapping it with a rubber mallet.

More information

CraftKB: How to tram a Sieg X2 mini mill

The Home Machinist: Tram a mill

Practical Machinist Forum: How to tram a mill for best surface finish / flatness?

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