Craftsman 109 Lathe - Spindle Adaptor 3/4-16

Using tailstock to start a straight tapping

To make the lathe usable, I will start with the chuck. First I would need to get a chuck that is shorter. It looks like that all the plane back chucks stick out too much because of the extra space taken by the back plate. So the one that would fit well would be the screw mount chucks. I happened to have have read about the 3/4-16 adapter for Taig chucks in Dean's website. So I put in an order to purchase one of 4-jaw chucks from Taig, and getting ready to make the adapter.

Finishing tapping on a vise

To start out, I have cut out a piece of 12L14 round rod. For my weak lathe, it seems that the only steel I can cut at this time is the free machining 12L14. The rod is held in my old 3-jaw chuck, and it is faced and drilled a through hole to about 15/32. Then the hole is tapped with a 1/2-20 tap. The tap was held in a drill chuck from endstock to start the thread straight. It went pretty well initially, but soon it become really hard to turn. Maybe it is because that I don't have a sharp enough tap, but I have to take it out from the lathe to be held on a vise. This is different from what Dean did on his page. Everything looks so easy there. Another thing that I did differently is that I didn't turn the outside down in this step. Part of the reason is because I am not sure if my lathe can turn well with the chuck it has. Well, I am fortunately I didn't, because holding it in a vise will ruin the finish, and it did slip pretty badly. Like all my projects, I always have to go through some rough patches along the road.

Then the piece is thread on the spindle nose and faced. Since the thread on the nose did not go all the way to the register surface, a few threads need to be bored away. I don't have a boring bar, so I have tried to grind a drill bit to be held on tool post as a boring bar. I have tried it on aluminum just to make sure it works. It did. But when I put it on use on steel, it turns out did not cut as well. Maybe I didn't grind the cutting edge well enough. But I ended up just enlarge the hole with the 1/2 drill I have to get it against the register.

3/4-16 Adapter

The picture to the left is the piece mounted on the nose ready to be turned down. A hole is drilled on the back for inserting a bar to remove the adapter if it gets too tight. The front 1/2 in or so is turned down to 3/4 in size. The turning down was so smooth, and it cuts like butter. Turning steel has never felt so good with my mis-aligned chuck. That further confirmed to me that it can work well if I can bring it closer to the nose and the spindle.

As I mentioned earlier, I was able to get the thread cutting of the lathe working. So I got that ready and start threading it. Contrary to Dean's experience, I was able to cut the entire length with the threading indicator mounted. This is the first real thread I am cutting, so I have also bought a 3/4-16 die ready to finish it. I really have no idea how deep it should go, and learnt my share of lessons there. I thought I got it deep enough, and tried it with the die. In the process, I have removed the tool and soon realize that it would not be in the same place when I put it back. Fortunately I have the die ready, and  I would finish the thread with it.

That turned out to be another tough operation I have to drive to the maximum that my little vise can handle. In that process, the surface is destroyed again, which I have to turn down afterward to clear the deep marks. But all in all, I have a cool looking adapter ready to mount my Taig chuck (which I purchased for this modification).

So here is my new chuck, sitting nicely on the lathe ready for the next project.

Craftsman 109 Lathe - Thread Cutting Gears

One reason that drives me to keep the 109 lathe as my project is that it has building setups to for thread cutting. I have got many gears with my original acquisition of the lathe. However, the set is not complete. I have asked the seller about it, but he said that he has never used it.

I looked through the gears that I have. It looks like that I am missing the gears that are on the tumbler assembly. Those gears are available on eBay, but are generally going for $15 to $20 a piece. I have been contemplating about cutting them myself, but I would need to build a milling attachment as well as an indexer. Thread cutting seems to be a rather important part of the projects I have in mind. So I decided to get those gears complete first.

On Dean's webpage (from the same gear cutting link above), it was stated that the 109 lathe uses the same gear as the 618 lathe. So I have been scouting eBay for some time, and found a tumbler assembly. I got it for about $40 (including shipping). But when it arrives, I found to my surprise that they don't fit the tumbler I have. Didn't Dean said so? I went back to read his comments, and it turns out that what he says are that the gears fits (I think he means the change sets).

Fortunately, I think the gears pretty much looked in place, except with a bigger hub size. That should be easy on the lathe. I quickly machined some bushing, and now it goes on like they are made for it.

After some work and additional money out of pocket, my lathe is finally up cutting threads. I have heard that people complaining that the motor is too fast for cutting threads, but mine works just fine for me. I will be using that in my coming projects.

Craftsman 109 Lathe - Chatter

My 109 lathe has serious chatter problem. It is so bad that I could not even turn a small aluminum piece. I have made a few small modifications previously (such as replacing all the jibs with copper ones following Dean's webpage). But it helped little.

The chatter remains, even when the piece was relatively short and hold close to chuck. I have tried may tricks I read on the Internet, slow feeding, deeper cuts, etc. The vibration will still come. The only way I have found that I can turn anything on this lathe is to hold the end of a piece with a center from tailstock.

After playing with it for some time, I finally got a lathe dog so I can turn between centers. Finally I was able to turn a piece and it cuts smoothly. What a wonderful feeling when the cutter just glide through steel like butter.

I have tried to measure the vibration frequency, and it is somewhere around 100 Hz. My lathe at the setting I used most is turning at around 700 RPM. Interesting at one of the pieces I can see the chatter marks that goes about 8 cycles per turn. For 700 RPM and 8 dimples per turn, it turns out at right about 100 Hz. That's what I am seeing.

I have tried to tighten down my tool post, and it did not help. And the disappearance of chatter when turning between centers confirmed that the vibration is probably in the headstock and chuck.

On this lathe I have a standard plain back 3" 3-jaw chuck. It extends quite a bit from the headstock. And it is a big piece of steel. I took the chuck off, cleaned it, and faced the backplate. And it did not help.

Then I realized that the problem is probably with this size of the chuck and the lathe. The chuck is quite heavy, and it sticks out quite a bit. At the same time, the spindle that supports it is relatively small 0.5" steel rod. That is an ideal case for some good oscillation. This chuck does not fit this lathe. I will need a lighter chuck that sits closer to the headstock. It turns out there are many choices.

Why Craftsman 109 Lathe

I happened to have bought the Craftsman 109 lathe more than a year ago. I believe I paid about $140 for it. It comes with gears but not a complete set.

The 109 lathe has a lot of weakness. The most obvious ones are:

• A weak spindle. The spindle is 0.55" diameter. From what I read, it is very easily bent. I suspect that in my playing with the limit of it, I have probably bent mine also.
• No graduated dial.

While contemplating on different options, there are a few choices when it comes to hobbies lathes. Among the most obvious ones are:

• Chinese made 7x series mini lathe,
• Sherline,
• Taig.

Each have its advantage and shortcomings. I have been scanning the local Craigslist hoping to find something interesting. Soon, a HF 7x10 came up at an amazing price of $150. That is a very good price. And I am the first one to respond to the buyer and setup the time to take it.

I thought through that again and again. Yes, at that price the value would be hard to beat. But I don't need two lathes. Yes, I can sell the old one and get my money back probably. But what is the purpose of having a lathe? I am not having a project that needed a lathe to complete. The lathe itself IS the project. Indeed, I have more (easier projects, for beginner at least) to work on on the old 109 lathe than those of the HF lathe. Plus, it is a simple lathe that everything is out in the open. The fact that it is weaker could actually be its strength for me to really learn how to do things properly.

We all know the most important use of a tool is to build other tools. So to build these I have in mind with the challenging weak inaccurate lathe would make things really interesting. These weaknesses are not insurmountable. They just require you to be more creative and do things properly. Take for example the weak spindle. If I am doing something that bents a half inch steel bar unintentionally in my garage, I am probably doing something wrong.

So I have cancelled my appointment with the seller. My project is now playing with the 109 lathe and see where I can bring it up to. I think it will be a fun journey.