The most interesting and useful thing that you will probably find here at the moment is my collection of links about metalworking.
I’m using this site to test designs, ideas and scripts for another web site I’m working on about my interest in metalworking. It will probably be called MetalworkingEnthusiast.com
Rob
It has been more than a year and a half since I bought my 7×12 mini-lathe and I finally decided that I needed to get serious about building or buying a cam operated tailstock lock for it. A lever operated lock is probably one of the most popular modifications for the mini-lathe because it increases your productivity by eliminating the need to find a wrench and turn a nut every time you want to move the tailstock.
Much of my delay has been because of my indecision about which of the various designs floating around the Internet is the best one. So I started sorting through my collection of bookmarks and found that I needed to compare three well-known designs that I could make, plus a kit that I could buy and install easily.
Frank Hoose’s lock is probably very well known because of the popularity of his mini-lathe.com web site. Frank’s lock is based on one by J. W. Early, who may have been the first to design and publish plans for a lever operated lock. Frank does not provide any plans but he has lots of pictures and instructions detailing how it is made, which should make it easy to copy. The mechanism appears to be robust, but a mill is needed to make a 14-degree wedge to provide a flat support surface on the back of the tailstock. You also need to mill a flat spot on the inside front of the tailstock.
It uses a ¾” bolt that has been modified and drilled lengthwise to act as a bushing to support the cam. A hole for the bolt is drilled through the back of the tailstock, the bushing is inserted through the hole and held in place with a nut. The cam is then inserted through the bushing with the actuating lever attached on the back side and the locking plate attached to the front.
The fundamental difference with this design, compared to the others that I am about to discuss, is that a hole is drilled through that back of the tailstock which supports the cam and the forces it generates.
Most of the other designs have a hole in about the same spot so that the operating lever can be located on the back of the lathe. However, in those designs, the cam and the forces it generates are supported by the bottom of the tailstock where the locking nut on the stock lathe is located.
Those other designs seem to be based on Rick Kruger’s tailstock cam lock. Unlike all the other locks I’ve seen, Rick’s locking lever is located on the front of the tailstock. As a result, the lock is very simple to make and it does not require any milling, drilling or any other modifications to the tailstock. There are no plans available for it, but there are enough pictures and instructions on his web pages to replicate his design, although it would be easier if the pictures were a little bigger.
John Moran’s cam lock is based on Rick’s design but he has moved the operating lever to the rear of the lathe by drilling a hole through the tailstock. It is a simple clearance hole and the dimensions are not critical because the cam just passes through it. Again, there are no plans available for John’s design, but his web site has lots of good pictures and detailed instructions for building one. Besides looking like it is easy to make, it is also made out of cheap and easy to obtain materials, mainly a few hardware store bolts and a 1-inch length of 5/8” (approximately) or larger round steel stock, and a small piece of flat 1/8″ steel for a new locking plate.
I am not sure if John’s design requires a mill to construct it. The base of the tailstock where the lock sits is not flat. It has a small slope to it that runs from the back towards the front, which if not addressed could cause the lock to bind and/or the cam to deform or wear unevenly. John flattened the area with a Dremel tool, but at some point after using the lock for awhile he went back and milled it flat.
I’ve read on one of my favorite discussion groups that a penny makes a good spacer when the cutting the cam. Simply put it between the work piece and one of the jaws of your three-jaw chuck. Then cut away what will become the low point of your cam and stop before your bit starts to cut the opposite “high” side. I suspect that you could also create a cam by just filing a flat spot on the shaft and rounding the edges.
If you don’t want to figure out how to build your own cam lock from a bunch of pictures and descriptions then you can buy a kit from Littlemachineshop.com for about $30 (USD, Oct. 2008). Their lock also appears to be based Rick Kruger’s design and according to the instructions all you have to do to install it is to disassemble the old locking mechanism on the tailstock, drill a 1/2″ hole through back of the tailstock with a hand held drill and then reassemble it with the new parts.
Conclusions:
The LMS kit is the easiest way to add a tailstock cam lock to the mini-mill. It appears to be much beefier than the other designs and I think it is likely to be the most durable and trouble-free. It only requires a few hand tools to install and so it may be your only option if you don’t own a mill or at least a drill press.
The Rick Kruger / John Moran designs can probably be built for almost nothing with materials that you may already have in your shop. Even if you had to buy all the materials they would still probably cost less than the LMS lock and you’d have lots of left over material to use for other projects. Building your own lock may also be a good way to develop your skills if you are a novice machinist.
After having studied pictures of the LMS lock, I keep thinking that John and Rick’s designs could be improved upon. The LMS design is obviously much bigger and more robust in almost every way. The instructions say that a half-inch transfer punch is used to mark where to drill through the tailstock, so that means that the cam is about .500 inches in diameter. John’s cam is less than half that, at .215 inches in diameter. As a result his cam won’t be as strong, and because the cam and lock shaft have a much smaller contact area they are likely to wear much quicker. The LMS lock also uses heat treated 4140 steel, while John’s lock uses hardware store bolts made out of low grade of steel. On the other hand, John says his lock has worked well for 2-1/2 years, so maybe it doesn’t really need to be any bigger or stronger.
Even if his lock doesn’t need to be stronger, making some of the parts bigger might make it easier for a novice machinist to build it and also maybe make some tolerances and alignment less critical. However, the bigger you make the base, the more likely that the slope of the tailstock’s base is going to cause problems.
So what am I going to do? I am very tempted to just buy the LMS kit. It would be the easiest way to add a lever operated lock to my lathe, it is reasonably priced, and knowing LMS’ reputation, it will probably work well and never give me any trouble. Even with John’s pictures and descriptions, building his lock is probably going to require some head scratching, some trial and error, and at least a few hours of work.
On the other hand, I would rather spend $30 on tooling that I can’t, or don’t want, to make myself. I’m also intrigued by the idea of maybe improving his lock. So I’m going to either build John’s design, or my own, which would be a combination of his and LMS’. Only I’m going to leave the locking lever at the front of the lathe until I’m sure that I am happy with the design. That’s because drilling a hole through the back of the tailstock would complicate things if I changed my mind and decided later on to buy the LMS lock.
Even though I wasn’t certain how useful or popular a forum would be on my web site, I wanted to have one installed and ready to go just in case.
I choose the Simple Machines Forum (SMF) because at the time it was the only one that I knew of that would integrate with Wordpress. By integrate, I mean that if you registered so you could post a comment on the Wordpress part of the site, then you would automatically be registered to post on the forum also. Likewise, if you registered first on the forum, then you would also be automatically be registered to leave WP comments.
It would have been nice if it would also integrate by sharing the Wordpress menus and theme that I’m using, but that seems to be a tough trick no matter what forum you choose, unless you have some spare time and a very good knowledge of (X)HTML, CSS and PHP.
I also choose SMF because it seemed to be a popular choice, it’s free, and it has a large active community that is trying to improve it. It also didn’t hurt that I could install it with almost no effort using the Fantastico feature that my web host provides.
At first glance, SMF seemed like a good choice. But then I went to post a message where I wanted to include a link to another site. I found that the message posting and editing menu / process is way too complicated, especially for most of the users that this site is likely to attract. There is a help menu, but it took too many clicks to find and get to the help I wanted, and then it wasn’t that good.
I then noticed that my online user profile listed my email address so that it could easily be harvested by the bots operated by spammers, that constantly crawl the web looking for email addresses that they can harvest and abuse. There is an option for users to hide their address, but even though I’ve checked that box, it doesn’t seem to work.
So I went out looking again for other forums that would integrate easily with Wordpress and this time I found this great article about Integrating a Forum with Wordpress. It looks like I have quite a few other options to consider. I have some higher priorities right now, so it won’t happen right away, but you will see the SMF forum go away eventually and something else take its place.
Machine Shop Essentials by Frank Marlow, PE
This is one of the very best and most useful books in my library of machine shop and metalworking books. It clearly and concisely describes almost every machine shop tool and procedure, except for computer-controlled tools (CNC). As a novice machinist, I used it constantly because I kept coming across words, tools, and procedures that I had never heard of. This was the first book about machining that I bought and I highly recommend it to anyone who is a beginner or intermediate machinist. A more experienced machinist may not find it as useful since they will probably already know much of what the book teaches.
This book doesn’t just describe things, it includes step-by-step instructions and useful tips for using many tools and performing many procedures. You can see for yourself by reading these excerpts from the book:
Cutting 60 degree Threads (PDF)
Sharpening Steel Lathe Toolbits (PDF)
Brideport-style Milling Machine Advantages (PDF)
Glossary (PDF)
Machine Shop Essentials is presented in a question and answer format. It is very well organized and profusely illustrated. It is also a fairly large (11×7 inches) book with more than 500 pages.
It is available from numerous sellers for $44.95 (as of December 2007). It is not an inexpensive book, but good books about metalworking tend to be in the $40 - $60 range. In this case, I think it is a fair price for this book. If you buy it directly from the publisher they will ship it to you via USPS Priority mail for $4.60. That’s what I did and it showed up in my mailbox two days later.
If you’re still not sure about the usefulness this book then I suggest you visit Amazon.com, where you can read more excerpts from the book and many customer reviews about it.