Tim Siewert LLC- Products for the passionate shooter

My Lathes

By Tim Siewert

Aside from being a master carpenter with almost 40 years experience in the construction industry, I am also a trained machinist, an accomplished welder, and a decent auto mechanic. I first ventured into the machinist trade in the 80s when I took three semesters of machine shop classes at a Vo-Tech in FL. At the time I was working at a custom cabinet & furniture shop. I realized eventually that those two activities, making furniture and machining, interested me the most as far as vocations are concerned. Therefore I decided that someday I wanted my own shop. This is how I want to spend my retired years; making stuff.

In 2012 I bought my first lathe, a ‘60s vintage 12x36 Atlas/Craftsman; for $650. It was a complete machine but it needed some work; mostly upgrades. When I bought the lathe, it had the original motor which was only 1/3 HP, and the only chuck that came with the machine was a type called a “speed chuck”. The cool thing about this lathe was that it came with a milling attachment; something that usually sells for a few hundred dollars by itself and most new lathes don’t even have that option. After using it only a few times I realized that I needed to upgrade the motor and the chuck; the motor was old and not powerful enough; the speed-chuck could not be adequately tightened. After doing a little research I determined that a 1 ½ HP/220V motor would be adequate and ordered a new one. Then after doing some research about lathe chucks I decided to order a new chuck as well instead of trying to find a used one. My reasons for this were #1- I could buy a new chuck for little more than what I would spend for a used one but more importantly #2- a new chuck would be matched to my machine.

Even though I had the three semesters of training and a year+ experience working in three different shops I knew I still had much to learn where machining was concerned. One of things I have learned was #2 in the previous paragraph. Before I bought the motor or the chuck I bought a manual for my machine. The manual I bought, an exact reprint of the original, is actually a 250 page book; it is a wealth of info.

Different lathes have different mounting on the spindle. The Atlas has a 1 ½” x 8 threaded spindle mount (I refer to this lathe as an Atlas because even though it was sold by Sears, the manufacturer was the Atlas machine company of Michigan). Therefore to mount a chuck, a back plate with the correct sized threaded hole is necessary. Then the chuck mounts to the back plate. The back plate is made with a “step” around the threaded hole that engages a correspondingly same sized hole on the back of the chuck. This step is called the “register”. I purchased a new chuck with a matching back plate as a set. Even though the new chuck came with a back plate the register was .060” oversized intentionally. First, I turned the register to .002” oversized on the Atlas, the machine that the chuck is to be used on. Then the chuck is mounted to the back plate by bolts that come with the unit. These bolts go through the chuck from the front and engage threaded holes on the back plate. Once the register is turned then the chuck is “pulled” onto the back plate with the bolts much the same as tightening the lug nuts on a car. This whole process “matches” the chuck to the machine making for the most accurate set-up; and once together with the register .002” oversized, there is no way to take the chuck off of the back-plate; it is permanent. One thing I learned from this was if I had purchased a used chuck then this would have been done on a different machine and the used chuck would not have matched my machine.

Incidentally, I checked the run-out on the spindle before starting the whole mounting process; to insure that the spindle bearings were still good. I determined that the spindle run-out was .0003”; pretty good for a 50 year old machine. To do this I used a dial-indictor on a magnetic base positioned on the bed. Locate the point of the indicator on the top, outside of the spindle, at the base of the threads, and manually turn the shaft by hand and read the indicator.

Threading is the “bread & butter” of lathe work. Almost all new lathes sold today come with a gear box for threading; the Atlas does not. The Atlas utilizes what are referred to as “change gears” for threading. To change to a different thread pitch on a lathe with a gear box one simple “shifts gears” much the same as shifting gears on a car; note: shifting gears on a gear-box lathe is done when the machine IS NOT RUNNING. With the Atlas one has to literally change the gearing set-up on the head-stock. There advantages and disadvantages to both systems. With the gear box it is a matter of seconds to change thread pitch or change feed speed which is also controlled by the setting on the gear-box, but you are limited to the pitches/speeds on the gear box; usually about 48. With the Atlas, any thread pitch can be done from 4 to 112; even half turns (like 17 ½ turns per inch) and metric (some metric threading can be done on a gear-box lathe also). The caveat is to be able to do any pitch within those parameters you must have two complete sets of gears; 13 in all. The reason for this is some pitches like 50 t.p.i. (threads per inch) require duplicate gears in the set-up. 50 t.p.i. is not normally found on a gear-box lathe; normally the settings go from 48 to 52. I purchased another complete gear set for the Atlas because of this. Every pitch set-up is detailed in the manual; one reason why I bought the manual.

In May of ’13 I bought my second lathe; a Jet BDB-1340. This is a standard sized, belt-drive 13x40 lathe. 13x40 is a very common sized lathe; big enough for 95% of lathe work. The Jet is a gear-box lathe. When you refer to a lathe as a “12x36” or “13x40” the first number is the “swing” which is the largest diameter material that can be turned i.e. 12” or 13” material and the second number refers the distance between centers of material that can be turned. The Jet was a “diamond-in-the-rough” when I bought it. It was manufactured in 1980 yet had never been run; it still had the shipping grease on the bed-ways. Also, it was not a complete machine. There was no chuck, no tail-stock, no tool-post, the motor wiring was incomplete, a critical shaft was bent, and most importantly it was missing parts in the head-stock. I paid $800 for it and the guy I bought it from even delivered it to my house and helped me unload it; I guess he really wanted to get rid of it. After doing some initial research before I even bought it, and afterward, I found that every part on my machine is still available.

My first move after I had the Jet in my garage was to get a manual. With the manual I was able to determine what parts for the head-stock I needed to order. Those parts cost a little under $500 and took almost a year to arrive. Because of time constraints I didn’t get around to the task of installing those parts until Dec. of ’14. I then finished wiring the motor. With the help of my good friend Boots, the barrel master, we were able to straighten the bent shaft; this saved me $150 which is what a new one would have cost. This shaft engages the bottom of the carriage and controls the forward/ reverse/on/off switch; really necessary. After searching for almost two years for a used tail-stock, I ordered a new one in March of ‘15. After doing so I realized that, as with the chuck on the Atlas, this was the way to go. When the new tail-stock arrived I determined that it was .052” tall. The distributor rep. told me when I ordered it that this would likely be the case; the exact amount of discrepancy was the only thing in question. As with the chuck on the Atlas, the base of the tail-stock had to be machined to match it to the machine; the tail-stock is in two pieces, a base and the upper part which is the business part. I machined the base on my mill and got it to within .0005”; close enough. To determine how much I had to remove from the base I mounted a shaft between centers and measured the difference in height at each end using a dial indicator mounted on the cross-slide of the carriage. The shaft I used to determine the discrepancy of the tail-stock I machined on the Atlas; I faced, center-drilled, and turned both ends to the same diameter.

With the head-stock complete, shaft straightened, motor wired, and tail-stock installed and matched, my machine is ready to run. The chuck mounting on the Jet is a D1-4. There is no machining required with a D1-4 direct-mount chuck, which I now have. The tool-post was a simple matter of matching the base of the tool-post to the slot on the compound; which is done.

Altogether I have about $2300 invested (the new tail-stock was $660) in my Jet lathe along with about two days of work. As I stated previously this machine is virtually new. A new machine of comparable quality and size would cost $6000 or more. Not only do I now have a new machine at a fraction of the cost but I learned valuable things along the way.

When I was taking classes at the Vo-Tech, the lathe was the first machine I learned to run. Boots has often said that a lathe can “rebuild itself”; what he means by this is that every part of a lathe can be made on a lathe. Running other machines builds on that foundation. Anyone interested in machining either as a hobby or vocation should start by taking classes. Unfortunately, from what I have learned, most schools that offer classes in machining now only have courses geared to CNC work. This is akin to learning carpentry and only knowing how to drive nails with a nail-gun or cut lumber with a power-saw and not knowing how to swing a hammer or use a hand-saw; this may sound trivial but most people do not know how to properly use a hammer or a hand-saw.

I have recently done another upgrade to the Atlas. When I bought the Atlas, I knew that there was considerable play (referred to as “back-lash”) in both the cross-slide and the compound; .025”-.030” in both. While it is possible to run the machine and accomplish things given this condition, it is annoying and tends to mitigate accuracy. Fortunately, there was a simple solution. The screws of both the cross-slide and the compound, which are steel, engage a special bronze nut. Replacing these nuts with new ones has eliminated all the slop, thereby increasing the accuracy of the machine, a $65 solution and simple installation. There are a lot of these older machines out there like my Atlas, and just like the Jet, parts are available for them. My friend Boots has said many times that fewer and fewer people are able to run manual machines yet there are machining tasks that can only be done on manual machines.

All in all, I have $1400 invested in the Atlas including the manual ($47) and a new quick-change tool post* for that machine as well. While not unused/new like the Jet, the Atlas is still in prime condition as evidenced by the minimal run-out on the head-stock and the overall condition of the machine; a comparable new machine would cost over twice what I have invested. Even a new Jet, 9x19 bench lathe, which is about as small as they go, is $2000.

*Quick-change tool posts vary widely in price. The units I have on my lathes are of Chinese make yet are of very good quality. These tool posts were $120 and $130 for the Atlas and Jet respectively. They come as a set with the tool holders; 5 each for various types of lathe tools. Comparable U.S. made sets go for upwards of several hundred dollars yet are only of comparable quality to the import sets. The major difference between the import and U.S. sets is cosmetics and not functionality. Yes it would be nice to be able to afford U.S. made all the time and sometimes U.S. made is competitively priced but I wonder if maybe the reason for the significant discrepancy in prices is due more to gross corporate profit and/or too many levels of distribution opposed to increased worker wages. The tool posts, along with other machining equipment, I purchased directly from an importer who buys directly from the manufacturer. The chucks I bought for both lathes were made in Poland and also of very good quality.

My carpenter business-agent recently asked me how I came to learn machining. He said that he had also wanted to learn the trade for a long time but was intimidated by the intricacy. I told him that much of machining is similar to carpentry in that it involves 1-having the right equipment; 2-knowing how to use that equipment and the capabilities of the equipment; 3-most importantly knowing how to do set-ups; just like carpentry or construction in general, lay-out is always step #1. Machining is also like carpentry in that it almost always involves material removal; therefore knowing what tools to use and how to use them is critical; and good training makes a huge difference.

I am partial to Jet machinery which is made in Taiwan, not communist China. I think Jet machinery is some of the best import machinery available. I also own a Jet floor-model drill-press I purchased in 1985; I have used it a great deal; it is still in prime condition; it is pictured in my second book.

One moral of all of this is while $2300 or $1400 or even the $850 I paid for my mill, a Jet JMD-18, is a significant investment that is not within the realm of many people’s finances, you do not have to invest tens of thousands of dollars to have your own machine shop. The other moral of this story is along the way I have learned much more than I would have if I had just bought new machines. Finally, like the guns I own and all the other tools and everything else tha I own I have all of these things because I wanted them; NOT because I needed them.

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