Lathe Height
In his book, "Turning Bowls with Richard Raffan", Raffan states,

"It pays to set the center height so it's comfortable for you. You need to be able to see what you're doing without bending, so the best height for the lathe center is about 2" (50mm) above your elbow"

Trestle Legs
Since any wood I used here has the chance of coming in contact with moisture, I used some pressure treated lumber to construct the trestle legs. The trestle feet were constructed from (3) plys of 4 1/2" wide 5/4 PT lumber glued together with polyurethane glue. After milling smooth, the total height of this monolithic slab was 3 3/8". I cut (2) 3 1/4" wide x 7/8" deep dados to lower the legs to the correct height. The dados also gave me a "pocket" in which to secure the lathe's cast iron legs. The feet were constructed such that they were 30" long (10" longer than the lathe's 20" wide cast iron legs) . This increased stance substantially lessens the possibility of cyclic movement during the spinning of a extra heavy, out of round blank. The stretcher was made from 5/4 PT lumber and is 5 1/4" wide. It is reinforced with a 1 1/2" x 3/4" "web" which resides in a dado cut into the underside. This web increases the ability of the stretcher to resist buckling should a lateral load be imposed upon it (for you structurally oriented engineer types, think of it as a "T" Section). This feature will come in mighty handy should I install a mobility feature to this lathe. But that is a project for the future.

The stretcher was joined to the legs via a half lap, and secured with lag screws. I removed the supplied levelers from the base of cast iron legs. This left me with a 5/16" tapped hole. Using a forstner bit, I cut a counter bore into the bottom of the trestle feet to receive a 5/16" T-nut. I then cut (4) 3 1/2" long sections of all thread rod, and used (2) jam nuts secured with Lock Tite to make attachment hardware. After all that work, the final assembly went together quite easily.

Ballast Box
Now that the trestle legs were in place, I could move onto the ballast box. Like I have mentioned above, this cast iron lathe is not a light weight. At 435 lbs, it's more than heavy enough to handle every day blanks. However, having access to some larger logs, I wanted to be able to turn some big bowls. After reading up on the benefits of adding weight, I decided to add a ballast box to the list of accessories I wanted to make for this lathe.

Let's talk about safety:
Referring again to the book, "Turning Bowls with Richard Raffan", Raffan has the following chart:

He goes on to state that, "the speed for rough turning blanks should be approximately half those shown". I try to follow these rules as much as physically possible. I even went as far as to post a copy of this chart on the wall above my work bench.

I'm not saying this to discourage you from adding weight to your own lathe. Just read your manual and be aware of your lathe's capacities. Much like having an SUV does not make you invulnerable to an icy road, adding weight does not magically bestow a lathe with the ability to spin a huge out of round blank at 2300 rpm! Mostly any lathe around will jump around like a bucking bronco if you try that! Like Clint Eastwood said in the Magnum Force, "A mans got to know his (or his machines) limitations." Large blanks need to revolve at a lower RPM. Take it from someone who once tried to spin a 18 lb, out of round blank on his JWL1236. It is not a pleasant experience!

With these guidelines in the back of my mind, I went ahead and drew up the plans for my ballast box.

The Design
This box was sized so that it would not interfere with the swiveling tool basket, but still comfortably sit inside the space between the lathe's cast iron feet. Another requirement was that it be able to hold at least 300 lbs of sand. Each leg features a cast bracket sized to receive a 2 x 4. The manual suggests cutting some plywood panel and securing them to the top of the 2x4s to act as a shelf. You can then lay sand bags on top of them for ballast. While this suggestion does have it merits, I wanted to be able to contain the sand bags better. The ballast box I designed measured 15 3/8" high x 13 1/4" wide x 47 7/8 long. I was somewhat restricted when it came to the height of the box by the fact that I had to make it so I could remove the lid easily. This box is to be installed in some pretty tight quarters.

Using the cast iron leg layout I drew up for use in working on the trestle legs, I designed a ballast box to hold (6) 50lb bags of sand. The material of construction was 3/4" plywood. Rather than belabor the construction with a lot of fancy joinery, I opted for using dados, and rabbit joints. The 3/4" plywood base was held in place by a 3/4" wide x 3/8" deep dado in all sides. Since this box is 47 7/8" wide, I reinforced underneath the panel with a 1" x 1" x 12" long cleats on each side. My one concession to "vanity" was using oak plywood, and trimming the lid panel with cypress.

Rather than sitting on top of the 2 x 4s when they are inserted into the brackets, the box is sized to fit between them . Using this approach, I was able to lower the bottom of the box closer to the floor, and thus make the box taller. This increases the amount of sand the box could comfortably hold. I beveled the tops of the 2 x 4s in an effort to minimize the amount of debris that would collect on an otherwise flat surface.

As shown above, I installed 1 1/2" x 3/4" Cypress cleats across the front and back of the box. These spread the load out along the stretchers and made it easier when it came time to install the box. The ballast box was secured to the 2 x 4s by (6) 1/2" bolts (3 each side). As with the stretchers, I rounded over the tops of the cleats to help minimize the amount of chips that would collect there.

The lid was made from 3/4" plywood, trimmed with cypress. I cut a 3/8" thick x 3/8" wide tongue along all sides, and cut a matching mortise in the cypress rails and stiles. The lid assembly features a 3/8" deep x 3/4" wide rabbit along it's bottom. This rabbit is sized so that the lid will seat itself firmly onto of the box. Due to space constraints, using a hinge was out of the question. There was just no room for the lid to swing open. So I opted for a lid that could be lifted out. A line of weather stripping was run along the inside of the lid to help to cushion any contact between the lid and the box.

After I had completed the assembly, but before I installed in onto the lathe, I gave the ballast box a couple of coats of Watco's Tung Oil Finish. After I installed the box onto the lathe, I gave the assembly a coat of Johnson's past wax.

Trial Run
All of these improvements would be worth nothing if they didn't accomplish the intended task. In order to test them out, I selected a large maple log from my wood pile. From this I was able to obtain a 15 3/4" diameter x 6" thick blank (approx.). Below you can see it installed on the lathe's faceplate.

Since this was my first attempt at turning anything this large, it was with no little anxiety that I started the lathe up. I let Raffan's chart guide me in adjusting the lathe's speed. After some adjustments, I was able to settle on a comfortable speed for a rough blank of this size. As you can see below, that was roughly 600 rpm.

My first impression on using the lathe with the increased height and ballast box was comfort. Since I was standing up straight, I was able to work longer without my back starting to ache. I also noticed that my "tool posture" (for lack of a better phrase) was better, and I was getting more consistent curls. The benefit of the increased weight became more apparent when I started to ramp up the RPMs. The sand dampened any wayward vibration, and actually seemed to make the lathe run smoother. The increased stance of the trestle legs also went a long ways towards increasing the stability of the lathe. Trying to compare the experience to turning on my smaller Jet JWL-1236 was like night and day. So I would have to conclude that the installation was a success.

Final Impressions:
I feel that these two upgrades took an already great machine and "kicked it up" a couple of notches. If you're willing to take the time to look into adding these to your lathe, you won't be sorry.

Thanks for viewing.

Dominic

 

—DG