The TNC slant bed lathe was becoming very popular in the marketplace when I was transferred from grinder engineering. Up until this time, the basic lathe had remained pretty much the same for many years (with a “flat” bed). The big improvement was of course the tilting of the work slide / carriage assembly toward the operator. This allowed the chips generated during machining to drop away into the base, instead of building up around the slide. Most customers purchased the optional chip conveyor which would carry those chips outside the machine and into a separate container, where they could be disposed of easily. Another advantage of tilting the slides was the fact that they were now easier to reach from the operators position; he could change and adjust the various tools without having to reach very far.

The TNC lathe line was offered in many forms; the most popular was a model called the “Combi”. It had a single slide which mounted both a side turret and end turret. The side turret (sometimes called a “round” turret), had slots for six square shank turning tools. It was used mainly for OD turning and profiling. The end turret had six sides (hexagon shaped), each side was machined to accept various boring tools and toolholders. It usually had boring bars that were used for boring and / or threading the workpiece. The combi could cover most workpiece machining configurations . Even though we sold more combis than anything, they could not do everything. If a customer had a long workpiece that required machining on the OD only, we offered a model which had a tailstock and a narrow slide with a side turret. The work could be held on each end, and the side turret was free to machine the OD. This was our “Shaft” model, and it could be had in several bed lengths, depending on what the customer needed.  A variation on the shaft model was the “Universal”; it had a tailstock, and a single slide with both a side and end turret. With the tailstock moved out of the way to the right, it could do side and end machining like the combi; when using the tailstock, the side turret is used to do OD work (although the programmer had to use caution because the end turret could come in contact with the workpiece). Another variation was the “Chucker” model, which was fitted with an end turret only. Basically used on workpieces that required end boring and limited OD machining. The “Four Axis” model had two separate slides, one having the side turret for OD turning, and a second slide equipped with an end turret.

These first TNC’s were offered in three different spindle sizes, 3″, 4-1/2″ and 6″. These numbers referred to the spindle thru hole capacity. As an example, the official machine model might be called a “312 Combi”, which is a combi model with a 3″ capacity spindle, and a 12″ chuck. The “B” designation referred to the model series. These were “B” series machines, the most popular sellers. J&L also offered a family of larger TNC’s which were designated as “C” series and “D” series, equipped for machining larger workpieces. I will review those machines in a later installment.