Monday 9 July 2018
If you are a hollow form turner, your biggest problem is usually vibration as you try to reach further than you should over your toolrest with your hollowing rig. Advanced Lathe Tools offers one of the sturdiest and most heavy-duty hollowing systems I've used. The company offers hollowing bars and accessories, steady rests, and toolrests for virtually any lathe made, past or present. I had the opportunity to test this entire product line from the toolrests through to the hollowing system including the universal trap, centre steady, laser and banjo substitute.
The Hollowing Bar
The Hollowing Bar is constructed of two pieces of 30mm solid steel bar welded together. The first 305mm of the 1,475mm bar is a single bar so it can hollow through a hole slightly bigger than that diameter if you wish. If you need to extend your reach beyond the 305mm, the double wide bar comes into play. The hollowing bar comes ready to accept 16mm diameter cutter holders and is bushed to accept 12mm diameter tool holders as well. This allows the owner to use virtually any tool holder offered by Advanced Lathe Tools or other manufacturers. There isn't a 'handle' to manoeuvre the hollowing bar as some manufacturers offer but there really isn't need for one. The round bar is easily and comfortably held and easily moved as needed during the hollowing process. It is massive enough that it does take some energy to move but you'd expect that from this heavy-duty tool. I had no trouble performing serious material removal cuts or finesse thin wall cuts with the tool. I tried the hollowing bar using the Munro Hollower II on a green log from a willow (Salix spp.) tree that Hurricane Sandy relocated into my yard. The Munro or other guarded ring cutters work very well with this hollowing bar. Because of its mass, I was able to be fairly aggressive with the bulk removal process. When it was time for the more refined cuts to thin the walls, the laser was installed and the high speed steel cutter was used. The laser, when needed, is easily attached to the hollowing bar with several locations to choose from depending on your depth needs.
The Universal Trap
The Universal Trap is constructed with upper and lower bars fabricated from round steel bars. The trap is 610mm wide and is adjustable to accept any hollowing rig from 20mm to 38mm in thickness. The Nyloc adjusting nut along with a second lock nut keeps the trap bars adjustment secure. I used my lathe banjo to hold the trap in place taking advantage of the provided lock ring to set a repeatable height adjustment.
The Universal Trap has plenty of room for bar movement particularly since there is no 'outrigger' for stabilisation such as is featured on other designs. The hollowing bar's side by side welded bars consume only 63mm of the 610mm so there is plenty of room for movement without repositioning the banjo and trap.
The Banjo Substitute
For a front rest, I used the Advanced Lathe Tools Banjo Substitute. This banjo replacement sits on the lathe bed ways and is fastened in place using a bolt and underways keeper. Intended to be secured in place and moved infrequently, it features a top bar of solid, square stock steel with a multi-position stop pin. The height is easily adjusted and it is also supplied with a lock ring so you can set the desired height then tighten the lock ring. While moving the banjo substitute does require a wrench to loosen and reposition, it isn't a bother. Once I put it in place, I didn't have to move it for the entire hollowing.
I positioned it up close and it was wide enough to accommodate all of the needed lateral position. The base and cross bar easily bore all of the down force from my hollowing.
The Centre Steady
This weldment with three sliding wheel caster arms is a heavy weight. The three-inch diameter UHMW plastic wheels run on industrial bearings so their rotation is smooth and noiseless. At wide open, it appears that steady will accommodate a 610mm diameter piece of wood. I didn't push it this far working with my willow trunk for the test. The arms adjust in and out easily and lock securely. There is a designed in relief to provide for laser light clearance.
Every piece of this hollowing system was well designed and superbly constructed. The fit and finish was flawless and it worked exactly as advertised. Stable, vibration free, and able to reach a long way over the rest. I was impressed with how stable it was regardless of my depth. Truly a winner on all accounts.