Thread: Holz Her RKS 2140S Ring circular saw

Good on ya Gerhard for that report. Most interesting! Might keep a look out for one of those in future!

Damien

Hi Damien,

Thank you very much! Yes, great machine, isn't it? When you type "holz her ringkreissäge" in google, you may still see some traces of the eBay auction in question, since it wasn't so long ago. There is on average one such machine on sale every 8 month on eBay Germany or Austria. I got mine from Austria and paid 895 Euro's for it (excl. P&P) almost 3 years ago, in a condition as good as new, including box, but alas without manual. The rings come with either 12 or 16 TCT-teeth. With just 2500 rpm (=no load speed; less than 2000 nominal is not recommended since slipping occurs very soon after that) more teeth than that would probably obstruct proper dispensing of all the sawdust.

Spares are no longer available, not even from Festo's bought up Holz Her inventories from distributors around Europe. The drive cone, the guide wheels, rip fences, extended Flex angle grinder drive axles, they're all gone now. So any owner treasures his machine and makes sure to get maximum life expenctancy out of it.

My particular auction ended at 3 AM (i set the alarmclock), it must have been a particularly sleepless craftsman to enter an auction at such time in the morning. A ship builder who also watched and wanted it, bugged me for weeks afterwards, trying to buy it from me, for he didn't set his alarm and slept through the moment. I later managed to buy some brand new saw rings from a German tool wholesaler (on eBay too), clearing old stock. Some of those went for just 15 Euro's a piece, that must have hurt (RRP was 80 to 120). The machine has been sitting in its box for almost two years now, when i have proper display space it is time to put up all the 700 machines i have for show. A little museum is something i wanted for a long time, it seems a great pensioner's hobby later on.

When i inspected the machine some months ago, the magnesium alloy parts had accumulated some oxidation, in spite of silical gel bags in the box. There's no way to get rid of that up to bare virgin magnesium in a totally invisible way, i think it's best to rub some very fine finishing paper over it (until the white hydroxide is gone and the black oxide appears) and then finish with a matching silvery paint (Revell of Humbrol modeller's paint is ideal for that, sinde the choice is huge and the finish can be made very fine and clean with it).

The added PDF exploded view is from the original L2806/8SC power unit, so Flex can come up with motor and housing parts if needed. Shown is the 2500 Watt version. This type itself is no longer available (though the parts are) but Flex still makes the 3000 Watt motor; their core drill BED303 is fitted with it.

Greetings from Amsterdam and all the best!

Gerhard

Guys,
These were great articles!! I have one of the Holz-Her RKS saws. Actually I have three.
I have the big one in your articles (1) and I have two of the older original ones.
Have had all three for years. I dont use them much anymore, but the big one is a beast and never let me down.
I don't know much about the original (old) ones, but they are as far as I can tell from the 1960's. Made in silver-grey pot metal. And really the scarfiest looking things I have ever used. But damn they ran hard and good!! Blades about 40mm smaller in diameter of the big one that you have in your pictures.

The articles are great and now to my second point...
Gerhard, if you are interrested in one of the old ones for your museum/collection, let me know!!

John in Berlin, Germany

Gerhard, what an amazing machine!
I sort of get the friction drive concept, but I really can't get my head around the concept of a blade being able to plunge to a greater depth than 35-40% of it's diameter. If not an axle, what actually holds the blade perpendicular and parallel to the body?

I'm also terrified by the third picture showing a completely unguarded blade on the LHS just a couple of cm. below the auxiliary hand grip! As the saw plunges into the timber, I assume your hand would also plunge until it was alongside the revolving blade! I see what appears to be a hinged, perforated guard, but this seems to be guarding the workpiece rather than the operator's left hand.

What a legacy you will leave to the world, Gerhard. The post-war economic boom in Germany lead to an explosion of innovation in tool manufacture, with many (most even) manufacturers not surviving into the new century. This era of quality and creativity stands in stark contrast to the imitation, cloning and "badge engineering" of large manufacturers in the Far East of the last 10 years or so.

Future generations of mechanical engineers will marvel at the generous (even wasteful) use of copper in the motor windings and the exotic alloy castings and will gasp in amazement that the tools were designed to have a lifetime of more than 3 or 4 of years! Of course, none of them will believe that the tools were actually designed to be repaired with new bearings, armatures etc. instead of being recycled for a new model every couple of years.

Originally Posted by gerhard

Hi all,

i collect electric tools, and i thought i might introduce you to a special circular saw version, that i know from no other brand than Holz Her Germany. The woodworking machines of Karl M. Reich are specialist machines for furniture factories, timber mills, forestry and wood products like plate materials and veneered woods. They are heavy, large capacity, robust and expensive. The name was chosen in 1925 for Reich's range of electric hand tools, based on the German roof constructor's cry "holz her!" ("wood over here") to colleagues on the ground, to have them reach up new timber.

There are regular circular saws with a certain saw depth and when more is required, vertically mounted chain saw blades mounted on circular saw type base plates are the usual alternative. The saw ring was an attempt to achieve maximum depth from a rotary system by getting rid of the arbor in the middle, and drive the ring from the upper quadrant. This drive is of a friction type, by means of a fabric reinforced resin cone, and the saw ring is clamped between rollers and bearings to absorb thrust and keep exact lateral guidance and secure axial grip. The ring is also held in place by a circular groove on one side and flanged rollers on the matching machine side, matching this groove. There is a round plate in the center, around which the ring revolves. This plate is meant as a stabilizer, with unpredictable warping forces in the wood, coming free as soon as it is parted, the ring might otherwise easily be pushed out of the proper saw line, making a decent cut impossible. The plate is fixed and does not revolve, the little hole in the middel just shows where the arbor/axle would normally have been, if this were a regular sidewinder. There is also a regular rip fence behind the ring, which is seen unscrewed from the machine in the pics beneath.

One of the largest sidewinders is the Hitachi C13U, which manages about 130 mms saw depth (approx. 5.1 "). This ring saw manages 185 mms (approx. 7.3 "), because the ring with its 305 mms diameter (12") can dive into for the material with more than half its heigth, for the drive system is concentrated within the upper quarter. Power was of course an issue; when this machine was designed in 1989, there were few brush motors around stronger than 2300 Watts. The introduction of the Ackermann und Schmitt L2808SC angle grinder with 2500 Watts was a solution. This motor was cranked up to 2800 Watts soon after that and Reich chose it as a power source. Electronics were added, for soft start was really needed with such a surge. With this device added, this is a 3000 Watts drive system with Amp measuring and overload control. There is a little window in the saw's hind grip with coloured LED's underneath, showing normal use or upcoming or actual overload.The dark grey motor unit built lengthwise along the side (just like in a worm drive) has indeed the recognisable shape of a grinder motor, with an electronics box at the rear instead of a handle.

The pics below are from eBay and show a used machine, recently going for about 700 Euro's (the price when new was about 1600). Mine is stored and in demo-shape (as new). I used it a few times, it is a monster and requires all your concentration. The power is huge, is takes a lot for the LED's to change from green to yellow, let alone red. The output of the motor is about 2200 Watts (almost 3 real HP), but the drive friction eats up 300 to 500 Watts. When the blade should stall due to unexpected forces in the cut wood and you don't shut down instantly, the drive cone lets loose such local energy on the ring flange, that a blue spotweld-like stain burns its way all through to the other ring side. It reminds a bit of friction-welding. This is the most awesome handheld circular saw i know. Holz Her stopped making them long before Reich's hand held machine division itself was purchased by Festo, because these machines were just too expensive to make and too finnicky to operate. I wonder: was there ever anything bigger than this in Aus or NZ?

Greetings,

Gerhard
Amsterdam, Netherlands

Gerhard, I've been working on a series of old University accommodation blocks, gutting and restoring/renovating them to modern standards of fire protection, electrical safety and living standards.

Some of this work has involved removing structural masonry walls and adding steel beam reinforcing for the additional loads of upper masonry levels. This has necessitated piercing the large reinforced suspended concrete slab flooring. To this end the demolition experts have needed to use diamond cutting apparatus to penetrate through about 250mm of solid concrete steel reinforced floor. They have been using...... a purpose built ring-saw! This machine, made by Husqvarna /Partner utilises a 2 cycle power unit from their range of chainsaws and concrete cutters. Quite large, extremely powerful and very very loud. In fact, the noise and fumes are so bad in the confined and enclosed spaces that we've had to evacuate the floors in which they were being used.

Talking to the fellows using the tool, which was hired specifically for the task, the ring is about 14" diameter, with an effective depth of cut of about 10". The saws, apart from the obvious differences of using gasoline rather than electric power, are otherwise superficially similar in their disc drive and control mechanisms. There's also hydraulic versions available too, which would have been more appropriate to our particular workplace, given that other tradespeople were trying to work in the same space also.

The other major difference of course is that the sawteeth were replaced by diamond sections brazed to the outer rim. These appear somewhat wider in section to those on other concrete saws I've seen, as was the disc or ring, perhaps due to the relative instabilities inherent in the ring saw's drive. I was told that the ring, while robust and long lasting, was nevertheless subject to damage by rough handling. The replacement cost for a ring, which was apparently not easily user replaceable, was in the order of about AU$1000!

So it appears that Reich's original design is alive and well, and used by yet another manufacturer in another guise. I'm left gobsmacked by the ingenuity of the original designers of this ringsaw technology.

Hi Ratbag,

there are a lot of ring saws in use in the industris around marble and other decorative stone. Over the years, manufactuers managed to get the rings larger in diameter and the difference between outer and inner diameter smaller. These thin rings are even used to saw in curved lines, which would not be possible with "full disc" circular saws. Husqvarna is indeed a big name in portable ring saws, with the hydraulic K3600 being the most prominent. It features water cooling and all the holes and nozzles emitting water jets and spray, are clearly visible. These machines can even be used under water und when used in open air for demolition or sawing windows in stone walls, the cooling water is also used to trap stone dust, helping to make the air around the workoplace a bit cleaner.

And John from Berlin! I totally failed to notice your post, my sincere apologies for that! In the mean time the RKS 160 you mean (earlier type name 278) has been added to my collection. It features a 2000 Watts motor of Holz Her's own design ,that was also used on their regular circular saws in that era. The motor has a spur type gearbox (like that of a circular saw), the output arbour of which drives the conical friction drive wheel. There are some pics of this saw below.

greetings all!

gerhard