Peter,
I'm a bit uncomfortable posting a plug for my shop however I'll gladly share some of my thoughts and goals when the KMG1 was designed.
1st: I have nothing but great things to say about the other machines mentioned. They all served as a benchmark for my work and I find it exciting to actually be compared with them.
I've studied all of the other machines making notes of the strengths and weaknesses of each and I've carefully listened to many makers who kindly offered their thoughts and advice. I thank them all!
In my opinion, the most impressive grinder is the Hardcore. I saw one, brand new, and fresh out of the shipping box. It presents itself as a truly remarkable piece of machinery. The fit and finish is superb and the design and form is breath taking. You would hate to scratch it!
In the beginning, I had to decide on the basic architecture of the machine. Either a front driven contact wheel (HardCore, BurrKing), or a rear driver with a coasting contact wheel (Wilton, Baders).
I opted for the rear driven chassis focused around a common tooling arm because I felt that it offered more flexibility and convienence.
A problem that I saw with the Wilton was that it doesn't have the wide range of adjustment that the Baders have so that you can run big 14" wheels down to say a 3" wheel and take up the belt slack by simply sliding the arm in or out. Heck, if it is easy to slide the tooling arm in and out, then it would be very convienent to have multiple tooling arms with different attachments for very quick change overs. I couldn't think of a practical way to do this with the front driven wheel design.
The next decisions focused on structures and materials. Since the grinder is not intended to fly or to float I didn't worry about weight. A KMG1 with an 8" C-wheel weighs about 125lbs w/o a motor. After reviewing the structure of the Baders, and the Wilton grinders, I wanted to optimize the chassis stiffness. Rather than using a common vertical plate, I designed the KMG1 chassis as a rigid tooling bar reciever mounted on risers from a wide base plate. The main risers are mounted laterally (sideways from left to right) for side to side stiffness, and they are tied into the rear bearing plates which offer front to rear stiffness. The material is standard 1018 CRS. The tooling bar size was increased over the Bader bars to 1.5" sq. This was to add more mass and stiffness for vibration damping and smooth operation. From front to back , side to side, and up and down, I think the KMG1 is more rigid than the others.
The end of the tooling bar has a series of vertical and horizontal threaded holes. These holes are intended to be used for any number of attachments. Basically I knew that I couldn't think of every attachment concept up front so I made the tooling arm with options to grow into. Hence the birth of the "Big Wheel" set-up with the external pillow block bearings, or a small wheel attachment that can accept the hardcore wheels, or a belt driven disk attachment,...or how about a belt driven buffer attachment, ..or how about a variety of grinding jigs and fixtures. Since I didn't know what ideas might pop up in the future, I knew I had to make the tooling arm flexible in its function and robust in design.
The KMG1 is hand built in my shop here in Ohio. I do all of the work myself on conventional machine tools that typically wear the name of the city they are/were from (ie Bridgeport, South Bend, Cleveland,Kalamazoo..etc.) CRC supplies the contact wheel tires. The 8" and 10" wheels are the C-134 tires fitted onto my own hubs. They are a quick change type and are available in smooth or serrated. The smooth tires are .100" larger in diameter than the serrated tires. The idea is so you can use a serrated tire for speed with coarse belts, then switch to a smooth tire for finishing with fine belts. Coarse belts are thicker, for example an 80 grit may measure about .075" and a 220 grit may only be .025" thick. This difference of .050" thickness is .100" on the diameter of a contact wheel. By switching wheels from roughing to finishing with the respective belts, you can match the groove to the grit and theoretically reduce finishing work. I'm sure this idea may spur some debate, but my point is that there are options for the beginner to the seasoned pro. The 12" and 14" wheels are the C-200 series. The platen attachment is very straight forward except that the platen itself bolts on and can be easily replaced. It is simply a 1/4" x 2" steel plate. It is simple enough that you can make your own variety of sizes, shapes and materials. No glass here please!
The KMG1 grinders do not have a fancy finish or paint job. They arrive at your door in bare steel as processed. They are now shipped assembled and tested. I'm currently using FedEx's new ground service because they can carry packages up to 150lbs. The grinders are crated and boxed.
As far as motors: I leave this up to you and your resources. In the event that you have something laying around, there is no need to buy one. I recommend nothing smaller than 1 hp and wouldn't hesitate to use 3-5hp if the price was right. For variable speed, there is no reason why you cannot use a DC motor and controller, or an AC inverter and motor, or pulleys with a constant speed motor, or a line shaft from a water wheel, or if your are doing an outdoor demo...use a Briggs and Straton. Here in my shop for a demo, I have a 2hp VS dc motor and controller setup with a 3 groove step pulley combination. This way a potential customer can "turn the knob" for speed controll and try it, then leave the motor at a constant speed around 1725 rpm and flip the belts to see what the step pulley set up is like. My opinion for a KMG1 is that VS dc motors are a bit over rated but a neccesity on machines with integral motors. My thinking is that belt speed is belt speed...the only difference is how you get it. If I flip a v-belt out of one groove on a pulley and into another so that the grinder runs at say 500 ft/min then flip the belt into a different set of grooves to get 3000ft/min.....the outcome will be the same as if I "turned the knob". How many DC motors and controllers do we see on drill presses? The KMG1 grinders offer this flexibilty and potential cost savings because the motor in not integrated. By the way, I love to turn the knob rather than flip the belts.
Well, these are just some of my thoughts. I sincerely appreciate the opportunity to be included in an open discussion and comparison with the machines mentioned.
If you are ever in the central Ohio area, feel free to drop me line and stop by. As with all of my work and to all my customers, I've always extended the policy that if you are not pleased with the item that arrived at your door, I encourage you to send it back to me and accept my humble apology for wasting your time.....no one has ever returned anything .....yet....(knock knock)
My web site is terribly outdated and many of the photos are of the original prototype grinder. I've made several enhancements since the photos were taken and I can't seem to find the time to get the web site updated. If you don't see what you need to see, drop me a line and I'll email some photos.
Sincerely,
Rob
