The HTC 800 Classic is a powerful, robust machine that is very easy to operate. The Classic model is fitted with the extremely reliable neb hub system, which reduces the need of service and maintenance. Other features include:
- 15 HP motor fitted with three grinding discs
- Machine size handles large grinding areas, delivering high performance while being easy to handle
- Grinding pressure is controlled using movable weights
- Economical in design and use
Watch this video for a comprehensive, hands-on introduction to the HTC 800 Classic Grinder. Surface Prep’s own Dan Knuth demonstrates how it operates, important information about the grinder and how to troubleshoot common problems with the grinder. Below is a written overview.
Planetary, Counter-Rotating Grinding Feature
The 800 Classic uses a planetary component where two different grinding motions work simultaneously. It is a counter-rotating grinder. The entire unit itself is turning counter-clockwise while each of the three satellite tooling heads turn clockwise.
Rigid & Flex Plates
Two types of plates can be mounted to the grinder.
- Rigid Plate – an all-metal plate, there is no flex to it at all. Metal bond tooling, PCD tooling, any aggressive type of tooling that’s going to grind or cut should be mounted to a rigid plate.
- Flex Plate – this plate has a little give to it, which is going to protect against any type of foul scratching. Resin-bond tooling and transitional-type tools used in honing stages of a project should be mounted to a ridged plate.
Mounting Diamond Tools on the Rigid & Flex Metal Plates
The 800 Classic uses HTC’s instant diamond tool change system called EZchange™, an ultra-fast system for changing diamond tooling. You will notice that there are six beveled shoes located around both the rigid plate and the flex plate. The back of each diamond tool is also beveled. There’s only one way each tool can be attached to the plate. Simply slide the slot of the tool over the wing of the shoe, lining up the bevels, until it will go no further. Then with a hammer or rubber mallet, gently tap the diamond in to secure it.
Changing Tooling Plates
Once all the diamonds are loaded, mount the plate onto the grinder. Simply line up the plate notches with the grinder notches and drop each of the three plates into place.
There are two ways to secure the plate to the grinder safely. 1) turn the middle key on the grinder completely, which will prevent that plates from sliding off. 2) Put screws in each of the six screw holes on the plate. The centrifugal force of the grinder will hold the diamonds in place, so there’s no concern with the tools flying off.
Shrouds: Floating Plastic & Flexible Rubber
The 800 Classic has two types of shrouds, depending on the age of the grinder. The newer models will have a floating shroud, which will automatically adjust itself to the floor and the height of the diamond tooling. It’s a much better design when it comes to controlling the diamond dust and automatic adjustment to the contour of the floor.
The other type of shroud for older models is the Velcro® shroud, which is attached to the grinder using a Velcro strip.
A couple of things you want to be sure of – since the heights of the diamonds change and the contour of the floor may change, make sure to check frequently that the shroud is sitting at the proper height. The shroud should be resting on the ground when you attach it to the grinder. If it’s too high, no vacuum seal will be created and the dust won’t be contained efficiently. If it is too low, the shroud can fold underneath the grinder and get chewed apart by the diamond tooling.
Changing the Weight of the Grinder
Three separate weights are added to the 800 Classic, which influences the downward pressure on the diamonds. Each weight is about 38 pounds and two of the weights can be removed to adjust the downward pressure. Each weight has two tabs in the back, two on each side and one in the front. When removing a weight, pull it away from the grinder motor for ease of removal.
Wet Grinding Water Container
A wet grind uses water in order to grind and polish, keep the diamonds cool and cut more efficiently. The water tank is located on the front of the 800 Classic in front of the electrical boxes, and has a hole at the top to fill the tank. A water line runs down, out of the bottom of the tank, carrying the water to the front of the grinder, where it is emptied out and used with the diamond tooling to make the cuts.
Powering the Grinder
The 800 Classic comes with a 50-foot cord that plugs in to the side of the electrical box. There’s only one way to plug it in. You’ll notice a notch on the plug that corresponds to a notch on the receptacle on the electrical box. Those notches line up, the cord slides into place completely, and the cord cover fits into a tab located on the electrical box. The grinder is plugged in properly when the three indicator lights at the top of the receptacle light up.
Accessing the Electrical Box and Computer
The electrical box is located in the back of the grinder. To open it, use the included key or a flathead screw driver to turn the locks on the top and bottom of the door panel. Inside are guts of the grinder – the inverter or computer. For any reason the grinder shuts off, a fault code will appear on the computer readout screen that corresponds to information located on the inside door panel or in owner’s manual. You can also contact Runyon Surface Prep and talk to one of our repair technicians or research online. Other information is included on the inside of the door panel as well, such as the unit’s serial number, electrical requirements, etc.
Grinder Control Panel
On the control box is at the top of the grinder and contains six buttons:
- Emergency Stop (red) – cuts all power to the unit when activated. To restore power, depress and turn the emergency stop button until it pops up, and off.
- Duty light (green) – next to the emergency stop button. Electricity is powering the grinder when lit.
- Reset – clear any computer error codes by pressing this button.
- Potentiameter – next to the reset button. Controls the speed of planetary rotation.
- Forward-Neutral-Reverse – bottom left side of the control panel. Controls direction of planetary rotation. Please note: Correct rotation direction is important when using directional tooling such as PCD diamonds.
- On-Off – after disengaging an emergency stop, turn the grinder back on here; the duty light should illuminate green, which indicates power has been restored and the grinder is ready to begin working.