While I am waiting on some metal for the fingers on my bending brake, I thought I would get back to this project.
I spent a lot of time deciding what I wanted in this grinder and while the table provides the X and Y movement, it would be so easy to make a tilting head similar to the Cutter master machine and be able to grind end mills and drills, BUT, I wanted more capabilities without getting complicated. I love the Bonelle grinder I made but it is too complex and time consuming to set up every time you want to do something. I want it to be easier and simple. So......... I studied several brands and looked at the features and came up with a design that will fit all my parameters. I also want this machine to be very heavy and stable. I think I have it now. this machine will take two men to pick up and move. It will be heavy
, which translates to sturdy. It will not be a whole lot bigger than the Bonelle, but will be higher and deeper. I spent a lot of hours designing the grinding head and column. I have it detailed enough to start construction.
This is the drawings for the grinding head. it is made from a 4" X 4" X 4 1/2" block of 6061 aluminum. I am using this because I happen to have it. Cast iron would be better, but......
The column will be 2" diameter cold roll bar. Again because I have it. I was thinking bigger but that would increase the head size also , so a compromise. There will be double split cotters to lock the swivel head in position. The motor will mount directly on the grinding head and the wheel will mount directly on the motor shaft. ( Now before a bunch of you flood me with the thought about vibration in the cutter wheel mounting it directly on the motor, I have researched this and even tested the idea. As long as you have good quality ball bearings in the motor, it is not a problem and the 60 cycle frequency has no effect that can be detected). The motor will swivel 360 degrees as will the column also, making any angular position possible with just two settings. The column and swivel head will be marked in 1 degree increments but with the spacing on the marks you should be able to set a 1/4 degree with great accuracy. The column will rise and lower just like I did it on the Bonelle. There will be a precision acme screw, 1/2"-10, giving .100" travel per turn and I have an anti back lash nut for the screw, eliminating any back lash in the assembly.
The degree markings for the motor swivel and the column swivel will be engraved on a 4" diameter wheel. this should make the one degree marks approximately .127" apart. That is why it will be easily set accurately.
There are three bolt clamps in the rear of the head to secure the head to the column. The top and bottom bolts will be lock bolts ( have a nylon insert in the threads to hold their setting). These will be set to put a light drag on the head sliding on the column. the center bolt will have a 1/4 turn locking handle to secure the grinding head at any setting vertically.
I put the aluminum block in my 4 jaw chuck to face the front. this will be the reference surface everything is measured from. All the machining for this view on the print will be completed before it is taken out of the chuck.
The face is flat and smooth. Ready for finish machining. I will get more done this week end.