With the new high speed spindle on its way I need to make a mount for it. On the Fadal mill the part of its spindle housing that protrudes below the head has a cylindrical part that is 5 inches diameter by 2.5 inches long. I want to make a clamp that will fit this. The clamp will have another hole bored for the new high speed spindle (HSS). The centerlines of these holes are 6.25 apart. This allows the HSS to be clamped near its nose and for the side of the HSS to clear the head of the mill. The holes to be bored in the clamp are 5.0" and 3.0" diameter and there will be 2.25 inches of material between the holes. The outside dimensions of the clamp will be 2 inches larger than the bore holes, which means there will be 1 inch thick material surrounding the holes. I will mill the outside of the clamp so that there will be two flat surfaces that will be tangent to the rounded ends of the clamp so that the clamp will be sorta teardrop shaped. The mount will be 2.5 inches thick. I plan to use two 3/8 cap screws for clamping each spindle. The mount will be split in two places for clamping. These splits will be parallel with the long axis of the mount. I have though of other ways to split the mount but don't know if they are any better. The mount could be split between the holes and then only two screws would be needed for clamping as the screws would draw both holes tighter at the same time. I could also put the splits at right angles to the long axis of the clamp. This would leave more meat for threads but would also make the tightening screws for the big hole hard to get at because they would face toward the back of the mill. I would like to use Dura-Bar as the material but don't know yet where to get a piece that's 7 by 12.25 x 2.5 thick. I could use
6061 but I don't know if it would tend to ring and cause unwanted vibrations, which would lead to poor finishes and broken tools. Suggestions are welcome. Thanks, Eric- posted
7 years ago