Removing RCMK bearings

[Jim Allen]

One of my fellow boaters had a problem removing the bearings from RCMK machined bottom ends. Since there is a definite space between the the two bearings used on each side it is possible to make a tool to push either the inside bearing or the out side bearing out after heating the case. The photo shows the split tool which can be collapsed then expanded after placing it through the either bearing. A 6-32 set screw is used to keep the tool expanded once it is in place. The entire assembly with the tool is placed in the oven before pressing the bearing out.

Jim Allen

 

[AgafonovRoman]

Sweet Jim! What kind of material do you use for tool?

 

[Jim Allen]

Sweet Jim! What kind of material do you use for tool?

Any type cold rolled or tool steel will work. In the area that is going to flex, there is a .282" hole with an outside diameter of .406". This leaves .062" on each side to allow the piece to open & close.

JA

 

[Terry Keeley]

Cool! Looks a little like the old McCoy bearing pullers I have.

IIRC the McCoy tools used a 1/4-20 NPT thread to expand the mandrel, how does your's work?

 

[Jim Allen]

The 6-32, 1/4" long set screw, is removed to allow the mandrel to collapse. After the tool is inserted through the either bearing's inner race the mandrel is expanded by inserting the 6-32 set screw to it's full depth. The tool & the crankcase are both heated in the oven. Pushing, not pulling, allows the one bearing to be removed. The second bearing is removed by pushing also. I use my milling machine to do both operations to ensure squareness of the pushing operation. Bearing insertion is also done in the milling machine for the same reason.

The tool could be made of AISI O-1 tool steel, hardened & brought to a spring temper. This would make the use of the 6-32 unnecessary.

JA