I have made a bunch of these for spacing both the prop and front bulkhead by drawing the spacer in autocad. I print the spacer drawing out with drill hash marks for the center hole and prop bolts. Cut it out and use spray adhesive to glue it to the metal. I cut the rough shape on a bandsaw leaving a little margin for error. I then us a table sander to sand it to the outside diameter on the paper. I center punch the bolt holes and drill the to size starting with a 1/16" for accuracy.
The center hole is a bit more challenging. If the spacer thickness is under .040, I drill it out big enough to get a nibbler in there and nibble around the id of the center hole and file to shape. You need to be accurate, but its ok to have it .020" big. With thicker material, I drill holes around the id of the center hole, knock out the middle and file to shape. Jeff On 2/22/07, Mark Langford <[email protected]> wrote: > But the easy and simple way to do it right is to cut out a 5" or 6" > diameter spacer out of aluminum (whatever diameter the prop hub is), using > the crush plate as a jig to drill the center hole and the six bolt holes. > You can cut this out on a bandsaw if you are careful, but the center hole > will problably require a lathe or a mill. If you do machine it, you might > as well cut the outside diameter the same way and then match drill the six > holes on a drill press. I wouldn't be surprised if Steve Bennett at sold > something like this. See http://www.greatplainsas.com/scphub.html for > something he calls a prop "face plate", and although it appears to be steel, > it would certainly be easy and cheap, at 8 bucks! He might also sell one > made out of aluminum. If not, it sounds like a manufacturing opportunity to > me. Ken Brock probably used to sell these, but I believe the company met > it's demise shortly after he did. > > I just checked your website at http://home.hiwaay.net/~langford/wcrawford/ > and that is a gorgeous airplane! And since you are using a Continental, you > need an SAE-1 crushplate. Aircraft Spruce sells these, but they are also > steel. You just need to find an aluminum SAE-1 crush plate, and use it for > a spacer... > > Mark Langford, Huntsville, Alabama > see KR2S project N56ML at http://home.hiwaay.net/~langford
