Making a new mill over arm, accurately measuring long distances?

p.s. as a new post since I can't edit the previous, I could probably come up with an internal micrometer, or a height gauge and surface plate, depending on exactly where you need to take measurements.

Bill

Except for that lip to the left there isn't really any point thats thicker than the over arm so can't bore it out. You can kind of see the bronze lump welded the the original cast part. The 15.85mm bore only goes 16mm in which isn't in my mind the optimum bearing size for the forces involved.

Mark, how long has your ball bearing been working? My only concern is having the bearing being pressed on and off hte arbour a lot and something wearing away. Not sure what sort of tolerance would give the least interference while still engaging the bearing. I am pretty terrible historically speaking at making bearings fit properly.

I can't remember where but I saw a guide on the internet ages ago on making cotter pins while restoring a capstan. If anyone knows he one I am talking about it would be handy to have a link for reference and also posterity. Can't say I currently have the GHT book but I have a vague idea how to make them.

Also thanks for the offer of the somewhat closer calipers :v Been a long long time since I used manual ones. I think they are surplus to requirements now however. Times are a fair bit hectic at the moment, might see you some day though.

edit: caught out by the secret second page, double thanks for those offers. Though not necessary for the current job its good to know someone generous is close by. 

Edited By Rainbows on 07/09/2017 00:36:30

Here is how you can bore it in place. Clamp the arbor support to the overarm. Leave the overarm clamps loose enough that the overarm can slide. Grab the lower end of the arbor support in the milling vise. Use your Y axis feedscrew to feed the arbor support onto the boring tool.