Reconditioning a Relmac lathe

[BillTodd]

interesting but don't see how to get it parallel to ways... these boring machine assume a cylinder block or similar to sit on that is a known perpendicular to the hole to be bored.

You just need to create a known perpendicular with a couple of right-angle plates, referencing the face and edges of the lathe bed - The boring bar has a built-in three point reference to centre itself in the bore.

My current plan is to make a saddle out of 1/2" ground plate, approx 8" long which will be bolted to the apron in place of the real saddle and will carrry two braced uprights with oilite bearings

Ok Sound's like a plan, but seems like a lot of effort - you are, after all, making a complete new spindle boring tool. If you have any kind of removable lathe spindle head (e.g. Southbend type) that could carry a long boring bar, it could save you a lot of work.

Are you going to use the existing lathe to line bore the two new bearing holes in the saddle part? (see attached example) (this would ensure the height and alignment of the boring spindle is correct for the lathe).

Just a thought; What about a couple of self-centring bearing blocks and a length of shaft - i.e. cross drill the shaft at one end to hold a cutting tool. Mount the shaft and bearing between centres while you tighten the bearing blocks to ensure everything is in-line.


BTW How big are these Relmacs?

The pictures show the set-up I used to line bore the bearings for a motorcycle headstock.

The 1" steel bar is held in a collet at one end and a revolving centre at the other. It is cross drilled to hold a cutting tool (broken 6mm carbide end mill).

The second picture shows the use of a DTI to set the cut depth.

You could probably use a similar set-up to bore the bearing holes for you spindle boring tool - that way the new holes would be perfectly aligned with the old spindle.