Elevating boring table for lathe cross slide.

Agree with Michael that screen shots from his link would be good enough to work from.

There may well be stability issues due to overhang with a larger version sized for the 12" swing Atlas that Dennis has.

I'm tempted to use it as a starting point for one to fit my Pratt & Whitney Model B which is even bigger. if the customer job I'd need it for materialises I shall turn the design through 90° so the adjuster is at the front or back and arrange shim carrier supports onto the saddle wings. Rather than relying on the elevating screw and column for stability under load I shall drive it down onto shim-stacks to set the height and bolt it in place. The screw merely being a convenient way to lift the table for adjustments.

I shall be dealing with a 5 inch or so diameter hole with appropriately sized tooling so it's has to be stable. Hopefully the customer will be scared off by the quote but if he insists I want some nice tooling out of the deal as well as useful amounts of cash.

Clive

Yes it looks a bit unstable cantilevered out from the round column like that, rather like the table on a drill press. But some jacking screws at each corner could soon sort that.

Not sure if this is useful to you (unless you know someone with a horizontal mill at your local ME society) but you can bore between centres on a Horizontal without too much effort.

Obviously you can use a boring head too but that might not have the reach required. I have a photo of this operation somewhere but can't put my hands on it at the moment. Needs a special 'centre' (or holder) made for the other end of the overarm and careful setting up. Not a proper Horizontal borer of course but usable for really large/awkward parts.

Regards,

IanT

Picking up on Hoppers comment about screw jacks and running with it I wonder if having the boring table simply jacked up and down guided by stout columns attached to a fixed under plate might be a better way.

The 6" Atlas Craftsman Dennis uses has much more room above the cross slide than the usual run of Model Engineer home workshop lathes we are used to. Look at the lower pictures here to see :- **LINK**

http://www.lathes.co.uk/atlas/page4.html

It would seem feasible to attach a stout square or rectangular plate to the cross-slide with a cylindrical column at each corner with the boring table proper running up and down it. I guess something in the 1" to 1 1/2" diameter range would work for the columns. Maximum stability would need some sort of locking arrangement to securely lock the table to the columns after setting. Something a simple as a slot and pinch bolt in the side of a guide hole should do.

Simplest way to lift things would be a fine thread bolt close to each column. Turns counting would get you close to even adjustment. Add a hole for a depth micrometer, vernier or digital gauge to measure things would let you set each corner just so. It would seem best to have some way of locking the table down onto the jack before clamping up the pinch bots or whatever. Probably such provision is essential if downwards adjustment is to be reliable.

Plenty of ways to refine the idea or modify to suit components on hand and/or economical to purchase. Putting a fine thread on the guide columns with suitably calibrated lift nuts for direct setting sounds attractive. However such will be hard to engineer if absolutely positive setting is needed and clamping the boring table to the column after setting for maximum stability difficult.

In my working days I built a large system of this ilk using the Thor Labs 2" column / rod system and aluminium breadboards with simple screwed rods for jacks. The carriers riding on the column acted as guide bushes and, being something over 3" long, made the whole thing incredibly stable.

Clive

Edited By Clive Foster on 08/12/2022 13:52:08

Clive

Your description made me think of the elevating tables on woodworking planer/thicknessers. Mine has a single central column directly under the cutter block, an approach taken by a number of machines including, I think, the Stepperhead by Alan Jackson. Obviously, this is unlikely to work as a retrofit to a conventional lathe.