Mill or lathe?



You appear to be inexperienced in machining and using a drill press to carry out milling operations is a disaster waiting to happen, even for "experienced machinists".

A post-type vertical milling machine is an inexpensive way to start milling operations.

A rotary table allows the work mounted to it to be rotated past a cutter, or used for positioning such as drilling holes on a bolt circle.

The rotary table is usually worm gear driven at crank-to-table ratios varying from 40:1 to 90:1, with 60:1 and 72:1 other common ratios.

By fixing the work piece to the rotary table top you can machine the outside and inside diameters of thin disks in one set-up provided that the remaining ring is fastened to the rotary table top. Here cleverness in workholding pays off in spades and $$$$$! One way is to use finger clamps and transfer these from the inside of the ring to the outside after milling the outside diameter.

Because of the worm gear reduction it can get tedious turning the crank (hand wheel) to rotate the work past the milling cutter hence the advice to add motor drive to it. A variable speed electric hand drill would suffice if you don't mind the noise. Again inventiveness is the key to a low-cost solution here.

With clever fixturing you can finish the entire ring with one set-up on the mill! For example you could bolt a piece of MDF onto the rotary table and glue the work piece to this for the polishing operation. If you glue the work piece from the start then for the milling operations finger clamps or wood screws would still be required for additional strength to resist milling forces.



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Will this not make shilling (is that a verb?) impossible? If you win as a shill the only way to hide the actual non-payment from EBay will be claiming cash for a direct pickup. OTOH, why not?

The most recent changes really do not make it worth while for small sellers to use EBay:

1) Compulsory PayPal, insertion and final value fees will make the EBay take on your sale 30-40% on low value items. 2) Shipping cost upper limits mean that EBay will get more money in final value fees. BTW I eventually found the actual figures which are well hidden on EBay web site. I used to sell books from Canada and this is now dead. The maximum shipping on books is $4 which is about half of the cheapest postage let alone packing etc. Including the postage in the price of the item for the low-end collectible books is just not an option. 3) The whole fee structure seems now heavily skewed to fixed price-high ticket items.

I know there has been a lot of similar comments here about EBay but things are getting worse by the day.

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Michael Koblic

"Ronald Thompson"

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Michael Koblic

I am gathering courage to cut a piece of 0.7 mm brass in a circular shape to fit one of the 114 mm dials. I have pretty much decided to sandwich it between two pieces of wood and use a spiral cutter in my plunge router. I have a pretty good jig for small circles from Lee Valley which should be just the thing for this. I expect to get a better result than trying to cut it with snips.

I have not even got to the stage of thinking about engraving. Actually, not strictly true: I tried manual engraving and sucked at it. Most of my faces are etched.

I was thinking along the pottery wheel lines...I am trying to visualize the sawmill...

The more I read this thread and the more I think about it the more I wonder if I am neglecting wood as a material to make some of these helpful things. ABout a month ago I read through a book on old technologies - the one thing that got my attention was making wooden bearings.

For the steel I found that magents are far the best *provided one is careful about heat*. I have killed a few by prolonged grinding of a small part held by four magnets which were attached to a wooden base. It is less of an issue with the bigger parts (and now with added awareness and caution). I re-made the jig for the small parts so it is all metal and conducts the heat away better.

I found that glue is great at rest, but the heat of grinding releases the glue and things start to move a bit, if not fly. I would have thought that for a rotating table at any speed for sending purposes symmetry will be an issue.

I made something similar with epoxy. It worked up to a point...

Indeed. That is pretty much what I do now if the surface is flat, without any lips etc. Sand paper in an angle grinder (120 and 220 grit), follow with palm sander down to 400 grit. It does not have to be flat completely, just

*look* flat. Well, not strictly true either. It is nice to be flat as the transfer of the comnputer design by the press-and-peel heat method works better if the surface is flat. But that is a whole different issue...

SOunds like something I should look at. The House of Tools sella "drill press lathe attachment" for $29.95. I have not seen it...

I think I undeerstood most of it. Anyway, I saved your post for further reference. So thanks again.

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Michael Koblic

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