Challenging Job On A 109

ericc

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Finishing a faceplate on a craftsman 109 lathe was a challenging job. This required trimming the outer rim of a 4 1/4" round. Even with the compound and cross slide all the way out (handles foul) it is hard to reach the rim with a tool. The rim was ragged and it was an interrupted cut. Furthermore, the edge was torch cut. No matter what expert machinists say about it being impossible to add carbon to a torch cut, it really was hard. The first few thou threw sparks with HSS. I had to hold the compound down since the cross slide was only partially engaged. Anyway, it barely worked. This is really a 3" lathe, especially for steel.
 
Hi Charles. I did use an angle grinder to remove most of the nasty ridges from the torch cut but there was a little left. My comment was partially a remark on a post on another site about myths of machining. But it is not a myth. Torch cuts can have hard spots. So can welds, especially forge welds. Anyway, that little lathe was working hard!
 
On a 3996, the way to work up near 12" OD is to turn the compound around so that it points at the operator instead of away. And mount a backwards boring bar as short as possible. That keeps the cross slide fully engaged.
 
Hi Ericc,
It isn't so much the flame cut that makes it hard it depends on what is in the steel to start with and if they quenched it or let it cool down slowly. I used to use the same trick to grind off the skin before cutting but you have already figured that out. The blokes I used to work with said that plate steel was made from used ball bearings and old car bodies so it was always a bit of a mixed bag.

The Swing of a lathe refers to the maximum diameter that can spin around and clear the bed. My Atlas is a 10" and it is no coincidence that the center height is exactly 5". So actually turning 10" outside diameter would be virtually impossible. However I could probably mount a 10" job and work on diameters closer to the center.

I have been thinking about making a face plate for my lathe. I'll start with a 6" piece that I have lying around and call it a drive plate. I don't know if I'll be ambitious enough to try and make a 10". (although I'd like one)
Yours looks good in the pic
David.
 
Plus that little lathe needs a mirror image pulley set to run back gear properly. I had a dream of making them then got sidetracked. But I have 4" aluminum already cut if you need a piece to make a pulley....Bob imum
 
I just spotted what is described as being an original face plate for a 10-12" Atlas lathe on ebay.
The OD is 8 1/2 inches. Hmmm I wonder if I should buy it :)
 
Depends on the price. Folks told me I was crazy to make my own if you can buy one on Ebay for $25. But that is for the 1/2-20 spindle thread. Mine has the (rarer) 1/2-24 thread.
 
On a 3996, the way to work up near 12" OD is to turn the compound around so that it points at the operator instead of away. And mount a backwards boring bar as short as possible. That keeps the cross slide fully engaged.

That's a great idea. I think it would work. As for the boring bar, that would hold a conventionally ground lathe tool so one could kind of get around the side of the piece that is being turned?
 
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