Challenging Job On A 109

[ericc]

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.

 

[ericc]

Picture

 

[Charles Spencer]

I'd have ground off the edge until the torch cut was no longer visible and it was roughly round.

 

[ericc]

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!

 

[wa5cab]

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.

 

[pollardd]

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.

 

[aametalmaster]

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

 

[pollardd]

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

 

[ericc]

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.

 

[ericc]

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?