Single Point Metric Threading On The 618

[heiko910]

Heiko,

The Metric trans-positioning gear pair that Atlas used in their tables are 52 and 44. Which happen to be included in the standard set of change gears that shipped with all of the Atlas and Atlas-Craftsman 6" lathes. So I wouldn't buy the 47/37 pair because (a) you should already have the 52/44 pair and (b) the 47/37 pair wouldn't match the Atlas metric threading tables.

The one extra original that I have of the 1954 Atlas MOLO cost me $54.50 plus postage. As I've written elsewhere, the average price of MOLO's on eBay is about $35.00. I wouldn't have paid that much for one except that at the time it was one of the few that I hadn't yet acquired. I was in a little bit of a rush to complete the MOLO history that I was writing and that issue was one of the few that I still didn't have. If you want it, fine. Send me a PM with your name and address. If you don't want it, no response is necessary.

Alternatively, you can set up a search on eBay as I did, although you can expect a lot of false hits as eBay is more interested in selling stuff than they are in someone finding what they were really looking for. But it may take you quite a while to find what you are looking for as most eBay sellers are clueless as to what keywords to use. About the only thing that most of them will do is to include a photo of the Copyright Page and the front cover. Beginning in 1954, Atlas began including the print history between 1937 and the year that the particular copy was printed. So you would be looking for 1954, 1955 or 1957. And it really doesn't matter whether the front cover is a gray Atlas one or a black Craftsman one as in any year from 1954 on, the only difference between the two versions were the covers. FYI, between about 1939 and 1953, all covers were black Atlas ones. And probably only one year did a few of the ones printed cover the 618. In 10 years of looking, only twice have I found one Copyright 1937 that covered the 618. I don't know whether or not they ever printed one that covered the 101.07301, although I am still looking.

Hi there,
I got a PDF of the molo that covers metric for the 6 inch lathe but a couple of standard metric thread pitches are only doable with gears at the D position. The Chang gear bracket in my lathe doesn't have the D position. In the manual it states that an extension bracket is available from the factory. I wonder if I can still find one today (40 years later) and what that would look like.
See the picture, in the text above the chart it talk about the D position.
The other picture shows what my gear change bracket looks like. No D position.
Thanks for your advice,
Heiko

 

[heiko910]

One of my projects will require me to cut a 1.80 mm thread. That is a real odd ball thread. I was getting nowhere in trying to figure out what gears I needed to cut that thread until I converted it to threads per inch. To convert to TPI first divide the metric pitch by 25.4 to convert it to inches and then divide 1 by the number you just calculated to get imperial TPI. In my case 1.8/25.4=.0708661. Then 1/.0708661=14.1111. I looked in the manual for the QCGB on my lathe and found a gear combination that would cut 14.1136 tpi. That is only off by .0002% which is close enough for a short thread.

That is a good piece of information. Thank you.

 

[wa5cab]

I tried to call Clausing to see whether or not they knew the part number of the add-on to the 6" change gear bracket but couldn't get past their computer. I'll try again later.

 

[heiko910]

I tried to call Clausing to see whether or not they knew the part number of the add-on to the 6" change gear bracket but couldn't get past their computer. I'll try again later.

That is very nice of you. Looking forward to your findings. I wonder if I could get a bracket of a 10" lathe to work on my 6inch lathe.
Thanks, Heiko

 

[wa5cab]

I suspect that the 10" bracket would be too large, both in the space that it would take up and in the hole at the right that is concentric with the lead screw. The latter problem could probably be fixed with a reducing bushing approach but the slots being too long would require something like cutting off the left end concentric with the lead screw and then brazing on something like a radious'd piece cut from plate to close up the slots. And then machine the back side a little bit to bring that surface back flat. Maybe someone with both a 6" and a 10" will look into that.

Yesterday, I finally managed to get through to Ron McNett at Clausing. He wasn't really familiar with the add-on for slot D but promised to look for the drawing. So it is now wait-and-see time.

 

[heiko910]

That is so cool.
I hope they can find the drawing of this extension bracket. I bet it was not a very common accessory.
, Heiko

 

[wa5cab]

Ron found and sent me the drawing and the one page owner's manual/parts list for what was apparently the kit that included the bracket and the nuts, bolts, washers and parts necessary to install it.

Although it doesn't explicitly say so, the material for the bracket is given on the drawing as cast iron. So I would assume that there was a casting involved. However, I see no reason why 1018/A36 flat bar wouldn't be satisfactory. There would just be more material to remove.

There is one thing about the drawing that I do not understand. As it is unlikely that anyone still at Clausing has ever seen one of the brackets, asking anyone there is unlikely to explain it. So someone will just have to make one to find out. Making it is pretty much straight mill work and hole drilling except that it will require a rotary table.

When I get the two sheets added to Downloads, I will let you know.

 

[heiko910]

Ron found and sent me the drawing and the one page owner's manual/parts list for what was apparently the kit that included the bracket and the nuts, bolts, washers and parts necessary to install it.

Although it doesn't explicitly say so, the material for the bracket is given on the drawing as cast iron. So I would assume that there was a casting involved. However, I see no reason why 1018/A36 flat bar wouldn't be satisfactory. There would just be more material to remove.

There is one thing about the drawing that I do not understand. As it is unlikely that anyone still at Clausing has ever seen one of the brackets, asking anyone there is unlikely to explain it. So someone will just have to make one to find out. Making it is pretty much straight mill work and hole drilling except that it will require a rotary table.

When I get the two sheets added to Downloads, I will let you know.

That is great news. I would definitely be willing to give it a try.

 

[wa5cab]

OK. I'll get them added to Downloads in the next few days. Right now I am 'way behind on my general emails.

 

[heiko910]

Ron found and sent me the drawing and the one page owner's manual/parts list for what was apparently the kit that included the bracket and the nuts, bolts, washers and parts necessary to install it.

Although it doesn't explicitly say so, the material for the bracket is given on the drawing as cast iron. So I would assume that there was a casting involved. However, I see no reason why 1018/A36 flat bar wouldn't be satisfactory. There would just be more material to remove.

There is one thing about the drawing that I do not understand. As it is unlikely that anyone still at Clausing has ever seen one of the brackets, asking anyone there is unlikely to explain it. So someone will just have to make one to find out. Making it is pretty much straight mill work and hole drilling except that it will require a rotary table.

When I get the two sheets added to Downloads, I will let you know.

Any news about the downloads?
Thanks, Heiko