Metric Threading on 12 x 36 w/QCGB

[roadie33]

Mike,

That looks like one of the copies off of eBay. Look on the back of the title page and you should see (assuming that they copied everything) a list of years beginning 1937. The last one is the year that the original to your copy was printed. So long as that is 1957 or later, it will have the correct table. For 1.5 mm you will need a 52T gear. The 40 and 48 (two actually) and the two keyed bushings necessary are already on the quadrant. Page 127 shows what should already be there. You remove the 40T and two 48T gears, move one of the 48T over to mesh with the Tumbler compound gear in the IN position, and install the 40T and then the 52T where the two 48T were. The 48T meshes with the 40T and the 52T meshes with the QCGB. For some metric threads you will need a third bolt, axle, keyed bushing, flat washer and nut. Plus various gears.

From 1957 on, the only difference between the Atlas and the Craftsman manual versions were the front covers. Because the only different between the lathes was the badge and nameplate.

Robert D.

They must not have copied that page because it does not list the date any where.

I can find the 52T gear but not the third bolt, axle, keyed bushing, flat washer and nut.
An ideas where to get them?
For a reasonable price too.
Also can you list any other gears I may need for doing Metric threading?
I would greatly appreciate it.

Thanks.

Mike

 

[wa5cab]

That figures. Reminds me of a surplus radio outlet that used to copy only the parts of the manuals that "they" thought were important. Look around page 123 for a page headed "Thread Cutting On The xxx Quick Change Lathe. Depending upon what year the original was, the Atlas and Craftsman quadrants may differ. But only in where the Adjustment Slot is. The metric chart should be on page 130 or 132. You can pick the gears that you need off of it.

As for finding the gears and the other parts, there are several sources. If you define "reasonable" as "cheap" instead of current market value, your only source will probably be here, the Yahoo Atlas_Craftsman Group, or on other machining sites that don't run you off if they learn that you own an Atlas. Otherwise, eBay for used, Clausing for new, and a few machine tool suppliers for either. For all but eBay, look up the part numbers and ask for them by number and name.

Robert D.

 

[benmychree]

After looking at the info and finding that I would need to purchase extra gears and other items. All of this to do Metric threads for a few projects is not cost effective for me. I compared what the extra's could cost and the cost of a good set of Metric Tap and Die. I believe that I will just purchase a set of the larger Metric Tap and Die and that way be able to do just about any size I should ever need.
I'll just stay with doing American threading on my American Lathe.

Thanks for all of the help.

The unfortunate thing with using taps and dies is that it is nearly impossible to have the resulting threads be perfectly axial with the part; they are likely to wobble to some extent. It is quite possible to do metric threads with nearly any American lathe if it has end train gears that are accessable (some are not). I contributed a table from American Machinist, with their permission to this site that lists all the change gears, and all the pitches that can be cut; I made all the necessary gears for two lathes in my shop, and it all has worked out fine. The gears called out in this forum will not create an accurate metric conversion, just a close approximation; to be correct, you need a 127 tooth gear with a 100 tooth gear keyed to it.

 

[VSAncona]

Conrad Hoffman has a really good article on metric threading here:

http://conradhoffman.com/metricthreading.htm

 

[roadie33]

Conrad Hoffman has a really good article on metric threading here:

http://conradhoffman.com/metricthreading.htm

Thanks.
That is a good article on metric threading.

 

[roadie33]

Just got a good deal on 15 New ER40 Collets for $85. )
1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4". 13/16", 7/8", 15/16", 1"

Now I'll have to get busy and finish up my ER40 Collet Chuck.
If it wasn't so hard to make the nut for them I would just use UNF threading instead of Metric.
Looks to be easier to buy the nut and thread the chuck to fit it. M50 x 1.5

 

[wa5cab]

benmychree,

To prevent the wobble, you can use a piloted tap wrench in either a drill press (for flat parts) or the tailstock (for round parts). For die nuts, you can buy several sizes of die holders that you can mount in the tailstock.

As far as accuracy of the metric pitch, I've seen somewhere a workup on that. According to it, the table figures are good to three places or better. So close enough for anything but a lead screw or similar application.

Robert D.

The unfortunate thing with using taps and dies is that it is nearly impossible to have the resulting threads be perfectly axial with the part; they are likely to wobble to some extent. It is quite possible to do metric threads with nearly any American lathe if it has end train gears that are accessable (some are not). I contributed a table from American Machinist, with their permission to this site that lists all the change gears, and all the pitches that can be cut; I made all the necessary gears for two lathes in my shop, and it all has worked out fine. The gears called out in this forum will not create an accurate metric conversion, just a close approximation; to be correct, you need a 127 tooth gear with a 100 tooth gear keyed to it.

 

[master53yoda]

Just got a good deal on 15 New ER40 Collets for $85. )
1/8", 3/16", 1/4", 5/16", 3/8", 7/16", 1/2", 9/16", 5/8", 11/16", 3/4". 13/16", 7/8", 15/16", 1"

Now I'll have to get busy and finish up my ER40 Collet Chuck.
If it wasn't so hard to make the nut for them I would just use UNF threading instead of Metric.
Looks to be easier to buy the nut and thread the chuck to fit it. M50 x 1.5

I bought 3 nuts on ebay for 19.00 that gives yoiu the ability to leave nuts on the most ocmmon sized collets that you use.

 

[roadie33]

Collets came in today. Ordered on Tuesday, arrived Friday. That was fast shipping.
They look good and each came in it's own plastic container with lid.
They even sent a catalog and it's got some pretty decent tooling in it.
http://www.dzsalesllc.com is the place I ordered from.

Also got a good buy $40 on some change gears on E bay, so now I can do Metric threading. :thumbsup2:


64A, 52A, 36A, 2 - 32A Gears

Should be good to go next week on getting the ER40 Collet Chuck done and see how the collets work out.

 

[roadie33]

Here is the finished Collet Chuck using the Metric threading table and new gears. Works great and I use it all of the time.

Finished internal taper


Test Fit Collett. Perfect fit.


Single Point M50x1.5 Threads


1/2" Collett, stock and new nut tightened on chuck. Holds great, no runout.