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View Full Version : Atlas 12" lathe (Secondary headstock for larger diameter turning)



Mike Hall
02-26-2015, 02:52 PM
I had been trying to figure out how to do some machining on some cast aluminum motorcycle wheels which are about 19" in diameter. Well, the only solution i could come up with for doing the work myself would be to device some means of tuning a 20" object on my Atlas 12" lathe. The idea was to build a secondary headstock which will be driven with the lathe motor through pullies and a V belt. Here is a simple drawing of what I have in mind for turning these aluminum wheels. I will also make a robust tool holder spacer which is the area i think i would run into issue with if at all. I know the forces on the cross slide will be compounded with the tool being mounted an additional 4" above normal tool height but, with light cutting in aluminum i should be ok i would think. All the machine work i need to do is in the hub area for adapting some non shaft drive wheels to work with a shaft drive motorcycle. I believe with light cutting i should not run into any issue with such an idea. Anyone want to chime in on this idea? Myfordboy on youtube did something similar on his little lathe so hopefully i can get this working well enough to be able to machine some of these wheels.

Thanks
Mike

http://i239.photobucket.com/albums/ff248/Mhall222/Atlas%20secondary%20headstock_zpsngkkb0k1.jpg (http://s239.photobucket.com/user/Mhall222/media/Atlas%20secondary%20headstock_zpsngkkb0k1.jpg.html )

dp
02-26-2015, 03:08 PM
None are shown but gussets would be an imperative inclusion. It will also be important to pay attention to the SFM numbers. Finally, make sure the lathe is securely bolted down.

jep24601
02-26-2015, 03:33 PM
If the v-belt pulley is in a morse collet you will get the secondary headstock much closer to the hold down base (it extends further to the right than you show) and reduce the twisting in the ways which might result from this operation. Also you could gear down the speed with appropriately sized pulleys.

Rosco-P
02-26-2015, 03:40 PM
4" riser block under the headstock and cross slide wouldn't be easier, quicker and cheaper than building a taller headstock?

CCWKen
02-26-2015, 04:06 PM
You'll need more than 4". 6+4=10 or a 20" swing. You'll need some extra for clearance. But that's not the problem. You'll never be able to get to the outer 4+" without more cross travel too. That means a new carriage. You might give some thought to building a vertical lathe. Perhaps using a shop press as a starting point. Mine has at least 30" between the posts.

lbender
02-26-2015, 04:18 PM
You might give some thought to building a vertical lathe.

If you have a vertical mill and a rotary table, you can fashion something like a Bullard lathe with live tooling.

Doozer
02-26-2015, 04:57 PM
Q?
What do you suppose is the reason no manufacturer has ever made a 20" lathe
with the same size proportions and weight as the 10" Atlas?
I don't think you could even turn wood successfully on a lathe of such proportions.
Might be best suited with a 18" rotary table on a Bridgeport mill, assuming you
choose not to have a proper size lathe.

-D

firbikrhd1
02-26-2015, 05:23 PM
A company called Globe made milling heads for lathes much like the one you describe. I have one and posted using it as you describe some time ago. Here is the link to my post.

http://bbs.homeshopmachinist.net/threads/47856-Increasing-the-capacity-of-a-small-lathe?highlight=globe+milling

You can search Globe Milling Head on You Tube and other places and find additional info.

You might find this post (no vested interest) interesting: http://castboolits.gunloads.com/showthread.php?269749-Globe-Milling-Attachment-for-Atlas-Lathe

The concept works within limits. Don't expect to be able to sue your Atlas like you would a 20 inch lathe, but if used with care for the occasional project it will work fine.

jep24601
02-26-2015, 05:52 PM
You'll need more than 4". 6+4=10 or a 20" swing. You'll need some extra for clearance. But that's not the problem. You'll never be able to get to the outer 4+" without more cross travel too. That means a new carriage....

You would have all the travel you need if the operations were confined to the rim. Your tool would have to be properly angled of course.

boslab
02-26-2015, 06:52 PM
It does sound like acquiring a bigger machine would be the best, we did have a little vertical in work, I loved it, I'm not sure if verticals are called lathes or boring machines as I've been corrected in both directions, they were going to get rid of it as it was too small for most jobs, it went in the scrap bin a month after I left I was told, assholes.
You do need a heavy machine if you have 2 foot dia spinning, only my humble opinion, safer.
However your design is novel, but your going to be hanging out the window with the tool as has been mentioned, prepare for chatter if you can get there
Mark

Mike Hall
02-26-2015, 06:58 PM
Thanks for the replys, I know the lathe would not be usable for much other than light aluminum cutting at most. The lathe is a 12" Atlas so it has 6" from center of spindle to bed and if i add 4" I will have 10" so that would create a 20" swing. I really do not think there would be huge issues with the use of an extended extra headstock but I do think the cross slide and tool holder may flex more than desired with the needed extensions. I am a major DIY guy and have done everything myself sense I was a kid and if i can utilize my Lathe to turn a few wheel hubs for a project that would be pleasing.

I will have a mill someday and I agree a rotary table would be ideal for what I need to do. I thought about getting a Grizzly compound table and make a stand along wheel maching Mill but, that is just another options i could explore. I really do not want a whole another machine if i can have a attachment for my lathe that will get the job done. I am not doing production work or planning to do wheels all the time, i just want to be able to modify a few sets of wheels and thats all for now.

This is the model lathe I have. Its a Craftsman Commercial series 12" built by atlas. http://www.lathes.co.uk/craftsman/page3.html

Mike Hall
02-26-2015, 07:00 PM
All the machine work I need to do is confined to the center hub of the wheels. I would not have to do any work outside of 7" or so. The wheels are cast aluminum KZ750 wheels that I am going to adapt to work on a shaft drive motorcycle.

Mike Hall
02-26-2015, 07:03 PM
https://www.youtube.com/watch?v=2ivuCRavE8I

This is a little more involved than what I wanted to do. I figured a good V belt would be good enough and easier to setup.

Gary Paine
02-26-2015, 08:32 PM
Mike, there is always a way. I do not know what kind of machining you are needing to do, or with what precision. I will say that I have done some turning of aluminum with what amounts to a very large graver tool. Like a wood lathe chisel.
That said, I have done outboard turning on an Atlas 10 inch with success. I moved my heavy floor model drill press to the outboard end of the lathe and mounted a tool rest on the table. I do not think I even anchored the machines together. Light cuts worked well. To pull this off, you will need to fab up a drawbar and rig a faceplate to fit the bore of the spindle.
Worked for a round hardwood table top. Probably for aluminum as well.

J Tiers
02-26-2015, 09:51 PM
Logan made an accessory for the 11" machine, which made it a 16". Essentially exactly what you propose, so your idea has the merit of manufacturer support! Raising blocks for tailstock and compound completed the Logan setup.

Mike Hall
02-26-2015, 10:00 PM
Thanks for that detail about the Logan lathe. I found this which is what I want to do but, again rather than gears use belts.

http://i239.photobucket.com/albums/ff248/Mhall222/missing-image.png_zpsbgn2qqrq.jpeg (http://s239.photobucket.com/user/Mhall222/media/missing-image.png_zpsbgn2qqrq.jpeg.html)

Mike Hall
02-26-2015, 10:09 PM
I sure wish i could find a nice simple casting like that to build my headstock with. I have yet to find anything cheap that I could utilize as a good base for the headstock build. Anyone have any ideas?

Gary Paine
02-26-2015, 10:16 PM
What are you going to need in the way of a spindle? Chuck? Faceplate?

I'm thinking a wheel hub. Cheap and great bearings. Mount on the heaviest block of stuff you have.

Mike Hall
02-26-2015, 10:21 PM
I too was thinking wheel hub and weld on axle for trailers. 2000lb hub with bearings and axle is like $30. Only reason why haven't gone with that idea yet is because of the narrow bearing spacing which even with the light duty machining may be more opt to move than if i had wider bearing spacing. Using off shelf parts with little modifications would be ideal but, i also want to make sure this is a nice attachment so i do not want to cut any corners. I found this bearing setup that would be nice but, i wouldnt mind finding one a little cheaper. http://www.ebay.com/itm/Dodge-Fan-and-Blower-Bearing-1-134132-/180564379630?pt=LH_DefaultDomain_0&hash=item2a0a79c7ee