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Design Advice for Spindle Features
I have a very good idea of the type of work, design envelope, and level of precision I'd like to get out of my bench top slant-bed lathe project. For the most part it would be collet-work in the 1-2" diameter 6" length range, so I figured 5C would be the best taper/bore for the spindle, with an external manual closer at the opposite end. But since I already have a bunch of accessories for my manual lathe with D1-4 cam-lock spindle, and because I could physically *fit* a cam-lock flange onto the front of the spindle shaft, I included that feature in my initial design.
I haven't used a CNC lathe for anything before; am I actually going to find much use for the D1-4 capability? My thinking is that since the workspace is enclosed, it will be at best awkward to access chucks for gripping/ungripping let alone swapping them out, at worst I think some of my larger accessories like a 10" face plate won't even fit through the door. Plus, with a top speed of 4000rpm, I believe that the machine is capable of exceeding their rating (while I wouldn't do so intentionally, all it'd take is a failed encoder or bad code to have a possible grenade on my hands). Lastly, I think the 5C-sized 1.38" bore would prove limiting enough to reduce the utility of the chucks to hold odd-shaped items. Ditching the D1-4 flange would also allow my collets to sit about 2" closer to the bearings.
Unless the small 5C-arbor 3/4 jaw chucks out there too terrible to even consider for the occasional job, I'm just not seeing what I'd be missing by forgoing the added cost/size of D1-4 functionality at the spindle. Am I forgetting something important that I'd immediately regret the first time I fire up the machine to turn a part?
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Re: Design Advice for Spindle Features
Over a hundred views and no one has an opinion? Inconceivable.
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Re: Design Advice for Spindle Features
Unless you are really looking for the challenge of building your own spindle (I can respect that!), you may be well ahead for your build to buy an older Hardinge small lathe (a DV-59 variant, for example), and build that into your system. They have wonderfully accurate spindles, and come with 5C collet capability built in. Usually they have a manual collet closer, as you mentioned above. You will see many of these lathes in the $1000-$2000 range, especially on ebay or Kijiji. I would expect that you would end up paying at least that in building your own spindle. Since you will be making it into a CNC lathe anyway, you won't need one that comes with lots of accessories, which can definitely lower the cost to buy.
If you want to add a chuck, these lathes have either a 4 degree Hardinge spindle nose, or a threaded 2-3/8"-10 spindle nose. The 4 degree taper nose is the better choice if you want to do much with reverse in your work - it won't unscrew and fall off if you reverse too fast.
HTH.
That spindle, or the even closer Emco 10, are largely what I'm going for. The Dunham Tool spindles are almost exactly what I'm seeking. All are a bit too expensive, especially the Dunham. 5C bore, six inch spindle length, proper bearing package (dual paired AC and deep groove). Top RPM of at least 4000 is also hard for the older machines to meet.Originally Posted by DSpeck
My question is whether it is worth adding D1-4 to the feature list for a small enclosed CNC lathe, since it seems distinctly advantageous for larger manual lathes doing mainly chuck work.
