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Author Topic: BT30 spindle from scratch - with power drawbar and ATC of course  (Read 408528 times)

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Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #160 on: September 22, 2012, 03:46:04 PM »
Jeez! It would save time if I just post the drawings and get 'approval' before building the parts . . . LOL!

Offline BR549

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #161 on: September 22, 2012, 04:12:30 PM »
I have my RED pencil ready. LOL

(;-) TP

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #162 on: September 22, 2012, 04:39:39 PM »
I am just surprised it took you so long to come to that conclusion ;D

Hood

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #163 on: September 22, 2012, 05:15:28 PM »
Hood, do you know the spring pressure on those tool carriers? If not then the cyl dia and psi would be enough.

I found a spring that will fit the pods.  As installed would be 45lb closed 72lbs open. Seems like plenty, but would be nice to have real world confirm. Probably the heaviest too I would ever have in there would be only a few pounds, and there is a positive mechanical lock preventing the gripper from moving until the claw grabs it. The claw releases the mechanical interlock after it has the adapter by the groove. Only then can the air cyl move the gripper to release the tool. 

Thx.

Anyone,     I did all of the calculations on the drawbar gripper, but I don't think I need to do any of that for these little guys. I'm not planning to use a sleeve or to harden anything. Just 2 steel balls running right on the 7075-T7 body and held in a 12L14 ball holder should last years I would think.

Offline Hood

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #164 on: September 22, 2012, 05:33:55 PM »
Well I am going through to see the Chiron tomorrow so I will measure the cylinder Dia (  if I remember ;) 
Really though all you need is enough pressure that you cant easily pull it out or it rattle out with vibration so I wouldnt imagine it would have to be seriously strong.
Hood
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #165 on: September 23, 2012, 02:11:04 AM »
REMOVE THIS POST




« Last Edit: September 23, 2012, 02:23:56 AM by DWalsh62 »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #166 on: September 23, 2012, 02:17:53 AM »
While I admire where this has gone and found some of the conversation enlightening, the chances of anyone else getting a working spindle at a reasonable price doesn't look possible and it's a shame becuase I think you've really hit on somehting good.

I kind of consider myself a spindle aficionado, I have the luxury of working with a spindle expert who does this as part of his daily routine and I've gotten pretty good at it.

Here is some of my recent work on ATC spindles, what I started last week is an advanced version of the BT15 spindle cartridge with the disc springs internal and should be done in a couple of weeks.

Yes, even a sherline BT15 ATC conversion happened in the process which consists of a shaft, petal-clamp, disc springs and drawbar utilizing timing belt/pulleys and has sufficient tool clamping force to prevent slipping at 382lbs of pulling force.

As you can see in one of the pictures, they are real petal-clamps, nitride coated for strength and durability (over-kill, I found out).

I'm fighting with some Delta VFD's at the moment (I can't figure out how to make them do orientation) but as soon as I'm done I'd like to take what I've collected here and come up with a BT30 spindle cartridge that people can buy if we can figure out what a reasonable/fair price is I should be able to have something to purchase in about 30 days.

I do have a spindle expert at my disposal and I've made several different designs myself as well as a couple of BT30 spindles that were expensive but I believe I can produce something at a reasonable price based on the cumulative experiences and knowledge.
« Last Edit: September 23, 2012, 02:25:52 AM by DWalsh62 »
Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #167 on: September 23, 2012, 03:26:23 AM »
Here is a quick basic image of a design with good characteristics, the mounting flange can be located anywhere on the body and isn't currently shown because I'm not sure what placement would be better suited for most applications and running off 25pcs in various locations would be costly and time consuming for a production run.

Typically the two dogs are made from 42Cr with a hardness of HRC50-55 but most people use 4140 without hardening and I've heard little in the way of distortion or wear due to usage.

If not the image, here's a drawing that shows another design that can be produced for a reasonable price.
« Last Edit: September 23, 2012, 03:36:08 AM by DWalsh62 »

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #168 on: September 23, 2012, 10:57:16 AM »
Poking around for BT30 stuff and came across this complete spindle and actuator. Good comp.

http://www.ebay.com/itm/BT-30-8-000-RPM-SPINDLE-with-AIR-CYLINDER-ASSEMBLY-/300743758615?pt=LH_DefaultDomain_0&hash=item4605b99317

DWalsh: caution about posting drawings . . . the teacher has a big RED pencil  . . .  a corner chair with dunce cap . . .  and possibly a wooden ruler  . .  and a paddle  :o

Offline simpson36

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Re: BT30 spindle from scratch - with power drawbar and ATC of course
« Reply #169 on: September 23, 2012, 11:17:07 AM »
Another BT30 spindle  . . this one in need of TLC, but the price is right . . . .


http://www.ebay.com/itm/150874092526?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649