What The World's Been Waiting For - Yet Another Power Drawbar Design

[cncmill70]

Thanks again Ray! I think I will give it a try. Do you have plans available for your design or for sale? I don't know how to keep the disc springs from applying force on the on the bearings. That is my main concern for starting this project.

[HimyKabibble]

I have a partial set of drawings, but they would require some "interpretation" to be intelligible.  The really hard part is containing the bellevilles, and keeping them, and their container, concentric and balanced.  I never did quite accomplish that, which is another reason to abandon that approach.  Honestly, I would look into the stepper/planetary gear solution. I think it's simpler, more flexible, and presents fewer difficult design challenges.

Regards,
Ray L.

[Chestermarine]

Hello Ray:
Are you familiar with the "Universal Houdaille Kwik-Switch 200" tool holder, and BP spindle replacement?

I have two of them; one is installed on a manual BP clone, and the other is on a large Lagun mill, 40 taper spindle, with CNC. You can change tools by hand (no wrench required) in about 6 or 8 seconds. The spindle must have a brake, and you can change the tool holder with one hand.

My third mill is a bed-type CNC with a 16 pocket carousel tool changer.  The tool holders are BT-40. Back when I bought tooling for that mill, 1990, I was able to get BT-40 tool holders with the Universal Houdaille collet taper bore/lock nut arrangement.  This enables me to utilize the same collets and nuts on all three machines. 

Of course, you get absolute repeatable Z axis offsets for all your tools.

The tool holders are positive drive with two drive tangs on the body, and they have three style collets.
(1)Acra-flex, which has a small range in tool shank diameter
(2)Acra-mill super high precision, which takes the exact tool diameter without an internal drive plug.
(3)Acra-grip, same style and precision as (2), but has a spring-loaded plug, which drops into the mill cutter flat giving a positive, no-slip drive to the end mill for heavy milling.

The down side to all this is, Universal Houdaille went out of business back in the 80's, due to the insane Wall St. leveraged buy-out swindle (Investment bankers call it good business!).

There are companies making collets and other parts. There are also new and used Universal Houdaille collets and parts on E-bay.

I just looked on E-bay, and they have a good condition BP clone spindle for sale, and loads of collets, and tool holders.

I consider changing over to the Kwik-switch 200 system one of my best investments in tooling.

Regards,
John

[poppabear]

Hey Ray,

   This is exactly the issues I ran into when I was doing a prototype ATC for tormach waayy back...... 
I was asked on the cnczone that my holder had to be able to hold an r-8 with it doing a 1" DOC with a 1/2" roughing endmill though AL..........  "Like thier vids show for thier NON-atc machines doing....."  They where unwilling to invest the capital needed to get the ATC to that level, and they wanted me to keep the price under 3k.........  it is funny almost 3 years later they come out with an ATC/Draw bar that cost far, far more than that........  and I STILL have not seen that machine cut the 1" AL bar like I was asked to do....

scott

[BR549]

Take a look at the work Dave Decaussin has doon with the R8 spindles and an ATC with claw release. He uses a modified version the cat30 holder.

There are some vids on YouTUbe

(;-) TP