[SCzEngrgGroup]

I'm trying to make sense out of the pictures of the manual drawbar.

Ray, I hope I haven't made things more confusing.

The motor drive is mounted to the spindle enclosure, on a platform above the spindle attached by a post to the 1100 motor base and into a slotted holder attached to the sheet metal shroud. The drive screw is suspended above the hydraulic actuator of the LOD, and pushes down on it when actuated. There is nothing that clamps around or supports the bottom of the hydraulic actuator - the actuator rests only on the top of the spindle. The motor drive pushes the hydraulic LOD assembly against the spindle. The pressure required and the effect on bearings was a concern I had.

Earlier in this thread, Scott M and others explained that the 2500 lb force is exerted against the top of the actuator, and that the spindle bearings see only the roughly 300 lb drive force. I think that must be so, since the linear actuator I used is unable by itself to compress the washer stack. It claims only 900 lb of force.

Chris D
You're entirely welcome, and I hope this is useful either as a take-off point for a better design or as it stands. Incidentally- I think one could, if one wanted to be very finicky, build it without the latching relays, using the cam and an extra two microswitches. The relay approach seemed to me to be about the same cost and easier to implement, as one of my design goals was low-precision.

glc

That can't be....

If nothing is restraining the hydraulic cylinder, whatever force the cam is exerting downward on the piston can only be passed through to the spindle, without amplification. It cannot have a small down-force exerted by the cam mechanism, and the large upward reaction force from the spring stack, without some additional source for down-force to balance the difference in those two forces.

And, whatever down-force is being applied to the spindle can ONLY be resisted by the bearings, if there is nothing else supporting the spindle, which I don't see in the photos. The only way to avoid putting the full release force on the spindle bearings is if there is something on the drawbar that provides up-force to the spindle, to counter-act the down-force applied by the hydraulic cylinder, and take the load away from the bearings.

That's all basic physics. So, it doesn't make sense on several fronts.

How is the hydraulic cylinder actually mounted onto the spindle?

Regards,
Ray L.

[GLCarlson]

I looked at my pictures again.

If I'm looking at the right picture, the bracket Ray L. is referring to is the Tormach spindle lock assembly, which is shown engaged (of course, it never would be with the LOD). That's part number 26 in the spindle/head drawing of the series II 1100.

Scott M's original design removed the manual lock and modified the motor base lock support. My implementation leaves it in place. For reasons now unknown, when I shot that picture, I showed the spindle lock engaged. That's confusing and wrong.

(Thanks for catching this, Ray)

glc

[SCzEngrgGroup]

I looked at my pictures again.

If I'm looking at the right picture, the bracket Ray L. is referring to is the Tormach spindle lock assembly, which is shown engaged (of course, it never would be with the LOD). That's part number 26 in the spindle/head drawing of the series II 1100.

Scott M's original design removed the manual lock and modified the motor base lock support. My implementation leaves it in place. For reasons now unknown, when I shot that picture, I showed the spindle lock engaged. That's confusing and wrong.

(Thanks for catching this, Ray)

glc

Does the spindle have flats, to accommodate the spindle lock? If so, does the hydraulic cylinder somehow make use of those flats? That would resolve my confusion.

How is the cylinder installed on the spindle?

Regards,
Ray L.

[GLCarlson]

Ray,

I'm a chemist. I'm forbidden by the rules of the guild to do physics!

I had the same concerns. I can tell you that the LOD actuator (the cylinder and drawbar) just drops into the spindle and sits there. Without a collet in the bottom of the spindle, it rattles around.

Earlier in this thread, there was some discussion about how the LOD works - others concluded that the force of the stack was exerted against the top of the LOD, not on the spindle bearings. I tried diagramming the forces, and that appears to be a reasonable explanation- so I built the LOD actuator, and it performs as Scott M claimed. Tormach has accepted the LOD as an approved mod, so whether its 300 lb or 2400, Tormach is OK with it. I'm not enough of a vector mechanic to attempt a publishable force drawing, so I can't help further.

In this case, I'm with Galileo: "it still moves". However it does.

glc

[Scott_M]

Hi Ray
With regards to my design...The lever and cam generate about 350-400 lbs of downforce against the top of the hyd. actuator , this force is applied directly and transfered to the spindle bearings. The Belleville spring stack is inside of the actuator body and the cap is the hydraulic unit. The cap and body are threaded together and it is this threaded connection that is resisting the additional force. The 2400 lbs is trying to separate the cap from the body but can't, so it compresses the Belleville's instead and pushes the drawbar down.

I hope that explains it for you

Scott

[SCzEngrgGroup]

Hi Ray
With regards to my design...The lever and cam generate about 350-400 lbs of downforce against the top of the hyd. actuator , this force is applied directly and transfered to the spindle bearings. The Belleville spring stack is inside of the actuator body and the cap is the hydraulic unit. The cap and body are threaded together and it is this threaded connection that is resisting the additional force. The 2400 lbs is trying to separate the cap from the body but can't, so it compresses the Belleville's instead and pushes the drawbar down.

I hope that explains it for you

Scott

Scott,

OK, that clears it up. I didn't realize the Bellevilles were inside the LOD. Now it makes sense.

Thanks!

Regards,
Ray L.

[Vogavt]

Scott
I looked for the LOD page on your website but couldn't find it. I'm getting the "not found" error message.

Do you still sell the plans?

[Scott_M]

It should be here http://www.sdmfabricating.com/LOD.html

It works for me.

Scott

[Vogavt]

Got it. I couldn't find a link from your homepage but may have overlooked it. Thanks!

Sent from my DROID RAZR using Tapatalk 2

[michaeleverson]

Is this complete system offered as a bolt in kit anywhere? I am considering buying a pneumatic draw bar, but I like this better.
Mike

[native34]

How much for just the plans for the Multiplier? I have a Charter Oaks Machine, and I will be building a auto change tool system for it. I would like to incorporate your multiplier to save me some time designing a whole new system if I have to.