Rolling Mill

[Ralphxyz]

My "normal operation would be to elevate the mill only 1/4". It is reasonable steady but depending on the position of the casters can get shaky, but cannot fall over.

I was only extending the scissors because I had a request to see them extended. Obviously I did not "think" it through but just started cranking.

I diffidently would extend the lower channel iron if I were ever to need to raise the mill more than 1/4".

And thanks again everyone for your comments, I do hope this thread might help someone avoid killing themselves.

Ralph

[IAMSatisfied]

fixit45 made a point well worth repeating here:

"... looking at your photos you were trying to balance the whole machine on two unstable points, scissor jacks do not have lateral stability."

If you go back to Ralph's first photo on page two, you'll notice that the top and bottom channels ARE NOT PARALLEL, and it's that pressed sheet metal scissor jack with punched gear-lobes that failed to keep things stable (picture a SLINKY or coil spring in place of the scissor jack)... in this case, I don't think a wider stance on the wheels would have saved the day. I've seen those gear-lobes splay and fail when overloaded or loaded on slope... they just give me the willies.

Automotive scissor jacks are hardly suitable for lifting a static load on perfectly level ground, but certainly NOT a dynamic load. I despise how cheaply made these jacks are and am very aware and respectful when I'm constrained to use one to change a tire.

Ralph, I'm sure glad you were on the fortunate side of this lesson.

[Ralphxyz]

Well I finally got the stuck MT2 shank free from my spindle.

I tried beating on it, used my rotary hammer, drove a wedge between the spindle and the shank but nothing worked.

finally I came across this thread of using a screw jack this worked!!

I tightened down on a Class 8 9/16" bolt as tight as I could with a 10" wrench, I'll tell you if the bolt had been a class 5 or less it would have sheared.

As I was tightening it with all that I had there was a loud "CRACK" and the shank was free!!

This was a tough one, thankfully I found that Madmodder thread.

If you want to see some pictures of the screwjack they are on my website.

Thanks for all of the help and encouragement, this really had me down.

Ralph

[Frank S]

Glad you got it it out. Now that that is over with get yourself another arbor of use a couple of MT 2 drills with some inspection die of your choice check them against the spindle taper. there was some reason it was jamed so tight. Possibly you may have over tightened the draw bolt . of what ever machining operation you did previously may have had a lot of vertical chatter which could act like a percussion hammer driving the arbor up into the spindle, no matter what the cause for peace of mind you should try hard to learn what it was so you can prevent it form happening again

[Toolmaker51]

Glad you got it it out. Now that that is over with get yourself another arbor of use a couple of MT 2 drills with some inspection die of your choice check them against the spindle taper. there was some reason it was jamed so tight. Possibly you may have over tightened the draw bolt . of what ever machining operation you did previously may have had a lot of vertical chatter which could act like a percussion hammer driving the arbor up into the spindle, no matter what the cause for peace of mind you should try hard to learn what it was so you can prevent it form happening again

Ditto. Frank S nailed it. Morse tapers are incredibly secure 'self-holding' variety of tapers. I can't justify why #1 through larger are not consistent in taper per foot. I suspect the formula was based on surface area, where larger sizes didn't need length to ensure engagement. But the threaded jack was best solution by far, threads generate leverage exactly like an inclined plane. The large members of machinery leveling pads prove it. And lathe tailstocks...