RF-30 Clone Head Alignment Guide

Let me know how you like the upgrade. It made my mill nicer to use.
 
@Gravydog I'm planning to do your alignment upgrade. You mentioned that the joints you ordered had a lot of play. I'm looking at these Heim joints. Curious if you think they are up to the task.
Thanks!
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I don't know but in the photo they look like better quality with the bronze insert than the ones I bought. I'm often sorry when I put price above all else. They will never see a heavy load or wear from lots of movement, so if there is no discernible play in them they should work great. Good luck with the upgrade.

Rob
 
Gravydog said:
I don't know but in the photo they look like better quality with the bronze insert than the ones I bought. I'm often sorry when I put price above all else. They will never see a heavy load or wear from lots of movement, so if there is no discernible play in them they should work great. Good luck with the upgrade.

Rob
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Thanks Rob. I think I’ll go ahead and order them.


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Garryloy said:
Good observation. I planned to add holes for cooling air in case I ever dropped the head all the way down.

I bought a 24" length of a 2" wide, .090" thick, 1/4" pin continuous hinge from McMaster Carr. Cut it into the three sections I needed. Drove out the pins, used a Bosch carbide tooth oscillating blade to cut 1/16" out of the knuckle tab so I could crimp it tighter around the pin (before pin insertion to allow for springback). I also added a very strong compression spring to bias the lateral play out of the hinge (see model). I have them all finished, drilled and countersunk ready to install. They are so stiff you can barely open them by hand. I believe the hinge idea would not work without these modifications. If I had it to do over I would seriously consider a fabricated pivot joint, but it could not be as compact. So far my fabrication is 100% per the 3D model shown. I really like the rod ends design. But, I found the cheaper ones to have some play. I know you can get them with a permanent lube liner that will preload them.

Another design consideration was anchoring the top hinge to the head without interfering with the casting movement during clamping and unclamping from the column. The angle iron brackets are attached only to the front area of the head.

Not part of this thread, but you can see my next project. Hand operated toggle clamps on the side with the crank to lock and unlock the head without tools. I will prototype this before full project commitment since it is unproven. From an engineering point of view it looks good on paper.
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@Garryloy , did you ever finish this head guide? This looks like it would be the easiest and most accurate installation I've seen, and I'd like to give it a go.

-Did it work well?
-How did you guarantee and then verify alignment? (It seems that if you get the angles of the hinges off even slightly, it would spin the head as it came down.)

I like what you suggested for removing axial play in the hinges. I would add substituting a bolt for the hinge pin. Tighten the bolt to push the fingers together to remove any lateral play. I'd also use some 4" wide stock I have. It won't interfere with airflow that way. And, because all the forces, what there is of them, will be in shear across the flat, that should be plenty wide.

I'd also flip the bottom hinge and screw it to the column base. Screws would have to come out to rotate the head, but that would be such a rare event anyway.

The final thing I'd like to try is having different lengths for the sections. If the bottom were just slightly shorter than the top, the leafs would droop down as the head approached the bottom.
 
Re-reading the whole thread, I happened to notice something about the 4 pulley speed chart. It seems to be missing 6 additional possibilities ... 4-7-10, 3-5-9, 3-5-10, 3-6-10, 2-5-10, and 1-6-9. Are they (close to) redundant with some other combinations?
 
Shotgun,
Thanks for your comments. I have not finished and installed the hinge guide. I have a great excuse but I will spare you the gory details. I expect to finish it within the next two months. I am excited about it since I have done a lot of engineering analysis and design work on it (I am a retired mechanical engineer), and 90% of the parts are finished.

You are correct about the alignment. I am counting on precision machine work, and I won't know how good it works until I test it. Theoretically it is perfect. (Ha!)

My hinges are ready to install and they are too tight to operate by hand. This is good.

I wanted it to work with the head rotated, so the column clamp mount is necessary. The clamp is 1/2" thick plate.

My hinge plate sizes were chosen to give the lowest possible head position, which is important to me. They are 7-1/2" wide, which works out great for buying one 24" hinge.

The only part not finished is the head bracket. This is a weldment that must be screwed to the front half in order for the head clamping system to work.

Your ideas will probably work fine. All designs are usually a selection of compromises. Another way to say there's more than one way to skin a cat.
 
Garryloy said:
My hinge plate sizes were chosen to give the lowest possible head position, which is important to me. They are 7-1/2" wide, which works out great for buying one 24" hinge.

The only part not finished is the head bracket. This is a weldment that must be screwed to the front half in order for the head clamping system to work.
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Could you maybe start another thread, so we don't hi-jack this one? I'd really like to get more details before I start on a version of this, especially the "head clamping system". I'm in no rush, as I'm knee deep in the Dividing Head Group Project, and I'm behind.

As for the plate dimensions, consider what would happen if reduced how far the bottom plate sticks out the back by the thickness of the plate and moved the head attachment point back by the same amount. As the head moves down, and the guide folds, the middle hinge will be forced to move down as well as back. It will move away from the motor, and not stick out as far.
 
I wonder if Gravydog would mind if the different mods to his original design were continued on here?

Its getting harder and harder to find specific threads because of the sheer mass of info on this site.
 
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