4th Axis Build

JimDawson

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A few months ago I picked up an unused 6 inch Vertex Super Spacer almost free. Cost me about $80 in materials and a couple hours labor. :)

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But this is about powering it up.

The job that I got it for finally is ready to go so now I need the 4th axis on my machine. The goal here is to install the stepper drive without modifying the original hardware. What I came up with is clamping the assembly onto the cam support shaft. That way I can just remove it and am back to normal operation.

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The concept drawing

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So first operation is to square up the 1x4 aluminum. Then drill the cap screw holes in the housing. This is so can bolt the cap in place later without disturbing the setup when ready for that operation. These are just drilled for tap size, but will be tapped later.

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Then drill the cap and counter bore to depth for the cap screws. The depth of the counter bores are set so that in subsequent operations, the end mill will not hit the cap screws.

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The first operation was to cut the pocket for the cap, once that was done, then the holes were tapped and the cap bolted into place. Then the various pocketing operation were done on the entire motor side.

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And the completed motor side operations

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And the pocketing is complete on the belt side.

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The pocketing is complete on the belt cover. Tapping the 1 inch -32 hole for the shaft cover. Why did I use a 1-32? Because I had a tap for that, it’s a standard C-mount lens size. Here I’m using a 3/8 tap as the center point to keep the tap on center. Keep down pressure on the quill while turning the tap. (the quill is vertical, I was just holding the camera at an angle)

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And the almost completed pieces. Now the outside profile needs to be done.

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Setting the zero to the center of the T-slot, I just use a ½ inch cap screw in the chuck to get pretty close. Does not need to be dead on.

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First anchor one side of the motor mount down to the table with a chunk of MDF board under.

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Now indicate the side to align it to the table. I used the Blake because it will be used in the next operation.

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Next is locate the clamp hole. All of the features are relative to this location. This is located at -6.115,-2.000

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Now bolt down the belt cover. I am using a feeler gauge under the bolt to make sure it does not bottom in the T-slot.

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I had to change to washers under the bolt rather than the clamp. The collet nose would have hit the clamp. There is a thread on H-M about using a mill as a band saw, well that’s kinda what I am doing here. I could have trimmed these on the band saw, but I got lazy, just press go and come back when it’s done.

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Getting close

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Corner rounding the edge with a Harbor Freight carbide router bit.

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The motor mount ready to ready to install

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And the motor is mounted

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The trained monkeys pulled the wrong pulley for the 3/8 wide belt order, so I just pulled the front flange off. :mad: The belt won’t come off, the bottom flange will hold it.

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And the belt and pulleys installed.

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Has a bit of a snout sticking out, need to cover that. A handle can be installed for hand operation with the motor installed.

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I made the shaft cover from 1.125 aluminum bar stock. Since the thread length is only 3/8 inch and it’s to a shoulder, I turned the tool up side down and ran the lathe backwards. I did the threading at 460 RPM. Made nice threads.

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Fits nice but maybe it’s a bit long. We can call it Pinocchio:adore:

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Corner rounding on the lathe, another HF carbide router bit. Work back & forth between the edges, don’t try to take a full width cut, it’s not stable enough.

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The face wasn’t planned, but its kind of cute.:grin:

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The assembly can be used both horizontally as well as vertical just by loosening the cap screws and rotating around.

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Next is to install the drive and then write the software. That may get done tomorrow. I'll post pictures of it actually being used pretty quick.
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Beautiful execution, well done.

CHuck the grumpy old guy
 
Just an update, I now have it running under computer control. G-code control to follow soon. 3,600,000 steps per 360 degrees of rotation or 10000 steps per degree. Way too fine resolution to be really useful, but it's kinda cool. At max speed, the table rotates at 80 degrees per second.
 
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Thank you all for the kind words.:) I hope you all enjoy these projects, and more importantly are able to take away something useful to you.

Other than the obvious bragging about my creations :rolleyes:, I post these threads showing not only the what but also the why I did something the way I did. I also try to show work holding, tool use, order of operation and overall process. Where appropriate, I will also post the stuff that didn't work so others don't make the same mistakes.

If a project has more than a couple of operations, I will ''machine'' the entire project in my head prior to ever making a chip. Sometimes It's back to the drawing board because something is too difficult to machine, or will have conflicting operations. This is especially important when doing CNC work.

Hopefully I can also pass on some of how to think through a problem and find a solution that both works and won't break the bank in execution. Problem solving is a learned skill IMHO, and I hope some can gain some insight into my approach. This is not to say that the way I do things is the best or ''correct'' way, but rather just to illustrate how I did it with what I have to work with.
 
Holy carp! I was impressed with just the get - then ya done that. Very nicely done.
 
IT'S ALIVE!!! Not too bad, I designed the drive last Sunday, ordered the parts on Monday, and am making chips with it on Saturday.

I made the first test cut tonight. It came out OK, but I need to work on the feed speeds a bit and smooth out the programming. I'm still learning how to use it

Sorry for the crappy video quality. I see now that I should have moved the camera closer in, not used so much zoom, and used better lighting..

I ordered a Grizzly tailstock and a carbide tipped center for it. I knew the tailstock was going to be a bit tall, but I wanted the heaver unit. I also found out that the keyslot in the bottom is not square to the face, about 0.040 off over the length. :burned up: No problem, I figured out a quick work around.!

This is the lowest position of the tailstock with out modification. About 1/4 inch too high.

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The slide slot needed to be a bit longer, so I went another 0.375 more. Mounted to the angle plate. This may be the first picture you have ever seen of my mill when it wasn't buried in aluminum chips.:grin:

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Here is how I supported the other end
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And the setup.

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Oh, almost forgot, here is a screen shot of the new screen with the rotary axis installed.
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Very nice. I have no idea what I'd do with that screen...where's the GO button? :)
 
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