Steady Rest

I got a bit more work done

First order of business was to fix my stupid measuring mistake. If you look at the picture, the bottom hangs over the base by 0.193 on each side but worse than that, it is also of center, so 0.013 off of one side and the rest of of the other. The worst part was that it would not fit between the carriage rails.
Double check the measurements before making chips, it will save a lot of work.:cussing:
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So back in the mill and make the modifications and try to make it look like it was supposed to be that way:rolleyes:
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OK it fits now and clears everything, but it looks like crap. :mad: This will haunt me every time I use this tool.

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OK enough whining.:faint:

On to the fingers.

First create a work surface. I was going to bolt down an aluminum plate the the table to mount the work on, but I found this chunk of 6'' aluminum channel in the miscellaneous stock rack, and I needed the vice for the next operations anyway. Had to remove the rear jaw to get it in there. Then of course when you tighten up on a piece of channel it wants to bow up in the center a bit, so a light facing cut to flatten it out.

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Then drill & tap the mounting holes. These will be used later.
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The work piece is 1/2 1018 cold rolled steel. I had to clamp the channel down also because it tried to pull up on me when I was tapping. The pilot holes are also drilled where the pocket start, much easier on the end mill. Even center cutting end mills don't really like plunge cutting. That's why drill bits were invented.;) For the moment the work is just clamped to the aluminum

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OK, the slots are cut and in the middle of the chamfering operation. I used a 1/4 inch, solid carbide router bit to do the slots. 2400 RPM, 10 IPM, 0.063 DOC. Made the slots 0.260 wide for bolt clearance.

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Here is the work screwed down. And starting the outside profile operation. Remember what I said earlier about end mills not liking plunge cutting? Well I should have drilled pilot holes because on the next pass after this picture the router bit shattered. It was plunging too fast. :( I guess I got pretty good life out of that one anyway, it had done all of the work on this entire project up to this point and a few others. Router bits are not quite as robust as end mills, the web is a bit thinner. But they cut great, are razor sharp, and available on a Saturday afternoon at your local big box store.

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The only sharp 1/4 inch end mill that I could fine was a HF 4 flute. It did the job but it won't run as fast as the carbide so I had to slow the feed down also. So about 90 minutes to cut these 3 pieces out, including the tool change.

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and the near finished parts with the bearing mount holes drilled, tapped, and reamed to depth.

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Now for the bearing clearance. Just lined them up in the vice, squared them up, and away we go:) Note the emory cloth between the movable jaw and the parts, grit side to the parts, that insures that nothing is going to move.

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And the slots complete. 3/16 cobalt, 2 flute. 10IPM 0.035 DOC, 1800 RPM. The slots are 0.520 deep to clear the 0.500 bearing. I would have used 0.750 bearings, but I had 0.500 in stock.
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And the completed fingers

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This will handle a full 4.5 diameter part in the lathe and go as small as about 1/8 inch.

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A little teaser for the next operations ;) Stay tuned!............

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The next operation is to pocket out the clearance for the clamp handle. I didn't want the clamp to protrude out like below

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So it gets buried back into the top. This is the one exception to plunging with an end mill. If you take small bites, less than about 20% of the end mill diameter, an end mill will plunge just fine. Using a 3/4 inch x 4 inch end mill and 0.063 step over, it took about 5 minutes to rough out the shape. Then go in and finish the profile to final dimension.

The following pictures are a little strange, I hit some button on my camera and managed to set it for using the flash all the time. For some reason they came out with a red tint, and with the flash the shutter speed is so fast that it ''stops'' the spindle. That is turning about 1200 RPM in this picture.

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Now for the bolt slot. A quick setup with a level. I leveled my mill so I could use a level for setups. This only needs to be close, it's just for bolt clearance. It doesn't need to be held to 4 decimal places, no point in chasing zeros when you don't need to. :confused: If a part needs to be held to 0.0001 then I'll get it there, but most work does not require extreme accuracy.

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And the finished part. All of the machining operations are done on the top.

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Now to cut the bolt clearance in the bottom. I did this in two setups. The reason I did this in two setups is so I could get a radiused end in both ends of the slot and I didn't have a 5/16 ball end mill that has a 0.75 depth of cut. So rotating 90° solves that issue, and I can make the same shape with a 0.300 DOC. I didn't get any pictures of the setup when cutting the slot in the top, but it was just clamped in the vice with the legs down. Then I rotated it 90° counterclockwise and squared the legs to the vice. Because of the shape of the work, I had to hang it out of the vice quite a ways so vibration will be an issue. To overcome this, I clamped an angle plate to the work to add mass. The angle plate is not bolted to the table, it just adds mass to the system.

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And nearly finished

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The next operation is to cut the clearance slot for the hinge. For this operation, a HF angle gauge is used, this thing is actually pretty accurate, and the operation does not require extreme accuracy, it's just clearance. First check the angle gauge to see if there is an offset needed, but it's reading right on 0 :)

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The work will be done on the right hand side and the work needs to be rotated 28° off of vertical so using the flat surface on the other side the angle can be set. It's the only surface that is parallel with the feet. I figured out how to reset the camera so the pictures are normal again.

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So how do you locate the work when there are no flat surfaces to work from? Well there is a nice reamed 0.375 hole with a known location, so stuff an end mill with a 0.374 shank in there and locate off of that.

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I am not happy with this setup and the slot shape that will be generated. I need to re-think this before I make chips. o_O That and I need to go get a couple more 1/4 inch router bits.;)

Stay tuned......More later! :)
 
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Thanks for posting the blow by blow account of your steady rest build and all the other useful tips & tricks that go into the process. Mike
 
OK, thinking is done and the options have been explored. I could spend a day and a half making up fixturing, writing G-code for the 4th axis, and setting up to make the Ideal Shape, or I can just cut the *&^^ slot an inch deep and do it the Easy Way. I would have had to build a 4 inch riser for the 4th axis, then build all the fixturing, would have been a project worthy of it's own thread. Not gonna happen! o_O Especially when the straight slot will work and I can get it done in about 15 minutes, setup, G-code and all.:oops:
All of this because I did not think through the design before making chips. :burned up::cussing: A little more thought and planning goes a long ways.

So here's what I'm going to do.

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OK, off to buy some router bits and run a few errands.

More later........:)
 
I hate to be the first to tell you, but sound travels 330 m/s or about 1075 ft/s at sea level. I always figure lightning is a little over a mile away if it takes five seconds.


Steve Shannon
 
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Well I can see the light at the end of the tunnel. This was supposed to be about a two day project but so far I'm into it about 10 days and still not quite done. But I may finish it later this evening, it's really time to get on to a couple of other projects.

First set up and cut the slot for the hinge. The big chunk of steel clamped on is just to add mass to to keep any chatter to a minimum because the work area is sticking so far out of the vice. I could have removed the vice and done this with an angle plate but I wanted the vice on for the next operation.

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And check the fit before tearing down the setup. The fit is good!

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And in the open position

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Now to drill and tap the base mounting holes. The dimensions have changed so many times on both the base and the bottom that I no longer know where the screw holes are relative to an edge. So the easiest way to locate the holes is to put the base on the bottom, line everything up, and transfer punch one hole. I know where the holes are relative to each other, just not to an edge. The holes in the base were drilled 1/64 oversize for bolt clearance so it has a little wiggle room.

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Then using the pointy end of the edge finder and a thumbnail it's easy to locate the transfer punch divot. If you can't catch a thumbnail on the edge finder in both the X and Y axis (both sides), then you are pretty close to center. The set your DRO to the location of that point, or if you don't have a DRO, that point becomes your zero.

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OK, drilled & tapped, and bolted into place. Where possible I drill & tap blind holes at least 1 inch deep, I hate bottoming out bolts. Also, I normally put the spindle in neutral, chuck up the tap, and run it in by hand a few threads. Then loosen the chuck and finish by hand tapping. I normally don't powertap over 1/2 inch deep.

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And there it is. Only one assembly left to build. The clamp bolt system. Won't take too long to build and may get done tonight.

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Stay tuned.......
 
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IT'S DONE! :beer bottles:

I went ahead and finished it up tonight.
All I needed to do was make a knob and a swing bolt. Not really much to it but I'll post a couple of pictures showing a couple of tricks.

I made the swing nut out of 2 inch aluminum, turned the shank down to 3/4. I wanted a radius where the thumbwheel meets the shaft. I left enough material to cut the radius out. I've never tried this before, I used a 3/8 ball end mill to cut the radius. Just set the tool on center, with one side of the ball cutting edge at the ''correct'' angle. Went in and took light cuts working back and forth so it didn't try to take the whole radius in one bite to minimize chatter. It worked great! :encourage:

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And the finished radius

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One trick I use to square the tool holder to the lathe when needed is to just run the holder up against the chuck, move the carriage as needed. and tighten the clamp nut when you get it square.

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The only parting tool I own :grin: It has never jammed. Note: DON'T RUN THE SPINDLE when using this type of ''parting tool''

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I already drilled & tapped the swing nut, but I wanted to chamfer the other side. So I flipped it over and used the tap drill to align the hole with the spindle so I could chamfer on center.

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And here it is, ready to use.

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and as I mentioned in my first post in this thread, I built this to hold a 20 inch chunk of 3 1/2 inch UHMW so I can drill a 1 inch hole through it. That project is going to be a little tricky so I'll post when I get to it in the next day or so.

Here it is!

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Thanks for looking and I hope someone can find something useful to take from this.:)
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