2016 POTD Thread Archive

[dave_r_1]

Ugh. Returned the defective Sanborn 80 gal air compressor and brought home a more expensive 60 gal Ingersoll Rand one.

First, they have a warning label like this:

which to me indicates you aren't supposed to strap the compressor via any part of the top of it. Where the F**** are you supposed to strap it for transport? The thing is TOTALLY top heavy, and they are too cheap to even put some holes in the mounting plate to hook into.

Then, they talk about using a hoist to get the unit off the pallet. Again, you can't lift it from the top at all and their stupid 'sample lift' picture shows a nice wide horizontal tank that you can put straps around and even if it tips a bit, the straps easily prevent it from rotating it very far. You lift this vertical tank like that, it's tipping over.

And then they are too cheap to include compressor oil. Buy a "Ingersoll Rand starter pack". $160 for 2L of oil and 2 filters. The manual has a nice long compatibility list with a bunch of stuff under "Suitable" and a bunch of stuff under "Not Recommended". Princess Auto helpfully sells Rolair Synthetic Oil, which doesn't say what it contains and with a MSDS sheet that lists only one ingredient (between 30 and 60 %, quality!) that is not on either the "Suitable" or "Not Recommended" lists. Excellent.

And Ingersoll Rand is also cheaping out on their tanks, instead of having a fitting on the side of the tank like their old tank or the Sanborn, they share the outlet with the pressure-sensor switch, so the outlet port at a crappy angle and much more easily broken/damaged.

 

[kvt]

OK, How do you really feel about the new compressor.

"Ingersoll Rand starter pack". $160 for 2L of oil and 2 filters

Just another way to raise the price without rasing the price. Leave things out and make you buy them separately.
See, YOu purchase the compressor, and now you have to purchase the rest that use to come with the compressor. THe price did not go up that much, just a little, but now the extra 160 comes into play for what they left out.

No, they expect you to bolt that silly little pallet to the bed of your truck or something like that.

 

[Charles Spencer]

The drawer for my Kennedy tool box came in today:




As you can see, I'm mostly using it for lathe tooling.



My Craftsman hack saw was taking up too much room due to the motor being mounted in the back. So I turned it into an under drive:




I used my vise to flatten a cookie sheet a bit so it fits snugly underneath the saw. That's to catch the swarf and small parts that are cut off. It slides out further than that also.

 

[JimDawson]

Had a little project to do today. A customer asked me to machine a hole and an O-ring groove in these 316 SS caps.

If I only had to do one I would have just put it in the vice, but with three it was worth the time to make a quick fixture out of MDF since I had an old spoil board handy. This spoil board may have a little life left, still has some unused space on it, I'll save it for the next project. Only took about 15 minutes to mount and pocket the fixture. I would have spent that much time dialing each one of them in. I could have also done this in the lathe, but I would have had to grind a special tool to make the O-ring groove, over all it was faster to do it in the mill. These are about 3.5 inch diameter, and 0.250 thick. I made the pocket on size for the outside diameter to get a press (dead blow hammer) fit and 0.240 deep so the part would sit a bit above the surface for clamping. I pre-staged the T-nuts where the clamp bolts needed to be and centered the part over the T-slot.



This time I remembered to put in the screw driver slot to get the part out


First operation is to pilot drill and drill a 7/8 hole in the center. This required going in to back gear and about 120 RPM. This is some tough stuff. Using light sulphonated cutting oil.



Next operation is to pocket the O-ring groove. I also proved that a 1/8, 2 flute end mill will cut 316 SS when running backwards. For about an inch anyway before it broke. I forgot to reverse the motor rotation after I was in back gear OOPS!

1200 RPM, 2.75 IPM, 0.015 DOC. Cobalt endmill


Next is final finish on the hole. 1200 RPM, 2.75 IPM, 0.060 DOC, 3/8 solid carbide end mill.



And a final deburr with a 0 flute countersink, at about 50 RPM



Total time, including setup, was about 20 minutes each.
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[rwm]

Jim- Very pretty parts. So for a job like this, how do you approach it? Do you measure up the original and enter it into a CNC program first? Are all the operations CNC or are some (like the hole drilling) done manually?
Robert

 

[intjonmiller]

If I'm not completely mistaken, for basic operations like this (circles, drilled holes, etc.) it can usually be done directly in the CAM software.

 

[JimDawson]

Jim- Very pretty parts. So for a job like this, how do you approach it? Do you measure up the original and enter it into a CNC program first? Are all the operations CNC or are some (like the hole drilling) done manually?
Robert

Thank you Robert.

The customer provided a PDF of the hole and O-ring groove dimensions. In this case I measured the part for the OD and thickness and created a DXF file that I then imported into my CAM program. A very simple drawing, just concentric circles. Then I created three G-code files; one for the pocket in the fixture, one for the O-ring groove, and one for the hole finish. The O-ring groove and hole were done in two separate G-code files because of the tool change required.

I first centered the 0,0 point over the T-slot, then ran the fixture pocket G-code. This puts the part on center, and no indicating required.

You are correct, I did the drilling manually. I just told the mill to move to 0,0 in two axis mode and drilled the hole. For many projects with only one or a few parts I drill manually, it's faster than creating G-code for each hole drilling operation where you have several drilling operations. Each drill operation would require a different tool height for center drill, pilot drill, drill onsize, maybe ream, and/or tap. If I were doing a production run or doing a lot of holes in a part, then I would create G-code for each of the drilling operations with the tool height offsets.
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[JimDawson]

If I'm not completely mistaken, for basic operations like this (circles, drilled holes, etc.) it can usually be done directly in the CAM software.

You are correct Jon. My CAM software (CamBam) does have drafting capability, but it's a bit clunky to use. In this case I used AutoCAD to create the drawing, total drawing time was about 3 minutes. Time to create the G-code files from the AutoCAD DXF was about 5 minutes. And I did all of this at the machine computer, didn't have to go to my desk.
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[chevydyl]

Intjonmiller, were you meaning in the control like Mach? I'm asking this cause cam is exactly that, picking geometry and making the g-code to tell the control to move to those coordinates, however, yes, in Mach or most other controls you can use wizards or conversational to do drilling cycles and what not without having to use cam and a 2d drawing, or a solid model to pick geometry

 

[CarlosA]

Setup a spare lathe bed and carriage I had to hold all the lathe attachments. Also turned out to be a nice flat place to set a dividing head and tail stock.

To do: Clamp a plate down with small t-slots for the dividing head and tailstock. And make some sort of dovetailed "tree" on the carriage to hang all of the quick change tool holders on.