2015 POTD Thread Archive

roadie33 said:
How did you make it?
Can you post some pics and instructions?
I have a big bucket of Aluminum shavings I would like to smelt back to useable form again.
How hot does it need to be to smelt 12L14 ? Got 2 buckets of those.
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I posted in the wrong reply section so you will have to scroll down to find my real reply.
 
f350ca said:
Turns out its a Hamilton Tapping machine.

The table moves up and down with a neat ratchet on the handle to get it positioned. When you bring the work up to the tap the spindle slides up and the friction drive turns the tap in, stop applying pressure the tap stops. Pull down on the part and the tap reverses.
No idea what I'll use it for, most of my work is too big for it but it needed some lovin.
Tore it down, sand blasted all the castings and motor, and gave them a rattle can paint job. The shinny parts got buffed and one bearing replaced for a total of $3.99. Found the old motor in stock, hooked up a cord and it sprang to life running almost silently.

IMG_1631.jpg
Greg
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That's quite an interesting mechanism! I might just get a wild hair and try to build something like it. My only concern would be the rotational speed ... looks like it would be turning pretty quickly with that motor and pulley ratio. If I built one, I'd probably go with a variable speed DC motor.
Thanks for the post!!!
 
I was concerned about the speed too. It had a flat belt pulley on the drive, a brochure I found on the net showed the driving pulley the same size. I replaced it with the v-belt to get some reduction. After playing with it (haven't tried tapping yet) the sensitivity is such that I don't think the speed would be a problem, you control the speed by letting the drive slip.
The chuck that was on it appears to be a good quality one but I need to find a key to give it a try.
A few interesting and elegant design ideas were used. The knob at the top elevates the head to tighten the belt. The nut below the spring on the table is a depth stop for tapping or drilling, The spring is only there to hold the setting. There was a square table available that sat on the round one, it had a finger at the back to hold your work down while extracting the tap.
Greg
 
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Several years ago, when I was equipping my shop, I purchased a DRO for my mill (probably from Little Machine Shop). I never got around to installing anything but the x-axis device. A couple days ago, I decided to finish up the project and install the monitor and the y-axis. I had to make new mounts for the x-axis to allow for the cable that exited from the top to clear under the vise. After doing all that (beautifully and tediously, I might add), I finally got around to hooking it to the monitor only to discover that it doesn't work.

It went crazy. Resetting everything several times didn't solve anything, in fact after about 30 minutes of head scratching and tinkering, the display on the x-axis unit froze up on something like 72 and something inches and wouldn't even work when not connected to the display. I left the shop late last night muttering about how I had just screwed myself — at great effort.

Not only that, but the y-axis device that has done nothing but sit in its box, in a clean protected drawer for years also wouldn't even fire up. Fresh battery, turn it on, nothing. Push the buttons 50 times, clean the contacts, more futile button pushing, still nothing.

This morning, I went back up and fired up the x-axis without cabling to the monitor and it was working again. Inscrutable. But, the y-axis did me no such favor. It is still dead. At least I'm back to where I started.

I guess I have a new project, now. Funny how projects evolve.
 
roadie33 said:
How did you make it?
Can you post some pics and instructions?
I have a big bucket of Aluminum shavings I would like to smelt back to useable form again.
How hot does it need to be to smelt 12L14 ? Got 2 buckets of those.
Click to expand...
12L14 @2590°F
Aluminum metals like 6061 are @1205°F preheat prior to 860°F will reduce melting times if you have a lot to process.

For both metals it's suggested to melt solid chunks and add the chips to the melt to reduce slag production. you are going to want as rich of a flame as possible, alternatively an induction furnace that is oxygen depleted would be ideal for melting steel chips especially stainless. plain borax like "mule team" is a perfect flux to use in steel melt.
 
Franko said:
Several years ago, when I was equipping my shop, I purchased a DRO for my mill (probably from Little Machine Shop).
Click to expand...

I have an older LMS DRO on my mini-mill. It's their part number 2016 (long discontinued) and was called the "Economy Digital Readout." The display unit looks quite a lot like currently available Shars units. The scales are essentially iGaging scales (or maybe Accuremotes, as they're stainless steel) and the cables connect to the display with round mini-Din connectors.

I recall having frequent problems with mine, mainly due to batteries going bad in the scales. Finally did some mods ... got rid of the itty bitty batteries, soldered in some tantalum capacitors, cut off the funky connectors at the scale end of the cables, soldered the cables in, connected the power leads to an AA cell in the display and (IIRC) added some more capacitors at the display end of the power leads.

As far as troubleshooting your scales, it sounds like you've already tried disconnecting the cable from the scale. Did you try checking the battery for freshness/voltage? Obviously, you can check for cable problems by swapping in a known good one. If the problem can be isolated to the display, you'd have to get a new one (from Shars).

Beyond that, I don't know what to suggest. If the problem is in the scale, you might get in touch with Davidh and order one or more new ones from him. I've bought from him a couple times. His prices are better than Amazon or other vendors, and he's very helpful.

Best wishes!
 
What did you make your crucible out of?
Is that a Flywheel for the base?
 
roadie33 said:
What did you make your crucible out of?
Is that a Flywheel for the base?
Click to expand...
That is a 5 gal Propane bottle and yes a flywheel off of a 12 hp Techumseh riding lawn mower engine. The crucible is made out of a small propane bottle.
 
hman said:
... As far as troubleshooting your scales, it sounds like you've already tried disconnecting the cable from the scale. Did you try checking the battery for freshness/voltage? Obviously, you can check for cable problems by swapping in a known good one. If the problem can be isolated to the display, you'd have to get a new one (from Shars).
...
Best wishes!
Click to expand...

Thanks, hman.

I agree, the connectors suck, and leave the innards of the unit open to the elements when plugged in. Did I understand you correctly to say that you hardwired the whole thing?

I spoke to Chris at Little Machine Shop this afternoon. He said they quit selling Positron scales because of numerous customer problems. He vaguely remembered something about ground loops, suggesting I Google it. I did and came up mostly empty. From the discussions, I couldn't discern if the solution is to isolate or firmly ground to the mill.

Most probably, my spare batteries are old. I did one that would fire up the y-axis scale, so even if it can't get the rest of it running, I'll have that.

Chris made me a very generous offer for a replacement. Not free, but generous considering I purchased it about 8 years ago. I don't know if I can swing taking him up on it, as I just committed to purchase a new PM1127 last week. My shop budget is shot for a while.

In my search, a discussion inspired me to check the handwheel vernier against the digital scale. Results are confusing. Vernier reads .010 while digital reads .009. It does not progress linearly as .050 vernier is .047 digital. I have no ideas how to decide which is correct. Probably both are wrong.
 
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