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"Built Dam Strong!"

18 January 2015

TOS FA3V Mill Update: It's dead, Jim.

Last weekend was supposed to be a cold, but awesomely productive weekend filled with lots of cool stuff to update all my readers on. The fact is that I managed to get two planned things done (out of a list longer than the equatorial circumference of the Earth) and a whole lot of unplanned things done because the mill suddenly stopped working. That started a whole chain of events adventuring down a rabbit hole that I still haven't gotten back out of yet.

Fall down the rabbit hole with me . . .

That weird looking thing is a fuse. It is an old European standard of fuse that was invented after the US standard Edison fuse (the screw in type you still see in older homes today.) These fuses aren't very easy to get a hold of anymore. Why am I blathering on about fuses that you can't get anymore?
That wire in the outside of it is a ghetto fuse bypass. I was so shocked I refused to believe that it was a bypass at first, but Dave brought me around to face the facts that the mill was down for the count and we needed to do something about it before we set something on fire, which would do no one any good at all. Fine.

What do you do when nothing else is open and you need to get work done? You go to HDRS. (Home Depot Racing Supply.) We looked to see if they sold any three phase panels or breakers or anything. They do not, as that is considered commercial and industrial. Fair enough. Dave and I put our heads together and confirmed that the fuse holder did indeed have the standard Edison Fuse thread, so we postulated that if we could somehow safely extend the Edison fuses that are readily available, we could get the mill back up and running without any problems.

Dave suggested using aluminum rod. That was a flipping brilliant idea. I bought two fuses and a 1/4" diameter aluminum rod and we got to cobbling together this:
The white porcelain cap is the holder for the fuse. The system itself is pretty brilliant. The width of the small end prevents fuses of larger capacity fuses from being inserted (much like the Edison rejection type fuses which have different threads for different fuse ratings, preventing anyone from inserting a larger fuse into the circuit and thus preventing a fire, especially with old knob and tube wiring), while having a very good contact surface area. The fuses themselves have a colored bit on the large side that is seen through a sightglass on the end of the fuse holder. When they blow, the colored part pops, showing very quickly that the fuse is blown. It's a really well thought out system . . . but circuit breakers are something that will be added in to the mix in the future.


Here's the fuse panel:

Shazzam! The mill started working, but we lost the power feed. Inspecting all the fuses revealed half of them to be bypassed because they had blown previously. We headed back to HDRS, bought enough fuses to convert the whole mill and busily set about replacing them all.
Here's the whole panel converted:


Even after replacing the fuses, the mill was still not power feeding to the opposite direction. Since we weren't sure what was going on, Dave convinced me to pull off the covers over the selection rotary switches. We traced out the wiring path (we think) and thought we had fixed it, but the poking around we did started breaking wires. Fifty year old wiring doesn't like to move. It didn't help that they tinned the ends of the wired, leading to most of the wires breaking just beyond the solder joint, which is why that method is no longer practiced by anyone who cares about longevity and electrical system robustness.

We also suspect one of these relays:
After 50 years, they might be faulty. it seems it is getting the switching signal, but won't change position.

One of the relays (for the spindle) had been replaced already:


Four big relays total:
It is not surprising that the relay might need to be replaced. This bears further investigation.

All the guts pulled out and open for surgery:


Dave found this wrench highly appealing:
I don't want to know what he did with it when my back was turned.

One of the few things that went well that weekend was welding in this (poorly fitting) patch panel on Dave's pedal box thingy:
Of course I didn't get an after picture, but I managed to get it smacked into place well enough to weld and filled in all the gaps.

Another really frustrating thing was that I goofed and ordered a 1/2" straight shank to Jacob's 33 taper arbor so I could use the chuck that I bought. I totally forgot that I hadn't ordered a 1/2" collet. I couldn't use the chuck, so even when we got the spindle running, I couldn't have actually DRILLED ANY HOLES AT ALL! Ugh. By the time I realized this, it was Friday during the day. What to do? turn to Amazon Prime + overnight shipping for an additional $4 for a 5/8" to Jacobs 33 taper arbor. Problem solved. Until it gets to be late in the day and I call up Amazon and wanted to know where the darn product was I ordered. They determined it was on a FedEx truck somewhere in Virginia and was scheduled to be delivered on Tuesday. Tuesday is NOT overnight. This is one of the few times I have ever been disappointed with Amazon's service. I was refunded the extra I paid for shipping. 

It arrived as scheduled on Tuesday:

I set about measuring TIR (Total Indicated Runout):
The good news is that the collet chuck and arbor barely wiggle my tenths (machinist speak for then thousandths of an inch) indicator. The bad news is that that chuck itself gives a TIR of about .0045", which is good for drilling wood or general non-precision, but pretty poor for precision drilling work. I will see if I can get the chuck seated better on the arbor and test the TIR again, but I may end up having to get a more precise chuck in order to finish the bell housing as precisely as it needs to be, as reaming holes should be pretty darn spot on and not wobbling about where thousandths of an inch matter.

And that is pretty much that. I'll have another update soon on getting the mill running again, but that is definitely a story for another time.