What's New at 120studio.com




2018 August 19

Sunday

New Article:  Quick Vise Weld With Nomacast.  Read the article to find out why, and how well it worked.


2018 August 14

Tuesday eve.

Metal & Shop


New Article:  How To Make a Right-Angle Bracket from C-channel, angle iron, or square tubing.  This is a really simple project that I meant to post a while ago, so here it is.  (I think I posted that photo, but not the article, a while back.)

This bracket type is about the most basic one you can make from metal;  it doesn't require any welding or joining together metal pieces. 

So, what's so good about it?  Find out.



2018 August 12

Sunday evening

For the reader who's working on that rotating vise... New Article:  Who Made This Rusty Rotating Vise?.  It might not answer the question of who exactly manufactured the vise, but you may enjoy the read.  Check it out.

I've also got an article on thread pitch gauges, but it's sort of under construction, so I'll post that one another day.



2018 August 10

Friday evening

Tools; Metal & Shop

The 1979 Taiwan vise upgrade project is still working well, except for the vise jaws.  Today the thin welds finally gave way from considerable hammering.  I was trying to knock a broken link out of an old piece of chain, and it wouldn't quite clear the diameter of the adjacent link.  This is when I realized that a good portion of those thin vise-jaw welds were probably what you'd call "white cast iron":  brittle, and not really suitable for hammering on.  The vise jaw weld pre-heat stage was insufficient, I think. 

To avoid the white cast iron type of composition, the preheat temperature should have been much hotter, the pre-heat more thorough on the workpiece, and the cool-down period kept as slow (or slower).  I knew the preheat was inadequate, even when I did the welds.



I removed one of the bolts or machine screws from the other jaw, and it looks like it's actually a standard thread.  5/16" NC, looks like.  So, instead of dealing with a pre-heat and all that, I think I'm just going to clean out the rusty threads, find suitable fasteners (somewhere?) and re-attach the jaw liner that way.  You can see here where the threads are flattened because of hammering.  (Too much would just break the ledge off the lower portion of the vise jaws, which happens sometimes.)



By the way, the anvil welds are holding up great, even after heavy use that included 3-lb hammering.  (I knew the jaw welds were kind of tenuous, because they were mostly with 1/16" electrodes that were too thin for the purpose anyway.)



2018 August 6

Monday

Tools; Metal & Shop



The reader who asked about the rotating vise had also sent a few other pictures of the project.  I'll try to post a couple more of these when I get the chance.  This photo shows the movable jaw and the slide, and you can see the pitting in the metal, much more visible after the rust has been removed.

The tolerances on a vise can be rather close, especially on a vise that has a round slide.  So you could end up having to soak one of them in kerosene, MMO or something like that, or perhaps use a shop press to unstick the slide.  Just watch that it doesn't suddenly give way and send a multi-pound chunk of iron moving at high velocity.

You can also see that conical piece that goes on the back end of the vise;  it holds the main screw, and you can guess that if you put too much clamping force on something, it could break that piece that attaches to the outer ring.  But a lot of these last for many years, so it must be at least a semi-decent design.



2018 August 4-5

Weekend

Electronics



So you've got this power supply, and you notice the device that it's powering keeps cycling between "charging" and "on battery power".  It happens a whole bunch of times.  So you check the connections, and everything's plugged in properly.

And that's when you notice it.  The power supply is HOT.  I mean, so hot that you drop it instantly.

After it's been unplugged for a good five or ten minutes, the outside of it is still at 168 degrees Fahrenheit. 



Top of that 400-volt cap is slightly domed out.  Bad caps!!  But the immediate cause of all that heat was overcurrent in the transformer windings.  The transformer was still hot another ten minutes later, when everything else had cooled.












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