Saturday, March 20, 2021

Quick tips on marking out

I bought some real marking out dye, red and blue.  Blue in a spray can that lost pressure and put out 20 times too much.  And some red in a bottle.  That seems to get all over me when I use it.

Years ago, I found out that blue Sharpie markers make pretty decent marking out dye.  I bought a box of 10 or so...  I still have a few left.  And 5 years hasn't been kind to them....

I got this all on my hand. I tried some turpentine, and smeared it all over my palm and two fingers.  I found some IPA, isopropal alcohol to you and me, and it cut most of it off.  Oh, hey! I found a cut I didn't know I had!  Noice.

The blue seems to build up when you go over it a few times.  The black seems to strip off what is down already.  I like blue better anyway. 

I have some cutting to do, so here is the kit.

Not shown are the leak-o-matic marker and a Professor Pete approved visor.  

I used the firm joint for a scribe, it's was sitting right there asking to help.


Don't fight with the part you are trying to hold.  Especially if you are trying to be accurate.  I didn't and I was.  That Stanley vise was a great score on 'bay.  I was shocked at how cheap I got it.  Paid about the same for the swing jaw and grooved jaw.  Got impatient, so paid a premium.

The profile wasn't tapered, but it didn't like the smooth jaws, so a scrap paper liner firmed up the grip.  I like to use what's handy, and the bit of cloth in the paper helps, it seems.

That green paper used to fill up my tank with gas.  Something changed though.  The gas didn't get better, or bigger.  The tank on my truck didn't get bigger, but the paper doesn't seem to fill it up anymore.  I measure the paper, and it didn't get smaller.  Plus, it still has the same number on it.  I guess it just doesn't pull as much weight as it used to.    Might as well use it for something constructive.  The folks that made it seem to want to take that away from it...

Those marks are within 1/64th of where I wanted them.  And that is good enough.  Now, I need to find a hatchet to cut it, a hammer to fit it and a maybe some self-tapping screws to hold it down....

Monday, March 15, 2021

Unknowable Inscrutible Mechanical / Electronic Marvels


A lot of wisdom there, John.

STxAR, I love reading these. I only understand about 20% of it, but it is fun trying to figure it out.


 Thanks, TB.  You made me think....

I find myself drawn to things.  Mechanical things.  Electronic things.  I can't really help it.  I cannot begin to compile the amount of stuff I worked on over the years.  Things I tore into as a kid.  Things that I reduced to scrap and was unable to reassemble.  Things I fixed for others, or myself.  It's called "The Knack".

Not me, but a reasonable cartoon representation

I was undiagnosed as a kid.  But everyone knew I had it.  Dad was not impressed.  I can't  really blame him though.  He had to fix what I couldn't or didn't.  (We won't talk about the stuff he couldn't fix and how he vented his frustrations.  He got some aerobic exercise, and I learned some things shouldn't be fooled with.)

There was an old hardware store in downtown Lubbock.  High on a wall was a sign that said "Knowledge can take it apart, Wisdom can put it back together again."  Dad pointed at it once, and said, "You are very knowledgeable."  That wasn't his only backhanded compliment.  But it prompted me to go farther, and get "wisdom".

I have this curiosity that compels me to investigate.  The best thing I can do is try and direct it.  I haven't been able to stop it.  And I don't want to.


99 Suburban update

Did you know that a 5.7 Vortec likes about 60 psi of fuel pressure to start reliably?  It'll run on 50, but starting is 60.  And that injector I replaced worked great.  Until the fuel pump began to really have problems.  Also, if you run one dry, it'll kill the pump.  One and done.  And this one appears to have had that happen some time in the past.  I killed a 98 GMC Savanna pump once just like that.  I learned to keep it full.  But this one went dry once too often some time in the past.  Even if it was only once.  New parts on the waaaay....

Friday, March 12, 2021

Guest Post, part 2


Next project 
Spray gun nozzles.
I'd bought one of these 15 dollar spray guns a while ago to try it out and spray some latex. 

But the instructions advised against spraying latex. The gun sat on a shelf for some time and I got interested again when we did a medium facelift in our bathroom and decided to paint the two pine doors when the weather turns nice enough to do it outside this year.
The internet says that you can drill out the nozzle on the cheap gun, thin the latex a bit, and get good results. The internet also says that instead of drilling out the nozzle from 1.4 mm to 2.0 mm I could buy replacement nozzles that would fit the gun. 
I ordered a 1.7 mm and a 2.0 mm nozzle from China. When they arrived they didn't fit because the thread number was the same, but the threads were a bit larger than the original. They are some sort of stainless steel.  

The internet told me how to change the gear train to cut metric, and I followed the chart numbers. But the threads were close to the shoulder of the nozzle, and my external threading bit  just wouldn't fit. I bought this set because I wanted an internal threading bar because the tool my dad had ground only allowed me to thread a short distance. 
The design of this tool let me cut very close to the shoulder, and the carbide insert worked great to cut the stainless. I used a HSS parting tool to deepen the thread relief groove next to the shoulder, then I turned down the OD before the threads and used the same tool to cut off the existing threads. Then I locked the half nuts, and threaded the nozzle by turning the chuck by hand. 
On the second nozzle I used power. I also changed my technique a bit. I found that my right hand wants to turn the lathe's power switch in the right hand direction and whether that's muscle memory or habit I don't know. I do know that that habit caused a minor crash against the shoulder of the second nozzle when I went forward instead of reversing as I had intended. I then changed to using my left hand to reverse, and that seemed to work out very well. 
It went this way:
Skim cut by hand rotation of the chuck. 
Reverse until the tool is clear.
Zero the dial.
Advance the feed a couple of thou.
Cut the threads and stop the feed. 
Power reverse. 
Repeat until the threads will fit where they have to go. 

I learned a lot about metric threading, and I found out as expected that using a HSS parting tool to cut stainless was a bit tough because it took a bit of extra pressure before the bit dug in and started cutting.

Something we don't ever seem to talk about. What did it cost?

The HVLP gun cost 15 dollars. 
The two replacement nozzles cost around 30 dollars but each nozzle was a complete set of the long part, the nozzle and the nozzle cover.
The carbide threading set cost 41 dollars. 
And maybe two hours total standing at the lathe.
I was talking to a friend who asked whether the additional investment in the 15 dollar tool was worth it. Hmm. After thinking about it, I returned to Harbor Freight and bought a 75dollar HVLP spray gun. It was an easy rationalization. :)
And much like the old saying that if you only have a hammer, then every problem looks like a nail, if you have machine tools, then every problem can be solved by using them. Except that every problem really can be solved by using machine tools. 

Disclaimer.  I am not a real machinist, and I rarely figure out what speed and feed I should be using. It is very satisfying to create something that does what you need it to do by using machine tools and your skills. 

Take care, 

STxAR addendum:  If you machine you are a machinist.  You may not be a pro, but you aren't a button pusher either.  Us "figure it out on our own" guys are just like the fellows that did the same thing in the past.   Eating trig tables and squirting out parts....

Thursday, March 11, 2021

Guest Post!!!

 John in Philly has commented quite a few times, and we've run into each other around the net-world on occasion.

He mentioned some work he had done, and then sent a blog worthy run down to me via email.  With pictures, yet!

I asked permission to repost and here it is, for your enjoyment:

                            The Lampshade project. 

Cast of characters.:
Me. John 

Wife. Best Wife Ever. 
Best Wife Ever bought a Baldwin Brass Company floor lamp a bunch of years ago, and the shade had once again aged out and needed to be replaced. The last time this happened we took it to a small backstreet lamp and shade repair store and they stripped the shade frame and recovered it. 
Time passed, and the shade aged out again and the cloth became brittle. 
But the employee that overhauls the shades had retired without a replacement. 
The owner of the store and Best Wife Ever worked together and agreed on a replacement shade of the same quality. We bring the shade home, and Best Wife Ever begins to install it. But the lampshade retention system used by Baldwin turns out to be a different size than the normal. 
The new shade won't fit and Best Wife Ever wants to use the new shade because she likes it. What to do? 
If only we had a small machine shop in the basement. Wait! We do have a small machine shop in the basement. 
All I have to do is to take some measurements, do a bit of math, and then machine an adapter so that Best Wife Ever can use the shade she likes. And since the lamp is now using LEDs or compact fluorescent bulbs, I can machine the adapter from PVC because heat isn't an issue. 
I mentally sketch what I need, dig through the leftover PVC fittings, find what I need to start, and begin  figuring out the tooling and sizes.I plan on making a screw together gizmo that will go over the three arms of the shade, and the brass finial that functions to hold the shade in place will screw into my gizmo. 
I will need to turn some ODs, cut two internal threads, and one external thread. 
OK. This will be my first ever internal thread and I've had that lathe for a little more than 20 years. 
The thread count is 20 tpi and I need an internal threading bar. I find that I don't have an internal threading bar, but I do find something I can use in my shoebox of hand-me-down tool bits I got from my machinist father.I can use this to make it work, and when I can use a tool that my father made with his own hands, I can literally feel the connection to him. 

This is the brass finial that won't fit on the new shade. 

This is not the shade, but shows how the center ring should fit up into the finial, and then the knurled ring will push the triple arms up the slots.


But the new shade has a center ring that is larger than the original and will not fit up into the brass finial.

There isn't enough metal to bore the hole larger. After some time at the lathe, and a trip to get a PCV piping adapter sized to make the knurled ring, I have completed the adapter. 

No wires were used to check the thread sizing. I used the technique of cutting the threads until the parts fit together.  I was getting ready to part off the PVC knurled ring, and I realized that plastic is way weaker than metal, so I left it long. 
Best Wife Ever is happy and I got more learning on single point thread cutting, and using the change gears. 

The most interesting part was when I was cutting the internal threads for the knurled ring and I needed to figure out what size to bore out the ID before I started cutting the threads. The threading charts lacked information on what I determined to be 1.33" X 20 tpi internal threads.  I spent some time reading up on the subject, then did the math for 20 tpi thread depth and it all worked out.

Adapter and shade before adding the finial to it.

Yes, there's a shoulder in there.


John in Philly.


Here is a quick tutorial on internal threading by Professor Pete


 All in all, a successful project, and a happy missus.  Win - win!!

Thanks for letting me post this, John.  Job well done!

Monday, March 8, 2021

Machinist Rage

 I don't know who you are......

                    But I will find you........

                                And when I do.......




For the love of all that is holy, or just because some poor dipstick is going to take it apart someday, put a flat on ANYTHING that is gonna get a set screw driven into it.


I mean, how hard is this.... really....