Let me introduce myself: I’m a long time geek working in the computer industry on open source software. I spend too much time in front of a computer. Way too much time.
I needed to do something to get away from the computer. Something physical – something to get dirt under my fingernails and sore muscles. Something where you can actually touch and see results at the end of the day.
So I decided to restore a car. [Insert scary music here]
Note: while WordPress puts the most recent posts at the top, you can also read the story in order starting with The Car Shows Up.
With the lathe cutting properly and demonstrating that I can cut M24-1.5 threads I could move on to making a retainer to bolt the frame to the jack. Dropping into engineering design mode I defined several requirements for this part:
Secure the frame to the jack without wobbling and able to take off-center loads.
Attach using the M24-1.5 threads in the jack.
Able to screw the retainer into the jack.
At one level these requirements are pretty straightforward. But there are many ways to implement them.
The first requirement involves torsional loads. The best way to do this is by providing support as far away from the bolting point as possible. The easiest way to do the is drill a hole through the top and bottom of the frame and bolt it in place. But this would leave a bolt head sticking up on top of the frame where it could hit whatever I was lifting.
Another approach is to just bolt through the bottom of the frame and make the bold as wide as possible. After allowing for the thickness of the tubing and the corners of the tubing the widest this could be is 1-3/8″. And I have some 1-3/8″ steel rod.
But wait – there is a raised lip around the threaded hole in the jack. This provides more material for the threads but means I can’t have a flat bottom on the retainer. The retainer has to have a 0.080″ recess a little over 1-1/8″ in diameter. This could complicate making the retainer.
The threaded hole in the jack is close to moving parts, so the retainer can’t stick out below the bottom of the mounting plate. The threaded hole in the jack is about 0.25″ thick, so the threads on the retainer can’t stick out more than about 0.30″.
When cutting threads on a lathe you need a runout area for the cutter that extends at least 1/4″ past the threads. Cutting threads up to a shoulder is difficult – especially at my skill level!
The easiest way to screw in the retainer would be to have a hexagonal head on it like a bolt head. They make hexagonal fixtures to use on a milling machine for applications like this. But it would be easier if I could just use a bolt head.
After sketching up several ideas I finally decided that, although elegant, it would be too hard to make this as a single piece.
I moved on to looking at ways to make two or three piece designs and weld them together. I came up with several approaches that looked like they would work. But the all involved a lot of work. And welding a thin threaded part to the body was giving me lots of heartburn.
Then inspiration hit – use an actual bolt! Specifically, use a standard 1/2″ bolt. Drill a 1/2″ hole through the body of the retainer. Cut a recess in the face of the retainer to clear the lip on the jack. Cut the body of the retainer to length so that the head of the bolt would be just below the top of the crossmember of the frame.
The threaded piece became simple: Make an adapter with M24-1.5 threads on the outside of a rod. Drill and tap the inside of the rod to 1/2″-13. Cut off a 0.30″ length that is threaded on both the inside and the outside.
Run the bolt through the body of the retainer. Thread the adapter onto the bolt until it sticks out the bottom of the retainer the needed amount. Cut off the part of the bolt that extends past the adapter. Weld the adapter to the end of the bolt. Viola! – you have a ready to use retainer!
Retainer for jack frame
Take the retainer over to the jack, drop it into the frame, and screw it into place. Strangely, it actually fits. Snug it down with a ratchet and socket and check to see how sturdy it is.
Sturdy enough! I wouldn’t try lifting the entire car balanced on one side of the frame, but for loads like a gas tank it should work great.
The gas tank is leaking when filled up. Not Good! I had this problem a couple of years ago and fixed it. Looks like the problem has returned… No choice but to drop the tank and fix it again!
It is fairly straightforward to drop the tank using a floor jack to support it. Except that the top of the jack is only about six inches wide and the tank wobbles on it. And wants to fall off. Especially when there is some gas sloshing around in the tank. This job would be easier if the jack were wide enough to support it.
Well, what would it take to make the jack wider? Pulling up the rubber pad on the jack reveals a bolt securing the standard 6″ square plate to the lifting arms. It should be possible to replace it with something wider.
Searching around the shop turned up a frame from a previous project that didn’t work for that project and was tossed into the “materials for future projects” pile. Well, this is a future project!
Cut off the unneeded bits and weld in a center section of 2″ x 2″ square tubing (also from the “materials for future projects” pile). Drill a hole in the middle of the center section for a bolt. Now we just need a proper size bolt.
Which is where the project came to a screeching halt. Detailed measurements showed that the jack uses M24x1.5 threads. This is basically a one inch diameter metric size – which I don’t have and isn’t readily available.
No problem! I have a lathe and can create a custom part with the needed threads.
This is where things went sideways…
I had upgraded the lathe with a Quick Change Tool Post – QCTP. A QCTP is one of the most valuable upgrades you can make to a lathe. It allows you to change the cutting tool you are using in seconds instead of minutes and without setting up the cutting tool each time you use it – a major productivity gain!
The first task was to make a test piece to make sure that the threads would work. To do this I needed to first turn down a piece of steel rod to the needed size and then cut the metric threads.
When I ordered the QCTP I had to choose the size – AXA or BXA. The BXA size is the largest that would fit my lathe. Bigger is more rigid and more rigid enables deeper cuts, more accuracy, and better surface finish, so BXA it is!
I’ve been having problems setting up the cutting tools – they ride just a little bit too high. Turns out that the tool holders for the QCTP are hitting the cross slide on the lathe. Yup, I should have gone with AXA.
Well, the lathe isn’t the only machine tool in the shop! Do a bit more shop tetris and expose the milling machine. Mount the 2″ facing mill on it. Flip the QCTP tool holder over so that the bottom is up. Adjust the mill to take a 1/8″ cut off the bottom of the tool holder and fire it up.
This is a small milling machine and the tool holders are hefty blocks of steel. I wasn’t sure if the mill had enough power to take a full 1/8″ cut in a single pass. And I was curious to see what kind of surface finish it would leave.
To my pleased surprise the milling machine chewed through the tool holder with enthusiasm and no signs of strain. While throwing hot razor sharp chips everywhere.
The first tool holder came off the milling machine with great surface finish. Take it over to the lathe and it slides smoothly onto the QCTP and locks solidly in place. This is encouraging!
Take it off the lathe and install one of the cutting tools. Put it back on the lathe and try taking a facing cut across a steel rod. This is a bit of an acid test – if the cutting tool is adjusted properly it will leave a smooth face across the end of the rod. If it isn’t adjusted perfectly it will leave a little nub sticking out of the center of the rod.
After several test cuts to get it dialed in I got a perfect cut across the end of the rod. And there was moderate rejoicing!
Repeat the process for the other four tool holders, including loading and setting various cutting tools. Finally, the lathe was working properly!
Time to make a test piece to see if it would screw into the jack. With everything set up properly turn a chunk of 1-1/4″ steel rod down to 24mm.
It has been many hears since I actually cut threads on a lathe. I had already checked and knew that the lathe could cut 1.5mm threads. With some configuration changes…
Dig out the manual for the lathe and see what is required to actually cut 1.5mm threads. Hmm, the back gears need to be changed. Go digging through all of the accessories that came with the lathe. OK, found a pile of gears. Looks like I need a 76 tooth gear and a 42 tooth gear. After cleaning the gears and studying them closely I found one stamped with 76 and another stamped with 42. Holding them up to the existing back gears installed on the lathe I could see that they wouldn’t fit. Why am I not surprised?…
Go back to the manual and study it closely. Hmm, it looks like one of the pivot arms has two adjustments. Cleaning it up reveals a socket head cap screw and a bolt. Well, maybe this almost makes sense…
Loosen the bolts and then work the old gears off of their shafts. Slide on the new gears and then use the various adjustments to fit them to the main drive gear. Strange, everything is fitting together! Add some grease to the gears, power up the lathe, and engage it. Everything works! This is really making me nervous.
Set the gearbox to B6 (which the manual says will cut a 1.5mm pitch thread), shift the lathe to thread cutting mode, and start making test cuts. Alignment is critical – you have to engage the feed rod at exactly the same place every time to cut a clean thread. Or you can run it forward to cut the thread, stop at the end of the threaded area, back out the cutter a bit, run the lathe backward, run the cutter back in to the starting point plus the depth for the next cut, and repeat until you have cut full depth threads.
All this took a bit of practice. I screwed a number of things up. I also managed to break a couple of threading inserts. But I ultimately succeeded in cutting threads that looked good.
But were they the right size? Dig out a 1.5mm thread gauge and measure the newly cut threads. A perfect fit! While really encouraging, this wasn’t definitive. Take the test piece over to the floor jack and try to screw it in. It fit perfectly! And there was much rejoicing!
Checking to see if test piece fits into jack
At this point I had everything needed to make the actual part.
At the end of the last post we had a pretty well destroyed dash vent with a broken off cobalt drill bit buried hopelessly deep into it. With nothing to lose we might as well destroy it further and see if we can salvage this debacle.
Start with a round of Shop Tetris to gain access to the mill. Remove the cover from the mill and dig out the tooling needed for this job. Clamp the vent body in the machinist vise and start carefully drilling a series of holes around the broken drill bit. This time using less brittle HSS drill bits.
Careful and paranoid drilling left a series of almost connected holes around the broken drill bit.
Next load a 1/16″ end mill and start carefully milling out the metal between the holes I just drilled. Take it slow, make shallow cuts, and gradually work around the broken drill bit. Fortunately the vent body is made out of a soft metal, something like zinc or Zamak which machines easily. But I still managed to break several of these tiny end mills.
The jagged end of the drill bit was finally exposed enough to grab it with a pair of needle nose pliers and pull it out. Finally! Leaving behind a large jagged hole…
Mix up a batch of JB Weld (steel filled epoxy often used in the workshop). Fill the hole. And walk away for the 24 hours JB Weld needs to fully cure.
Coming back the next day, carefully mark the now solid JB Weld and drill a hole for the roll pin. Test fit it. Hey, it looks like this might actually work! Now back to the original job that was hijacked by this tragedy.
DashVent fixed with JB Weld and drilled for roll pin
The initial plan was to use TPU washers on each side. I had printed up several in various thicknesses. Although flexible, TPU is still rather hard and doesn’t squish well. After trying various alternatives the best approach was to use a TPU washer on one side and the original wave washer on the other side. This was the only thing I could find that would both provide enough friction to hold the vent in the up position and allow me to re-assemble the vent.
It finally came together. I had the vent body re-installed in the vent assembly. Testing showed that it now stayed up. One down, one to go!
The second vent body came out the same way. Once again the only way to remove the roll pin was to drill it out. This time I did things differently! The first difference was to use the milling machine instead of the drill press. The second was to use a High Speed Steel (HSS) drill bit instead of cobalt. HSS is more flexible than cobalt and doesn’t break as easily.
With great paranoia and care I managed to drill out the roll pin. Re-assembly was the same as the first vent. And the second vent also worked!
Re-install the vent assembly in the dash and check off this project as done. Now, where did I leave that heavy drinking???
Step one is to remove at least one of the roll pins. Which are installed flush with the opening in the vent assembly. No way to grab onto the roll pins. Since roll pins are hollow, maybe thread something into the end of the pin and use that to pull the pin out? Nope. These pins are 1/16″ in diameter and I didn’t have anything small enough to thread into the tiny hole in the center of the pin.
If the pin wasn’t installed deeply enough into the vent body to bottom out in the hole it might be possible to drive it in far enough to clear the vent assembly wall. A few minutes of careful tapping with a pin punch and wiggling the vent body and it popped out.
The bad news is that this left so little of the pin sticking out that I couldn’t remove it from the vent body. After an hour or so of trying different things it became clear that the only way to do this was to drill the pin out.
This could be done on either the milling machine or the drill press. I have direct access to the drill press. Getting to the milling machine would require a round of Shop Tetris to gain access to the mill, removing the mill cover, and installing the needed tooling in the mill. Drill press it is!
Chuck a 1/16″ cobalt drill bit into the drill press. Clamp the vent body into the drill press vise. Carefully center the drill bit over the roll pin. Tighten the vise down so it can’t move. Start drilling.
The drill easily removed the roll pin. I noticed that the runout in the drill press is more noticeable than usual. Not a problem with the 1/4″ to 1/2″+ drill bits, but I need to be careful with this 1/16″ bit. The hole is almost deep enough… Carefully apply pressure to get the last bit of depth in the hole.
A quiet almost innocent sounding Ping.
Yup. Managed to break the drill bit. Pull the vent body out of the vise and examine the damage. Worst possible outcome: not only did the drill bit break, it broke off below the surface. No way to grab it and pull it out.
Recall that initial observation about broken bolts. This was much worse. Normally you can find a way to remove a bolt. Common approaches include welding a nut to the broken bolt, using a bolt extractor, or carefully drilling it out.
None of these will work here. Can’t weld a nut to it – the drill bit is only 1/16″ in diameter and broken well below the surface. No way to machine it out either – this cobalt drill bit is the hardest thing in the shop. The only things that could touch it are carbide or diamond, and I don’t have either.
This is where you scrap the part and get a replacement part or start over.
After examining many possible ways to deal with the problem it became clear that the best approach involved heavy drinking. The second best approach was to machine out the vent body around the broken drill bit until enough was exposed to grab and pull out.
This would cause a lot of damage to the vent body. But at this point there was nothing to lose.
Any 10 minute job is one broken bolt away from two days of hell. I’m not sure who originally made that observation, but there is a lot of truth to it.
The Imperial has an interesting AC design. There are two flip up vents in the middle of the top of the dashboard. When down they blow air on the windshield for defrosting. When pulled up they blow cold air on the driver and passenger. These vents, plus the floor vent, are responsible for distributing air from the AC.
Dash vents raised
Unfortunately the mechanism that holds the dash vents in the up position is worn. The driver vent will only stay up for a few minutes while driving. Then it falls down with a loud “clang”. The passenger vent doesn’t stay up at all.
With the AC somewhat working it becomes important for these vents to stay up. This is another one of the projects I’ve been putting off for years. Guess it is time to finally attack it…
Remove the mounting screws from the vent assembly, pull it out of the dash, and drag it over to the workbench for study.
The vent body fits closely into a cutout in the vent assembly. There are two roll pins that retain the vent and function as an axle for the vent to allow it to rotate up and down. Close examination shows that there are wave washers on each of the roll pins. These spring load the vent body and provide resistance to hold the vent body up – when new.
Wave Washer
At some point over the last 60 years these weakened. Perhaps wear in the washer or the vent body. Perhaps the spring became less springy over time. In any case something needed to be done to increase the friction between the vent body and the vent assembly.
Something… Something like flexible washers 3D printed out of flexible TPU in exactly the needed thickness. Well, these are easy enough to design!
With a plan of attack it’s time to get going on this project!
Another useful tool is a pick. I have a couple of them and use them fairly frequently. At times it would be helpful to have different sizes and shapes. Yup, time to hop on the Tekton web site and place another order.
This bin design went through a few iterations. While most of the picks had small heads, a couple had large heads that wouldn’t fit in a standard cutout. I really wanted to print this bin out as one piece, but there wasn’t enough space.
After trying several alternatives I ended up making the cutouts for the head of the picks over-sized on the first and last pick. I also put one of the picks horizontally across the top of the bin. With these changes I was able to fit all of the picks into a single bin that could be printed as one piece. The picks are packed together tightly, but you can still get them out.
While my random set of screwdrivers has served me well, it made sense to order a set of good screwdrivers. After exploring various options I ordered a 12 piece set of Tekton screwdrivers.
When they showed up ldiscovered they were bigger than expected. After playing with different layout options it was clear that this set would require an entire drawer. Further, the longer screwdrivers were too big to go in the drawer side to side, so the set had to go in front to back. Fortunately I now have enough tool chest space that I can dedicate a full drawer to this screwdriver set. Off to the CAD system!
The drawer is larger than my 3D printer, so this bin will have to be printed in four parts. Up until now this would mean creating four separate bins in the GridFinity Generator and then doing custom cutouts in each bin.
I’ve been taking an online course on Fusion and learned a new trick. I could create a single large bin the size of the full drawer, create all of the cutouts, and then use a cutting plane to cut it into pieces to print.
So I did exactly that – create a large bin and make all of the cutouts for the screwdrivers in this single bin. I also picked up another trick – creating a midplane between two parallel faces. Using the midplane command reduced this whole pricess to four clicks: select the midplane command, select a face on one end of the bin, select a face on the other end of the bin, and hit done. Bingo, a new plane exactly in the middle of the bin!
Select the Fusion split body command, select the bin, select the midplane we just created, and hit done. Result: two halves of the bin, ready to print.
Well, not quite ready – we need this particular bin cut into quarters. Repeat the process creating a midplane on the other two side of the bin, select the midplane and the body, and use the split body command again. Remember to select both halves of the body or you will just split one half of it…
Now we have four pieces that will fit on the printer. Print them out, drop them in the drawer, and add screwdrivers.
Drawer with screwdriver organizer bin
After using the organized screwdrivers I’m happy with the work. Knowing where each screwdriver is – and where it put it back – is easier than the old drawer piled full of screwdrivers. It does takes up more drawer space than the old pile approach. And is worth it!
After finishing the bin for the new Wiha screwdriver set I sorted through my old screwdrivers. Turns out that a lot of them are good. Some are junk, so separate those out, but a bunch are worth saving.
This random assortment of screwdrivers doesn’t seem to merit custom bins. And this collection is likely to change over time. Fortunately there is an alternative – the Fusion Gridfinity Generator will create hollow bins. And create partitions inside bins. This allows you to get around the standard bin sizes – for example, create a bin that is 5×6 Gridfinity bin units in size with 8 partitions across the 5 dimension. This will create a large bin with smaller “bins” inside it. In this case these bins will be just under an inch wide rather than the standard GridFinity 42mm (1.654″) spacing.
Play with the screwdrivers for a while and determine what width of bin will provide the combination of good fit and good packing efficiency. Use the GridFinity Generator to create a set of bins with the desired width and height and will completely fill the drawer. Print out a set of baseplates for the drawer. Drop in the baseplates and then insert the bins. Fill the bins with screwdrivers. Viola! Good to go!
I’ve mentioned targeted tool upgrades. Some projects, notably the electrical projects, have required small screwdrivers. I have one or two that fit, and have to dig through the screwdriver drawer to find them. Time to end that foolishness!
The small Wiha screwdrivers are good, so order a set. And, of course, design a bin for them.
After designing custom bins for ratchets and extensions there was space left over. No problem – I have more tools to go there!
First was a distributor wrench. This is a two piece tool with a roughly “L” shape which was a bit tricky to fit. Using the standard GridFinity bin sizes required a larger bin than I really wanted, but no choice in the matter – you have to work in integer multiples of the grid size. OK, push the distributor wrenches to the outside edges of the bin and use the center for something. What about the oxygen sensor socket that didn’t really go anywhere? Nice – fits almost like it was supposed to go there. A few iterations and this bin was done.
Some of the tools didn’t justify the work of creating custom bins. For these simply create a hollow bin in the GridFinity generator and print them out. With GridFinity you always have options!
Now for the socket drawer itself. I already had all of the sockets mounted on rails. While many people use GridFinity bins for sockets I like the rails – so, keep the rails and use Gridfinity for everything else.
The process I’ve been describing so far focused on designing the individual bins. While I haven’t mentioned it yet, I’ve been working with a set of GridFinity baseplates sized for the drawer space. In addition to holding the tools, the set of bins were designed to fit the available space. This required a fair amount of arranging and re-arranging the bins, plus some of the bins were designed to fit the available space around other bins.
GridFinity organizers for ratchets and extensionsFull socket drawer – now completely organized!
Introducing the Imperial Deathstar, a black 1963 Chrysler Imperial. This is one of the largest production sedans ever built, and arguably the best luxury car of its day.
Join me what will probably be a never-ending saga of grease, aching muscles, and an empty wallet as I work to restore this over 50 year old survivor to a reliable cruiser.
