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What I did the first time I made a gear was machine some plastic (I think it was actually nylon.) It was less stressful than cutting metal, faster cutting, and low wear on the cutter (which was home-made, but that's another story.) That practice session was followed by by making a replacement gear for a paper shredder, which was a less critical thing to do than making a gear for an engine project.

I had two screw-ups: One was having the blank unkeyed and having it slip on the mandrel holding it. The other was the inevitable miss-count of the crank turning and the resulting last tooth being a skinny tooth. Smooth sailing after that and third time was the charm.

Gear making is very satisfying when everything goes correctly. I believe it is akin to releasing a freshly casted part from the sand, or fitting a pin so precisely into a hole that it snicks when removing it 😁

It can also be frustrating when things go wrong. This was one of those moments.

I indicated the gear blank mandrel and turned the first blank precisely 0.100" oversize due to misreading the calipers. Every tooth, all 60 of them, was perfect and didn't catch it until I checked the mesh on the engine. Bummer... I had already broken down the rotary table and re-trammed the vice. 🤡
crank gear blank.jpgtoo big.jpg

So redo the setup, and wait a minute..... should have prepared a blank first and I just removed the vice. Remember when you didn't have a vertical mill and drilled holes in brass plate on the drill press? Yeah... it grabs as it breaks through. Ripped the morse taper out of the drill head and marked the bit shank :mad:

Okay, back on track... lets make a gear again. Notice how the Ivan Law cutter works. It is eccentric so there is adequate clearance on the tooth even when sharpened many many times. It is also much more solid than a single tooth bit because of the disc shape. Pretty difficult to make each disc, but nice now that they are all done. the discs are 0-1 tool steel and the tooth shape is made with button cutters. Different sizes for each disc. Different discs for the N number of tooth gears just like the commercially available ones.
eccentric cutter.jpg

Miraculously this gear also came out with perfect evenly spaced and shaped teeth. But it had too much backlash (too small) and I wasn't afraid of rejection at this point. Also left the setup on the mill this time.

I used an image zoomed in closely to estimate how much and calculated/guesstimated it needed to be 0.005" more radius to mesh correctly. I also watched a video about backlash and how much tolerance there is on full size gears. So let's make another larger gear blank.

too small.jpgjust right.jpg

Perfect fit with no noticeable backlash and easy to spin. So I carefully broached it and made a wee little key to index it to the crankshaft. Happy dance time

crank gear broach.jpg
Oh Yeah Dancing GIF
Piston Rings

I have followed the method listed at Jerry Howell's site a few times
link below

Making piston Rings for gas Engines

Needed to make a 1.002" sleeve and mandrel. Apparently I never knew, or forgot, that the dimple in the boring bar can be used to set the center height. Made 8 rings and they all parted nicely but with varying thicknesses. Split them and used a previously made setting arbor/mold to heat treat. Slathered with boric acid and wrapped them in foil this time.
trimble tool.jpgring boring t ool.jpg

foil and boric scale.jpgheat oven.jpg

This time I was able to use a heat treat oven I made this year with my new TIG welder. It's only 120V so it takes a while to get to temperature, but it gets there. I shut the oven off and left them all night. Several days later I attempted to unwrap them and what a mess. The aluminum foil had fused to the boric acid paste and the rings did not take the set.

Puzzled as to why, I reread the directions and noted that the temperature given in Celsius differed from the Fahrenheit temperature. Last time I did this I used my propane forge and didn't really have much control of temperature so I reasoned that maybe the 965F that I set on the oven may have been too low? Or that I need to remove from the oven and let air cool faster.

mess.jpgno spring or gap.jpg
I did both and avoided the tin foil also. Heated up to 1100 F and removed from oven after 30 minutes. Used a worm gear hose clamp to hold the flux over the rings and that worked better. The rings were scale free and the flux rinsed right off. They also took the set and was able to file the ends gapping them to 0.005" when compressed in the sleeve.

proper ring set.jpgreducing OD.jpgfitted to piston.jpg

I think I'm over the hard parts now, so I set the valve timing
thanks sprocket, I had read about the boric acid online but not sure its the best fit for small parts like this. I will try your suggestion next time.

Oiling hatches, knobs, grab bars

Decided to do some easy parts using brass stock before tackling the cylinder heads. First I made a dial for setting the valve timing. I set the dial indicator on the valves and caught some high spots on the camshaft lobes that may have gone unnoticed otherwise.

valve timing.jpg

.....then the hatches which are several layers of 1/16" brass sheet layered and pinned with brass rivets. Used a radiused piece of aluminum scrap as a bending jig for the handle. The first door knob looked too bulky so I reduced the diameter and soldered a thin bar for the handle after slitting the screw head. This looks better I think....

hatch parts.jpghandle clamp.jpgknob comparison.jpg

the diamond plate step was made from 1/16" steel sheet using an 1/8" endmill at 30 degrees every 1/4" inch. Might have been better to either tape this piece down or use adhesive because it flexed in the vice and gave varying depths of cut. Some needle filing and bead blasting brought it back to specification.

The small grab bar stanchions were quite a bit of work to make look to scale. There was also an error in height of the mounting pad and holes resulting in a trip back to the mill to slot the 0.062" holes 0.020" each (1 up and 1 down) otherwise the grab bar was out of level :( Very small parts to grip especially when milling such grabby material. I made very small cuts each time (0.010") Happy with the end result

hand bar stancheon.jpg
results to date.jpg

think i will attempt the two coolant manifolds next. I fiddled around with a bender and also mitering tube together, but think I would like a more "cast iron" look. Something like this...
Nash 25 Coolant Manifold Drawing.png
thanks Minh,
The book and plans are very good and I highly recommend it. It is edited by a engine enthusiast as well, so the layout makes sense.

Coolant manifolds

it really helped to draw the manifold using the computer. I was comparing the part to a photograph in the book of an engine at the Coolspring Power Museum. I had some 3/8" brass square stock that was very close to dimension so I started by sawing up pieces. I'm making enough for the lower manifold and the future one up atop the cylinder heads. Silver brazed the rough shape, but left the flanges off so I could radius the inner sides. Drilled the passages to a size that I had brass pins for to index the flanges later. Its a fairly deep hole, but used lots of compressed air to keep the chips clear and it didn't wander that I could tell.



Then I hand profiled the edges to give it that cast look. Here's where the computer model really came in handy. I was able to use appropriate fillets to match the end result. Then I turned a round flange and soft soldered them onto the manifold using small brass pins covered with the paint pen. This time the paint didn't keep the solder from sticking and had to redrill, but they are brass so the drill didn't wander. Maybe a dissimilar metal would be better, but they would be more likely to scrap the part redrilling if they did stick.

Drilled and tapped mounting holes and decked the gasket surfaces. Then a short time in the sand blaster and we have a very good representation of what was drawn yesterday. Note that the flanges are rotated in the plans so as to provide access to the 0-80 screws. I have seen both ways on other models. I'm using slotted pan head screws so this was the way to go. Very pleased with this small success and can start on the cylinder heads now.🙂

Cylinder Heads

Like the other parts of the engine, we deviated from the plans on material choice for economy. The cylinder heads are water cooled with a cavity just above the piston taking water from the cylinder jackets and then leaving the top of the head to go to a cooler. They also have 14 bolt bosses. All this is done by fabrication and silver brazing.

I started by sawing and squaring up a scrap of 1" hot rolled steel plate down to dimensions and drilling the head bolts. Attempted to recess the bosses by plunge cutting a 7/32" carbide end mill, but it didn't like that and promptly removed all cutting surfaces from the end mill. I opted to use a regular drill bit instead. I made several bosses real quick to verify this would work okay. Then we cheated a little and removed some of the material to save side milling later. The rotary table work was next and then the round overs were done (3/8" radius). The 1/4 hole used for the radius will become a spark plug boss later on.


The heads were flipped over on the rotary table and secured thinking that we would continued side milling to remove the cooling cavity material. This was taking too long and the boring head was brought out. Much much faster. After the initial cavity was created the table was moved in x direction to hog out the rest followed by an 1/4 endmill traveling the perimeter. The small step is a ledge for a divider plate which was made with the 1/8" off cuts from the heads.


The last thing before brazing is to cross drill the coolant hole from cavity to cylinder which is a right angle, so a plug is needed to fill the left over hole on the radius. That's why there is a round bar in the setup for brazing. The plug will just keep pushing out while heating. I tried several low temperature fluxes and solders on scrap, thankfully, before opting to just use diluted JB weld to secure the bolting bosses into the head. I couldn't get any of the solders to flow nicely giving the desired fillet. Acetone mixed into the JB works well.


There are two more steps left on these heads. Need to drill/bore the spark plug area out and make a press fit recessed boss and drill and tap the coolant passages. The plans called for store bought spark plugs that apparently have an uncommon #10-40 thread. I had a good time making the smaller #8-40 plugs for Steve Huck's Demon V8 and chose to revisit that process. Most people that see the completed 5" long V8 engine in my office at work are amazed about the tiny little spark plugs, and probably don't really appreciate the precision involved in making other miraculous things like miniature valves, camshafts, piston rings, gears etc.

I have 1/4" hex bar, 0.029" music wire and 1/4" thick Corian so we'll build on that.

Does anyone know where to purchase that braided cloth old timey wiring for the spark wires?
Excellent progress on a nice engine - thank you for sharing your journey.
Does anyone know where to purchase that braided cloth old timey wiring for the spark wires?
PM Research lists both 14 and 16 gauge cloth insulated wire on their website in case that is of any interest.
Thank you Cwelkie, I didn't know that PM Research sold wire. I have built their horizontal boiler and feed pump. Very nice kits.

I do enjoy sharing the work here. I have not met anyone local that shares this interest, all doctors and lawyers and such in the neighborhood.

Spark Plugs
two of the difficult things to making your own plugs are soldering the brass tip to the electrode wire and drilling the flat bottomed hole for the gap bridge in just the right way. I made four plugs thinking that I would mess this up along the way somehow.

Dimensions are critical so I made a sketch. Changed the 0.149 to 0.156 so I could flip the corian insulator over and drill the other side. This bit is so tiny!
Very small advance/remove/redo over and over.


Made the steel parts first using 1/4 hex bar. It machined like 1214L but it was leftover so not sure. Need a small threaded collet (upper RH corner third pic) so one can flip over after parting and drill the recess and blind hole. I threaded 10-36 instead of 10-40 and it seemed to work out okay. The difference between major and minor threads is what's important. If you don't leave enough thickness, then they break off when tightening and removing. Its always fun to see if the blind hole is drilled correctly as you remove the sides and end of the bridge in the mill. I used a very sharp carbide mill for this and 0.005" cuts. (arrows) sides first then the bridge. I did need to use a diamond file to even the gap up to be clean and consistent. This means the dimension cannot be less than thickness of your thinnest file plus thickness of bridge.


I already had a nice 0.020" grooving tool that clamps an #19 exacto blade flipped upside down and sharpened. The three 0.010" grooves help the wire boot grip the end. They look cool also.


then I pushed the insulator into the steel body with a dab of JB weld using stacked feeler gauges at the bottom. I tin the electrode wire after sanding it with 400 grit. I could not get good results if you skip this step. Slide the brass tip over the other end and use a electric solder gun to heat and pry the brass up over the tinned parts. Sand off the end and fit each electrode into the bodies using an abrasive wheel to adjust the gap. Finally epoxy to hold in place. Haven't tested them, but I think we are good to go. I also made wee little copper washers.

Very satisfying job and saved $120 on this job that I can put towards tools or something else...

The cylinder heads are complete now and awaiting fasteners and gaskets. I made the top cooling manifold exactly like the lower one. I tried graphite from pencil lead on the locating dowels and they still soldered themselves in the bores.

heads completed.jpgPedestal DWG.png

Will need to elevate the engine for flywheel clearance, so I spent the morning sketching out some pedestals and surveying the options. One could follow the theme of carbon steel, or brass, plate and braze together. Thought about casting using a simple wood pattern or maybe foam casting would be easier.
The sides have a matching angle of the lower crankcase and 3 degrees of draft on the front. The feet will be added later

I had picked up a piece of 1/8" "textured" steel plate which I decide to use as it would simulate the cast iron look I was hoping to achieve. I chose to TIG weld it because I haven't used that in a bit. 105 amps and ER70S2. These welds have just the right amount of porosity to match the "textured" steel.:rolleyes:

I rough cut the plate using abrasive disc, grinder and a repurposed bed frame as a straight edge. Bed frames are hardened steel and hold up very well. I wear all the PPE and secure the piece with clamps because I've seen too many discs explode at work.

Squared up the edges on the mill and tacked the box while keeping it square. This goes pretty fast but I really should have cleaned the oxide further away from the weld if this was more important.

textured plate.jpgTIG box.jpgmachine bottom and feet.jpg

Very little machining (<0.010") was needed on the bottom to true up the box and then the 0.375" x 0.625" cut outs were milled for the future feet. I am very happy with the look so far. Bonus points to the keen observer that notices I added a hub to the crankshaft pulley (too wobbly) and recessed the faces of the cam pulley (cosmetic).

clearance for flywheels.jpg
The extra detail on the gears add a lot to the look. Your NASH is looking great.

I need a sub-base for the Merriam-Abbott (Doug Kelley design) I'm building. Something along the lines of the base you've built is just what I need. I'm not familiar with textured steel plate. Where did you find it?

Also, you've probably said, but what CAD package do you use?


Hey Chuck,

Thank you for the compliment

The "textured" steel plate is just rusty steel plate I rescued from the dumpster at work. A dry attempt at pretentious humor. I intended to practice welding on this scrap piece until I realized how important clean metal is for the TIG process. My other lame attempt at humor was referring to porosity in the weld being intentional to match the dings and divots in the metal.

Some of the joy to me when building stuff is repurposing metal and taking advantage of the inherent properties. When I built the Demon V-8 I used a piece of this rusty metal as a baseplate and oiled it to contrast the shiny aluminum parts and plated headers. I was careful not to remove the patina. For the Nash 25 pedestal, I sand blasted most of the oxide off to weld/braze together.


I'm using Autodesk Fusion 360 and love it. The home/hobbyist version is stripped down but has everything I need to "imagineer" simple parts.


Thanks for the update. You got me with that "textured steel". I have some laying around the shop also.

The rusty steel base for your V8 looks nice. I'll have to remember that.



Thanks for the update. You got me with that "textured steel". I have some laying around the shop also.

The rusty steel base for your V8 looks nice. I'll have to remember that.



Hoping to add a smile to someone using that line of dry humor. I may leave this Nash base as is because of the patina also. Still quite a way to go.

The feet were made in pairs using 3/8" cold rolled steel. I drilled the mounting holes small at first so I could use the rotary table arbors I had. Only room for one clamp so I added the third point of contact using a tapped hole and SHCS (blue arrow). Then cut in half and attempted to use silver solder and white flux to secure them. Didn't flow at all. This Kapp Zapp solder is 3-1/2% Ag so I thought it would work on steel as the $$$ Harris Stay-Silv brand. Had to use brown flux and 56% silver braze after all. Remilled the feet level on the mill.

3 point contact.jpgbraze base.jpg

The flywheels were purchased from Gary at Martin Model. I was able to talk to him on the phone, and is a super nice person and his work quality is incredible. The minimal amount of flashing is very much appreciated. $120 shipped to my door is also very affordable for this quality of casting with the detail and consistency of the finish. Looking forward to purchasing more from him on future engines.

Martin Model Website

Martin Model Flywheels.jpgminimal flashing.jpg

I was so impressed that I didn't take the time to measure the pair before fixturing one and taking it to the plan dimensions of 7.75" and 0.75" width. I verified the second one before removing the first one from the face plate of the lathe. It must have shrunken more than the first one and with my lathe setup I had difficulty with the outer layer and chatter. I estimated it would be 0.05" removed once I got past the chill, so I adjusted my target dimensions to 0.700" width and 7.650" diameter. The second flywheel outer diameter was still barely in the chill zone and I stopped cutting and sanded the rest down to remove the chatter marks. Still very pleased with the results but learned a valuable lesson about casting dimensions. I'm sure Gary would have replaced the smallish one, but I didn't want to inconvenience him or use his profits up. Got to take care of the few people left supporting this niche hobby right?

I liked the face plate setup as it was very secure and mitigated most of the ringing noise from just holding it by the hub. I may need to touch both of them up once I make the split hub inserts to ensure they don't wobble. They look huge on the little engine but I guess they are needed for this firing order. I will also attempt to make a drive pulley using the scrap 3" pipe I have. I think I'd be better off with a bit of 1214L or cast though.

Flywheels continued.....

I followed Sprocket's advice on the small split parts that clamp the flywheels to the shaft. Easier to make a square out of round. I had a short piece of 1214L which machines so nicely, I always swear I will use nothing else, until I walk past some beaten, rusting, chunk of scrap iron laying on the ground near a dumpster. Followed the plans and made it a press fit using each flywheel which were bored.


They look great on the engine and run very true. I used them to skim cut the mounting pads on the three spokes to accept a pulley. For the pulley I used a cutoff from when I made the drive wheels on my last model, the 1916 Case tractor. It is a 4 inch SCH 80 piece of A106B pipe. It machines very nicely as long as you don't try to take a small cut.


For the mounting ring on the pulley, I used a 4" x 4" piece of 1/8" CRS plate and turned it into a washer. Next I TIG welded it into a recess cut in the 4" rim. Could have brazed it, but TIG has much less chance of warpage, and I estimate less energy used to make? I alternated sectors and only welded the outside so it could be trued up in the lathe. One can still see the heat affected zones in the image inside the rim. Still need to locate and drill the mounting holes and tap the rim spokes.

I would like to attempt driving a dynamo with this pulley, but use a small DC motor and just make a "dummy" shell. Saw this one at the recent tractor show.

Raveney--I have just read thru your complete thread, and you have done a fabulous job of building and documenting it all. Very nice work and very nice write ups about it. Congratulations!!----Brian
Thank you Brian,

Appreciate the compliment and hope your knees recover quickly

Exhaust and Intake manifolds

both of these parts are made from brass with the internal passage ways cross drilled and then plugged and silver brazed. I couldn't find any small carburetors similar to what was called for on the plans (3mm bore size) so I settled on a Traxxas 6 mm bore

Hope it works okay. I removed the throttle arm and made a new one from brass that I will secure using a secant arm, and perhaps build some kind of filter housing. I also removed the needle valve plastic cover.


I left the flanges round for the water cooled exhaust manifold and cut them and drilled after silver brazing so I didn't need to index the holes. That worked really well. I need to order some of the unmachined cast elbows from PM Research as others have done to route the coolant to and from the manifold flanges. The engine is pretty well finished now. Accessories like screen cooler, water pump, fuel tank and ignition are all that's left. Easy to get in a rush now, but I'm going to slow my roll and try to do a nice detailed representation of those items.

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