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Edwards Radial 5 build thread --- PHOTOS!
- Thread starter JRaut
- Start date
Superb work.
- Joined
- Jun 8, 2021
- Messages
- 5
Stunning, inspirational work!! How much machining experience did you have before you started this project? I noticed in an earlier post you said you were a bit new to the hobby. So am I, and you are inspiring me to get out there and fire up the Myford and the mill.
- Joined
- Mar 9, 2018
- Messages
- 461
Thanks for the kind words, @Snider577 !
I've had a lathe for about 4 years, and a mill for only about 2-3 years. I did have a milling attachment for my lathe, so I was able to knock out some relatively small projects early on, but this Edwards Radial 5 is basically my first BIG project.
- Joined
- Mar 9, 2018
- Messages
- 461
Episode 29 || Intake and Exhaust Runners and Flanges
Alright, there will be two posts here in rapid succession. And a fair warning --- I didn’t take very many photos for either of these ‘episodes’. I’m frankly running out of steam a bit with the whole writeup thing, so have mostly been focusing on trying to get the job done.
I modeled up the intake and exhaust runners in Fusion mostly for the purpose of designing a motor stand that would avoid everything. But it sure does make a nice visual. I didn’t bother modeling the flanges.
I started with the intake runners. It took lots of trial and error to get the bends correct. The process that worked best for me was as follows:
1. Cut some brass tube to length. The tubes are 9/32” diameter with 1/64” wall thickness (1/4” ID).
2. Heat to cherry red and allow to cool to fully anneal (the tubes cracked when bending if I didn’t do this)
3. Clean up the ugly surface with some emery cloth.
4. Pack the tube tightly with sand. The playground sand from my backyard turned out to be a bit too coarse, so I made a makeshift sieve to reduce the maximum particle size.
5. Load it up in my newly made Hemingway Kits Tube Bender. I purchased and made the kit specifically for this job. I still need to make a bunch more mandrels for other tube sizes; I’ll probably only make those when the need arises. I used a bend diameter of 2D, which was a bit too tight, even with sand packed into the tube. The drawings called for a bend diameter of about 1.75D, which would have been way too tight; I suspect 2.5D would have been about right.
6. I used a protractor to get the total bend angles correct. (Or correct enough, anyway.)
Rinse and repeat until I made all 5 intake runners. The process was similar for the 5 exhaust runners.
You can see from the little crinkles that the bend diameter was a bit too tight. I’m not worried about it.
The drawings call for the flanges to be made of steel. I decided to CNC machine them out of 0.04”-thick brass instead. Here’s the ‘program’ I wrote for my ancient Bridgeport EZTrak.
I took a page out of Robin Renzetti’s playbook and used 3M 467MP adhesive for holding the brass sheets to a sacrificial block of aluminum. I used a gage pin to burnish the adhesive down before removing the backing.
I was nervous that the tape wouldn’t be enough to hold each of the flanges during machining. So I made up a little bushing and bolted each flange down after drilling out the center hole. Then let the CNC do it’s thing x15 plus a few extra.
A quick debur and a swipe of some sandpaper and the flanges were done.
Then I just silver soldered each of the flanges to the intake/exhaust runners while installed on the engine. Pretty painless.
Only mishap is that I accidentally threw too much heat and some of the valve springs while silver soldering, which ruined them. I’ll have a remake about 5 or 6 of them I think.
<EDIT: I also broke off a #2-56 SHCS for the intake runner in one of the heads. Damn. I sure hope I can drill it out, I definitely don't want to be making another head. I'm pretty confident I'll be able to drill it right out with a little carbide PCB endmill.>
And I forgot to get a photo of all the runners complete and installed, but I got some nice photos after I made up the engine stand, which I’ll post probably this evening.
TIME ON INTAKE AND EXHAUST RUNNERS: 19.5 hours
CUMULATIVE TIME: 459 hours
Alright, there will be two posts here in rapid succession. And a fair warning --- I didn’t take very many photos for either of these ‘episodes’. I’m frankly running out of steam a bit with the whole writeup thing, so have mostly been focusing on trying to get the job done.
I modeled up the intake and exhaust runners in Fusion mostly for the purpose of designing a motor stand that would avoid everything. But it sure does make a nice visual. I didn’t bother modeling the flanges.
I started with the intake runners. It took lots of trial and error to get the bends correct. The process that worked best for me was as follows:
1. Cut some brass tube to length. The tubes are 9/32” diameter with 1/64” wall thickness (1/4” ID).
2. Heat to cherry red and allow to cool to fully anneal (the tubes cracked when bending if I didn’t do this)
3. Clean up the ugly surface with some emery cloth.
4. Pack the tube tightly with sand. The playground sand from my backyard turned out to be a bit too coarse, so I made a makeshift sieve to reduce the maximum particle size.
5. Load it up in my newly made Hemingway Kits Tube Bender. I purchased and made the kit specifically for this job. I still need to make a bunch more mandrels for other tube sizes; I’ll probably only make those when the need arises. I used a bend diameter of 2D, which was a bit too tight, even with sand packed into the tube. The drawings called for a bend diameter of about 1.75D, which would have been way too tight; I suspect 2.5D would have been about right.
6. I used a protractor to get the total bend angles correct. (Or correct enough, anyway.)
Rinse and repeat until I made all 5 intake runners. The process was similar for the 5 exhaust runners.
You can see from the little crinkles that the bend diameter was a bit too tight. I’m not worried about it.
The drawings call for the flanges to be made of steel. I decided to CNC machine them out of 0.04”-thick brass instead. Here’s the ‘program’ I wrote for my ancient Bridgeport EZTrak.
I took a page out of Robin Renzetti’s playbook and used 3M 467MP adhesive for holding the brass sheets to a sacrificial block of aluminum. I used a gage pin to burnish the adhesive down before removing the backing.
I was nervous that the tape wouldn’t be enough to hold each of the flanges during machining. So I made up a little bushing and bolted each flange down after drilling out the center hole. Then let the CNC do it’s thing x15 plus a few extra.
A quick debur and a swipe of some sandpaper and the flanges were done.
Then I just silver soldered each of the flanges to the intake/exhaust runners while installed on the engine. Pretty painless.
Only mishap is that I accidentally threw too much heat and some of the valve springs while silver soldering, which ruined them. I’ll have a remake about 5 or 6 of them I think.
<EDIT: I also broke off a #2-56 SHCS for the intake runner in one of the heads. Damn. I sure hope I can drill it out, I definitely don't want to be making another head. I'm pretty confident I'll be able to drill it right out with a little carbide PCB endmill.>
And I forgot to get a photo of all the runners complete and installed, but I got some nice photos after I made up the engine stand, which I’ll post probably this evening.
TIME ON INTAKE AND EXHAUST RUNNERS: 19.5 hours
CUMULATIVE TIME: 459 hours
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