Cylinder Porting

aspeed wrote:There are a few brand names that are the same machine coming from the same factory.  Look carefully to see that it is the same one.  There are forums on that lathe with a big following. http://www.mini-lathe.com/   Sometimes you can get a used one for half price too.  My Taig was used and a deal that I could not pass up.  I bought a few accessories at full price though.  For metalworking machines, I always consider them to be a usable investment.  Normally you get the money back if you bought it used.

Aspped: the company I just looked at for $474 for a mini lathe was Grizzly.com . waiting for more info. I have seen the link you posted before and will review again. Thanks.

I have been "talking" with Coxaddict about how to remove the bar between the dual slit cylinders and was inspired to try it. some of the pictures focus switched from the subject to the background. I only have 2 hands, but you will get the idea.


basic dual slit cylinder


first try to remove bar, notice some mistakes. different lighting.


interior porting, 1 of 2


typical setup using magnifying light as spark protection, hard to see cylinder and rotating blade. notice GLOVES.


2nd cylinder, damage in lower corner. Tried to add SPI, but cut into edge of exhaust port. OOPS.


2nd side of 2nd cylinder, note damage. the Dremel tool was getting really hot. garage was in the 100's.

thanks for the advice Coxaddict.

happhdad

The 100s? You wouldn't catch me out there. The cylinder looks pretty good. I don't see a burr inside the port. I would use a mill, but your method is fine. I do similar stuff. I even have a magnifier just like that with a round flourescent bulb. I use dollar store 2.5 x glasses on top of the magnifier. I am getting old.

aspeed wrote:The 100s?  You wouldn't catch me out there.  The cylinder looks pretty good.  I don't see a burr inside the port.  I would use a mill, but your method is fine.  I do similar stuff.  I even have a magnifier just like that with a round flourescent bulb.  I use dollar store 2.5 x glasses on top of the magnifier.  I am getting old.

The good side is the house is in the low 80’s. And I can get some of my fun work done out there.
   The cylinder(s) were a first time test. If I do it again I will try to jig everything so I can fine tune movement, like with the micro lathe I looked at. It has a table with X-Y movement I could use for the cylinder movement and jig the dremel tool with blade to the lathe somewhere.
   Besides it’s only money.   I taught computer basics to seniors at a senior living facility for 5 years and all the money I made, $30 a day, one day a week, I saved for toys. Along the way several of the days were cancelled for holidays or at the last moment due to “meetings”, so I eventually quit because of the dishonesty of the management at the facility.
  That $475 lathe is looking better every second. I wish now I had purchased the lathe when I retired back in 2007. Then I still had access to other metal working tools like bending brake, shear cutting table, etc. I wanted to buy the tools when the company went bankrupt a few years later, but the dummy manager so it by the pound. 🤯
   Heading back to the .020 All Star Biplane wing.
Happydad

Cutting exhaust ports


3" diameter x .081" cut slitting saw

Finished cylinder

Dual port, single booster on each. Sure start cylinder with center piece removed and bottom of port lowered for SPI

happydad,  use the damaged cylinder in a vise by grinding off the fins. Then you can screw your work cylinder into the cylinder in the vise to free up your hands.  If you use a thicker cutting wheel you can make a smoother cut. I ruined a couple of cylinders trying to cut the slits on my mill! My first jig wasn't solid enough. You can use the same setup to cut the intake ports. The male or female threads can be used to hold the work cylinder depending on which end of the cylinder needs to be facing you.

coxaddict wrote:Finished cylinder

Ok. Ok. Yours looks better than mine. Now what do I do oh bee one?
LOL

Happydad

coxaddict wrote:happydad,  use the damaged cylinder in a vise by grinding off the fins. Then you can screw your work cylinder into the cylinder in the vise to free up your hands.  If you use a thicker cutting wheel you can make a smoother cut. I ruined a couple of cylinders trying to cut the slits on my mill! My first jig wasn't solid enough.

I heard that from my old friend in New Zealand about 6 or 7 years ago, but never thought I would even consider a lathe at that age, 67. What a padawan.

P.S. can’t seem to find the right blades for the dremel multi rotary tool yet. Just the thin ones. If I buy the $25 adapter kit I can use many more cutting blades. I am learning.

Happydad

coxaddict wrote:
Dual port, single booster on each. Sure start cylinder with center piece removed and bottom of port lowered for SPI

Pretty much exactly as Bernie sells as a Tee Dee Cylinder.  Very good performer.

happydad,  the Dremel  541 grinding wheel is .125" thick.  Check out their website for other bits especially the tungsten carbide ones.

Oldenginerod, since I have mostly slit exhaust cylinders I thought I'd give it a try. Real happy with the results.

Do you have a before and after tach reading? I have a slitted cylinder, and thought it went pretty good considering.

aspeed, I didn't think of doing a before and after rpm comparison, maybe I will the next time I do a Bench run. The SPI definitely made a difference. The Killer Bee runs high rpms with a slit exhaust and SPI. If I can find the right slitting saw maybe I can replicate a Killer Bee cylinder.

If Not finish m'y suggestion is try... dale kirn.. in search tool is 1 crude Drawing of tee dee modification wit référence number look now Drawing its 3 boost port on 2bypas and 1 longer the 3 boost ist finish like just extra if .???

coxaddict wrote:aspeed,  I didn't think of doing a before and after rpm comparison, maybe I will the next time I do a Bench run.  The SPI definitely made a difference. The Killer Bee runs high rpms with a slit exhaust and SPI.  If I can find the right slitting saw maybe I can replicate a Killer Bee cylinder.

coxaddict:  good to see you back. I am getting close to my goal. I have emptied about 25 boxes, cataloged about 10 boxes and still have about 20 boxes to go. I have discovered thing I thought I had lost forever. I found a brand NEW ACE RC 4 Channel KIT with everything except a battery, a frequency module and about 50 wires to connect. It was there entry into the digital age. I am pretty sure I ordered a 53.4MHz transmitter module, I am also a HAM, and can use the 53MHz band. I already have a 53.1MHz transmitter I built back in the early 1980's.

    So when does lesson 2 start in the cylinder modification series begin. I can always find time for a little Dremel tool fun. I still have everything just as we left it, ready to go.

Hope you and yours are safe and the GIANT SURF isn't too big for you. Stay safe.

happydad                              

Hope everyone is safe from all the fires and bad weather. The ocean is like glass until the wind picks up around 9 A.M.. Been too busy repairing my roof and painting my house. The good thing about that is my wife lets me buy more tools that I tell her is needed for the job. Those Milwaukee brand M18 cordless tools are the bomb! When we start to have rainy weather then I'll stay indoors.
I have a lot of .049 parts and engines both early and late and have noticed that all the early thin wall cylinders including the number 2 cylinders have a taper bore. I like the pinch at the top as I think it makes for easier restarts when hot. Now the thought of modifying those number 2 cylinders come to mind. I have had success milling a second intake port but will take it another step by adding booster ports. I will however need to get a better tachometer to gauge the results.

I wish I had those old stock COX parts to play with.

If you have a smartphone with Android op system, you can download from Google Play the Rpm gauge free app, that is an audio based tachometer and is as accurate as any optic version...

Thanks balogh,
I'll check out Google play, my phone is taking over my life

You did a superb job on the cly. coxaddict I have never cared much for the slit cylinders myself .

Thank you getback,
Slit exhaust cylinders come in a variety of port configurations. There's a lot of experimenting that I want to do. Maybe removing the slit but shortening the piston to allow sub-piston induction?