RE: Lathe for conversions
 

Capt'n, they have to be exact. Anything else gives you a valve seat type contact, IE a knife edge band, with a lot of wobble. It doesn't take very much difference either. You can do the math. If you are within 1/10th degree, you are probably OK. One more thing, when cutting a taper, it takes very little on the cut to make a big difference in the final seat along the shaft. IE, a couple thou over size and your flywheel will be rubbing the crank case. And, you can't shim it out.

Don

RE: Lathe for conversions
 

Capt,n check your email. I am sending you 5 PDF documents on taper turning and face plate work.

Tim

RE: Lathe for conversions
 

Thanks Guys (Tim & Campgems) for the help. That is why so far I use the center of the flywheel for a good taper lock-up. I may try to cut a taper into the screw on prop adapter....but to me it is not the best way to it. Just don,t know. Best Regards, Capt,n

RE: Lathe for conversions
 

captinjohn
Just what was the goal for the flywheel you posted pics of?
I have tried to do a taper as well and found I lacked tools and skills. I was not trying to true a flywheel but to get a useable 'backiong plate' for another hub part. I found the magnet to be ceramic inside of layered steel. UCK. I used a new crankshaft, to mount the flywheel.

RE: Lathe for conversions
 

mikenlapaz: It is a flywheel for a Toro (GT25) and I was just making clearance for my adapter to seat against flywheel. I wanted also to keep this new bored (enlarged) hole in center of flywheel. I seen a photo of a adapter made for same engine, but did not like the taper that was made on adapter for clearance. I am getting a couple of small boring bars....the boring bar I made will not go deep enough. Capt,n

RE: Lathe for conversions
 

Would something like this work on your crank and flywheel?
http://www.rcuniverse.com/forum/m_35...tm.htm#3543665

RE: Lathe for conversions
 

Yes the TOPCAT adapter looks good and does work. I just want a strait- full contact adapter. When I get the right tooling ...thats what I will make. I do think the knurling on both ends is a good idea...along with a good thread locker or locktite. I sure notice the weight of the Echo seems to be a lot lighter than a Toro engine of about the same cc. Best Regards Capt,n

RE: Lathe for conversions
 

captainjohn,

Setting up to turn an inside taper with a compound cross-slide:

You might try chucking the flywheel with the large portion of the taper facing your tailstock. Check / adjust the concentricity of the tapered bore with a dial indicator, rotating the flywheel by hand. Once you are certain you have the tapered bore aligned set your cross slide compound angle using the dial indicator on the inside surface of the taper (using the inside surface parallel to the bore axis). Lock down the cross slide compound at that angle. Now you can remove the flywheel and chuck your bar stock and cut your taper into your previously bored / drilled hole. Stop cutting when the outer edge of the hole is the same diameter as your crankshaft major diameter.

Another option would be to get a drill bit the same size (or slightly under) the major diameter of the crankshaft. Then grind the bit point to mimic the taper angle (determined as above or discretely measured). Mount the bit in your tailstock and you're ready to make tapered holes all day. This would be a really great option if there is any commonality of crankshaft dimensions (major diameter and taper) among some of the engines.

RE: Lathe for conversions
 

foamcut: The option of grinding a drill bit sounds like good one. I know a tool grinder that is very good at making and sharpening tools. That is his trade. I will see if he can redo a drill for making a good taper. Thanks for a good idea. Capt,n

RE: Lathe for conversions
 

Capt,n I think it would be better to have him grind an old endmill to the angle/ I had one ground by a local guy here for another job I did. Worked well and it is much stiffer than a drill would be. Either way the lathe has to be setup and adjusted as we have discussed here in the past or your bore will be off.

RE: Lathe for conversions
 

captainjohn,

If you know a tool maker he might get some business from the folks in this forum.
You might mention it to him as a source of opportunity.

The last bit I had specially ground (to a shoulder point with a pilot countersink) cost me $40 at a local tool crib.

RE: Lathe for conversions
 

I will see what I can do...the tool-grinder guy is quite busy. I cannot promise anything! Capt,n

RE: Lathe for conversions
 

Captin, I have a reamer that was made to fit the taper and shaft. I dont know of any other engine that has this taper.

Keith
BME

RE: Lathe for conversions
 

Most small lathes lack the rigidity to use a tapered reamer to make bores in hubs....Best way is use the cross slide with a boring bar, and patience....;)

RE: Lathe for conversions
 

Keith: How many Echo engines have the same taper as this reamer. If it only fits the Model 2400T it may not be much use to me. How about flwheels that fit the 2400T engine. Do you have those. Also how many Echo flywheels interchange in the 21=25cc range. Thanks Capt,n

RE: Lathe for conversions
 

RCIGN1: What model of boring bar would you suggest? Will this work? Capt,n

RE: Lathe for conversions
 

Just think...the pistons for the worlds fastest Indian was machined using the Lathe in this photo. Burt must have been a great machinest and even better at engine engine conversions. Much better than the average bear!!!!! Capt,n

RE: Lathe for conversions
 

captainjohn,

Check out Smartflix.com. They've got a great selection of instructional vids on lathe work. You can rent them rather than buying them.

RE: Lathe for conversions
 

foamcut: Thanks for the tip. I hope more people post more Lathe set-ups here from time to time. A photo is worth a thousand words. Capt,n;)

RE: Lathe for conversions
 

Hello captjohn,

Here is a web site you might be interested in or could use for making parts for the echo. It is as follows:

http://tech.flygsw.org/echo_conversion.htm

George

RE: Lathe for conversions
 

oldtimer: I just got done reading the Echo site you gave us. Very nice. How would I email and get more data on how he done the prop adapter. Sure would like to see more photos on that. Capr,n

RE: Lathe for conversions
 

You put that echo next to my 23cc tanaka and i don't think you could tell them apart. Both are great engines.
Ken

RE: Lathe for conversions
 

I got my boring bar (3/8 shank) and made a holder for it. I took some 1/2 inch square stock and drilled a 3/8 hole through it. Then cut a slot on one side for the clamping action when tool post screws are tightend. Works great! I was able to bore the hole to dia I wanted without touching original seat where flywheel washer and nut go. By shimming and drilling with lathe , I could keep tool holder on center. Here is a photo. Capt,n;) P.S. This flywheel is for a 25cc GT= Toro

RE: Lathe for conversions
 

Congrats on the progress Capn.

Now practice doing some tapers.

Have fun,
AV8TOR

RE: Lathe for conversions
 

avator: Thanks for the reply. It sure is hard finding all the tools you need or want at one place. So its a job looking for lathe tools and sometimes you pay a lot more than you want for shpping. One item here and there does cost more. I did my first taper with the same boring bar. Here is a photo. Capt,n;)