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| johnreid |
What is the thread size for SE3 eccentric?I have been trying to figure out why my SE3 doesnt run all that well when I noticed that the eccentric moves on its shaft thus changing the timing all the time. The screw is down in the eccentric and seems to need to be removed with a drill or something ( not the problem as I can do that ) However I want to know what size screw I need to get before I mess with it, I might need help finding a replacement screw too as I fear it is a thread that isnt available locally, or is it?.
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| rangerssteamtoys |
I dont think that that is an eccentric, I believe its a crank. Or crankshaft, an eccentric is the this used on slide valve engines to control the slide valve.
As for your problem, soft solder it 
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| johnreid |
True crank, but to define eccentric it is an off center eccentrical disc.
Soldering makes it hard to adjust if needed later. If a fine tuning is needed, the set screw or grub screw is the superior way to go. |
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| Mamodman123 |
I wouldn't solder that, I'm not sure it would stick to the crank shaft anyway??
Its a grub screw not sure on the size unfortunately as I don't have the tools to measure it 
John when did you get this SE3 I think I missed it?
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| johnreid |
I got it from Oldstuff back in May I think. I had another that I traded along with a Cast Base Jensen for another engine. The one I traded off was like new and seemed to run better, but now I know why.
I dont have any taps that small and thing that a screw would be less expensive than a tap. |
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| IndianaRog |
John, I'd try a few misc. bolts in the grub screw's hole...if you find one that seems to work, perhaps local hardware store can match the thread and give you (sell you) a proper grub screw. Otherwise, just cut and slot a bolt that works.
Once you get something that grips properly, and the timing is right (tad off 180 deg. works best for me)...I would clean the threads well with meths and put a drop of locktite on grub screws. Removeable if needed, but they won't loosen up on you. |
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| Mamodman123 |
Have you tried the one from the pulley? | ||
| johnreid |
I will, then what size is it? I think I still need a replacement screw. The local Hardware Store will not special order screws in quantities of less than 100, no metrics, paid in advance. | ||
| IndianaRog |
I was just thinking you find ANY screw, metric or English that will fit the threads and give good grip...then have hardware store match it if they have one in grub screw form. Personally I would take a dremel cutoff wheel to a screw that works and cut to length/cut a slot and you are home free. You are right, no one is going to custom order such a thing for a one off! | ||
| rangerssteamtoys |
If you have a tap and die set.... use it.
If you dont, then go get a cheap one. Find a screw that almost fits and tap it so it will. You might also be able to just find a screw that almost fits. Like a Jensen screw, and just jam it in the hole. Brass is soft so it should self thread. Throwing out good and bad ideas here
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| johnreid |
I was kind of wanting to have the screw on hand before I drilled it out, the head is below the brass surface, recessed and a small jewelers screwdriver will not purchase grip to screw or unscrew the screw. I guess I will have to drill it out and find a small tap. This one goes on the shelf for a while. | ||
| IndianaRog |
John, can't you take the good one out from the other side to use for sizing?? | ||
| johnreid |
Only one is threaded, I will find out soon. It is just that this one is in such good condition I hate to modify it, just being stubborn I guess.
I am going to try some locktite on the shaft and see if it willnot at least run better till I get this sorted out. It isnt like I dont have other engines to run. I go in phases, I seem to run one a lot for a week or two, thin I pull another out and run it. Tomorrow the big Fleischmann and a Bowman. |
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| Roly Williams |
On mine it's 6BA and I assume it's original.
BA screws are available in the US but noy in your local supermarket! There are loads of suppliers on the internet and some go on Ebay occasionally. An Ebay or Google search should find somebody in US. |
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| seven.mpd |
I would agree with Roly Mamod tended to use a certain range of screws 6BA being one of them. | ||
| steamyjim |
Ranger is right. It's a crank  An eccentric on an engine is what operates the valve gear on a fixed cylinder engine
I would agree at 6BA. Aulthough i havent tryed it on an SE3 Mamod seemed to use a lot of 6BA bolts its sort of their standard size i think |
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| spatial_pan |
I would be in the same position as the author of this thread in that I'm tooling up over a period of time and don't have every tap or die or tool immediatly at my disposasle. It is a mantra of mine that the right tool for the job is the best way to go although I realise that modellers are resourceful and can often find rematkeable work arounds for many problems. Personally i would regard purchaising a suitable tap (6ba) to be an investment as they are only a few pounds and you are almost for certain gonna need it again in the future |
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| johnreid |
I fear that the price of a 6BA tap and Die ( I wold need the die to make a grub screw ) would cost me almost as much as another SE3!
A fellow forum member has offered to help, I do like to keep an engine original when I can. I know how people complain when they buy one on Ebay and it has been mucked with. |
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| steamyjim |
Christ does it cost that much in the US 
For a 1/4" 32 TPI BSF tap and die i needed recently from 'Tracy Tools' it was just under £10
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| steamyjim |
Here you go John...
Price of BA tas and dies from 'Tracy Tools' Your looking at £4.50 for both
http://www.tracytools.com/tapsanddiesba.htm |