Ignore this topic

[Tin Falcon]

Alex et al:
A few real basic rules for scaling. Linear measurement is directly proportional. Areas are proportional to the square and volume is cubed. So as an example if you start with an engine of 1/2" bore the new diameter of the bore is 1" . But the same amount of air or steam pressure exerts 4 times the force on the piston. It will produce 8 times the power and consume 8 times the air or steam and use 8 times the material by volume therefore mass or weight. Potentially it could be 8 times the material cost.

Now if we go the other direction and make it half size the bore becomes 1/4"
the force exerted on the piston is 1/4 of the the original engine . the power air /steam consumption volume and weight will be one 1 /8 th of the original.
Also keep in mind that the smaller the engine the more important fit and finish between moving parts. This become a concern. A higher percentage of the power is used to overcome friction and there is less usable power left over.
For a first engine 1/2" to 3/4" is a good size it is more likely to run the first time without a lot of run in.
Yes my first engine completed was 1/4 bore the second 3/8 bore that is before I knew better.

Scaling can be helpful in converting metric to English, Like I mentioned above to increase the size of an engine by making 1 " = 32 MM instead of 24.5 conversely making an engine approx 3/4 scale makes it easy to go from metric to English measure make 1mm = 1/32 of an inch . 1 mm is really 1/25.4 or if you want to scale it up make 1 mm =1/16. by scaling up approx 1-1/2 times So this type of scaling makes the numbers come out even
Tin

 

[lugnut]

I tried something today on the cylinder for the little engine I’m building. I used a brake cylinder hone to clean up the tool marks. It worked real well and left a nice, smooth, cross-hatched finish.
Hope it works
Mel

 

[hitandmissman]

I would leave it the way it is. Just my thoughts. Gotta make that one myself. Looks good.

 

[lugnut]

Kenny here is a link to great site showing the engine.
http://www.geocities.com/~rrice2/my_engines/farmengn/hayseed.htm
Mel

 

[loggerhogger]

Cole's Power Models has one. www.colespowermodels.com

 

[Jack]

I think thats neat or as the kids say now a days "It's the Bomb"

I'm going to start on one in the next few days. so be prepared for some questions, I'm sure that I'll get stumped somewhere along the way.

 

[lugnut]

This evening is the first time that I have seen this section. I'm assuming that it’s only visible to the moderators. Looks like a great idea, now all I have to do is find something of value to write here.
Mel :roll:

 

[Tin Falcon]

Rick :
A good point. I used to think it was silly getting MSDS sheets with drill bits.
I have very seldom seen a machinist using dust mask to sharpen tooling. Even in the US Air force shops the land of safety double eye protection is stressed for grinding but not respiratory protection.
As for using a shop vac a great Idea. I have a clean stream hepa filter in mine. they cost about $25 but will last over 5 years with proper care.

Proper ventilation in the shop is important. I have to deal with breathing issues. My allergists advise was this. Set up an exhaust fan! " Dilution is the solution to pollution."


Tin

 

[the engineer]

hi guys and gals i appreciate what you say i have cerable palsey and as i have got older the falls are more frequent and hurt a lot more it seems :cry: but i have made a deal with the wife that i will only go to the workshop when she is home so she can check if im ok we have an intercom setup that she can hear me pottering around and can check up or come out and see if all goes quiet or a large soft thud is heard followed by a groan or !@#$% its hard when she now works sat and i work normal work days but i get out when i can or if im just cleaning small parts etc they come inside where im with the family
the boss at work worries all the time which irks me a bit as im the only one in seven years not to hurt my self at work
but i still love my work and life cheers hope i get to know you al better in the comming days

 

[lugnut]

A sign at the entrance of the large machine shop: Warning to young ladies: If you wear loose clothes, beware of the machinery. If you wear tight clothes, beware of the machinist. :roll:

 

[compound driver]

Hi
also worth remembering carbide end mills can shatter. yup had one do it. It hurts more pulling the splinters out than when they go in!

Cheers Kevin

 

[compound driver]

HI John
The twisted brass on a showmans engine are called Olivers short for oliver twist.
Most if not all are hollow with a steel stud all the way through. My mates engine Respite has the same I know this as we replaced the rods a few months ago.
The brass olivers were some times cast but mostly twisted after annealing.

Cheers Kevin

 

[dparker]

John: You might take a look on the Home Shop Machinist and Machinist's Workshop BBS and look at Evan's posts of a few months ago. He did some twisting of metal for some porch railings and gates that looked pretty nice and may be of some help or ideas for you. That "threading that you did really looks nice, I can only imagine it would be quite a stress riser to machine. Good work! Don

 

[ronm]

When I first got my lathe, 12" Craftsman, I had a Chicom cutoff tool holder & the lantern toolpost...Parting off was almost impossible...the Atlas is not the most rigid thing ever built anyway, & it was an ordeal that made me grab the hacksaw whenever I could. I took to leaving the belts loose so they would slip instead of buggering up the whole setup when the tool dug in; not if but when. Finally, I got a Yuasa quick-change tool holder set, it included the parting tool holder. What a difference! It's so much more rigid, there's no comparison...parting off is still not my favorite operation, but at least it's not a wreck waiting to happen.

 

[ed miles]

This problem faces those of us who work alone in our shops, and we are not as fast as we used to be reacting to a hazardous situation. Dropped a rotary table on ones foot, tripped on the edge of a fatigue mat and fell or worse. The MRO magazine this month has a battery operated alarm unit that is worn by the person. If the person stops moving the unit gives a loud audio alarm and then sends a signal back to the base unit up to a half mile. If the base is manned, the active response is initiated by the base person. It can also be connected to a auto dial phone system for remote response by other safety or for us retirees a family member. No price stated but I have sent for more information and will post it as soon as it arrives.

Ed

 

[peteski]

Not only can end mills bite while in a milling machine but they can do alot of harm sitting on your bench. When you get milling cutter resharpened they come back with a plastic coating on them to protect the cutting edges. I seen a guy grab the coating with one hand and the end mill with the other hand and pull. The sharp edges cut through the coating and his hand, 35 or so stiches later he came back to work. I might have been a newbie and at my first machine shop job but even I knew better than that. That was 30 years ago and I have all ten fingers and they all work. Must have been awake in class when they talked about safety. Use a 6"metal scale or even a nail to remove the coating, save the hands and fingers for model building. Peteski

 

[Jack]

The plans are available right here on this site, in the PLANS section. Just follow the link to the plans they are a PDF so that you can print them out on any printer, there is even a link to video of the engine running along with hints from other builders.
Today I made the ignition cam and installed the points and condensor, tommorow I am going to attempt the exhaust cam if I can figure it out. Photos at eleven

 

[Seanol]

I was working on a motor that was running mechanical fuel injection. I was dependent on O2 sensors on the Dyno for accurate air/fuel ratio. When you use race fuel with O2 sensors (leaded fuel) they degrade quickly.

One way to tell if they are working is to use propane in the exhaust (open headers) to see if the reading goes rich. You do not light the torch, just use the gas. Well, I could not get a reading. This torch had a bad igniter on it so I placed it up against my palm and pulled the trigger to see if I could feel the gas pressure.

Yep,the one time the igniter decides to work! I had a 2nd degree burn on my palm about the size of a Susan B. Anthony coin for about 2 weeks.

On the plus side, if you ever have a burn, Spenco makes great bandages that help heal and prevent scarring. No financial
interest, just a satisfied customer.

Regards,
Sean

 

[bob ward]

Have a word to the guys or trawl the archives at www.backyardmetalcasting.com
There is a wealth of experience and information there.

 

[lugnut]

I bought two buzz coils (Model "T" FORD) on eBay a while back and have had a ball playing with them. By setting up the test stand shown on that web page I was able to produce a 3/4" spark that I sure wouldn't want to touch. The Ford model T had 4 of these, one for each cylinder.
Mel