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There are no stupid questions? Boring small cylinders in my garage..

poppanitrous

Plastic
Joined
Sep 7, 2011
Location
port orange florida
I am a 1st year student working with "HAAS" C.N.C. programming at my local college's vocation program. However i wanted to get something for my garage off craigalist or a chinese version of a Bridgeport mill (which was where i am origionally from BPT/milford-CT ironically).I have heard that the new chinese stuff if maintained and trammed often can be accurate enough for my dirtbike motor needs.

The work i want to do is maintain my motocross bike i race. What milling machine or even a press can i get away with using a boring bar for max stroke/bore around 80mm. I want to be able to bore and hone my dirtbike and atv cylinders and possible learn to cut valve seats. first and foremost what is the most cost effective machine for me to invest in used and tooling to set up for boring small engine jugs?

Included please, tramming tools, vise, everything i would need besides torque plates for the jugs since i am making those on the HAAS in school this semester.I look forward to the exponential amount of information on this website and forgive me in advance for my ignorance if i am using the wrong nomenclature on tooling etc.


thank you gentlemen,
Vincent
 
There are no stupid questions?



If that were honestly the case, then there would be no :skep:, :dopeslap:, or
icon_doh.gif
.


--------------

Think Snow Eh!
Ox
 
A) Your heading is wacky and may get your post locked. At the least it opens you up to responses like the above which was my first thought but Ox beat me to it. :D
Not sure if you can change a heading but if so change it now to something like "Help boring small engine cylinders" or the like.

B) Don't mention ummm...... "that other country". That just raises heckles here.

C) Why?? The machine is only the start of the draining of your wallet.
Tooling, fixtures, and gauging to do this right will dwarf the machine cost.
Unless you are going to do lots of cylinders for other people you are better off going to someone who has the right stuff on hand. I have a fairly complete shop and I design and build this tooling for the big companies but when I need to sleeve and bore one of my toys I go across town to somebody who does this for a living.

If you really want to you can do this on any cheap mill, even (gasp) a hobby mill, but be prepared to scrap a few while you are learning.
Boring, honing and seat cutting is mostly about having the correct tooling and measuring equipment.

I admire your enthusiasm, but sometimes it's just easier to go outside to "get er done".

Bob
 
+1 Carbide Bob, Nothing like the right tools for boring cyls, a china BP clone ain't it. the only way it pays to bore cyls is to bore a lot of them. you will not be so happy boring a lot of cyls on a BP. If you want to bore cylinders get a boring bar.
 
First you need a way to mount the blocks so you can level them. Then you need a VanNorman boring bar or equivalent. One nice setup I saw had a VanNorman mounted on the ram of a old B'port.

You need dial indicator you can mount to the boring bar to tram it in and a three point dial bore gage. Ridge reamer, hones, press for the doing the sleaves, standards, cutters, a way to sharpen the cutters, plus a lot of tooling I probably missed.

Then you'll probably want a mill to cut the various mounting plates and adapters you'll find you need; and a large mill it will need to be if you want to do a good job of facing those heads.
 
I've had people ask me to bore out their buddies ATV or bike engine, I always say no as its not worth it at all,a few years ago I called the place in town specialized in that stuff and was told $49.95 honed and all, doubt it went up much since.
 
I wouldn't even try to bore a single jug on a mill. One thing, I don't think you have enough travel, another thing is mounting that thing up to the table and high enough so the boring bit can go out the bottom.

The right way to do that would be with a Rottler boring stand for exactly that type of work. You could probably hone the cylinder in your garage after someone bores it for you, but for the price it just isn't worth it.

Having a mill in the garage would be great for fixing broken parts on the bike, also making things stronger and lighter can be done on a mill.

I'd probably give up on the bore and hone idea. That's what I do and I have a lot of money in machines that do just that.

Mm
 
Boring, with 'normal' shop equipment, best done on a lathe. Make up a fixture to bolt the cylinder to, make a truing cut on it whenever you put it in the machine to use it.

Honing, you absolutely *have* to have a Sunnen hone. A ball hone, or spring loaded 'cylinder hone' will never give you the roundness and straightness you want.
 
A quality small engine shop will be able to give you results that far outpace what you could produce in a garage machine shop unless you invest lots and lots of $$ and tons of time actually getting past the learning curve including scrapping the part, siezing the piston, bad valve seating, and on and on ad nauseum. The things you really need to know are not just the things you need to have, its how you use the tools you have and no one here can give you that practical experience as the statement "practical experience" is self defining. Good luck to you though, everyone here did get where they are by scrapping a few parts along the way might I also add, there will be others. Like my dad used to say, "If it aint scrap we can fix that"
 
Vincent,

You are in Port Orange Fl. a stones throw away from Daytona while I cannot name a specific shop I know there is one in Daytona that will do what you need for probably less than $100.00 much cheaper than a Bridgeport or a clone and it will be right the first time keep up your studies read what is posted on these forums and you will be much farther ahead and still have money in your pocket for other things.

Scott
 
i've bored, decked and o-ringed lots of 3 and 4 cylinder blocks on the crusty old bridgeport, not a problem as long as the machine is reasonably tight and the 5" quill travel is enough.

BUT, look at my location, shops that do this kind of work here aren't a dime a dozen like over there. you'd be crazy to drag home a mill if all you want to do is bore cylinders. if you want to make other parts and doodads then it's a different story. and anyways, aren't most modern cylinders plated or coated aluminium?
 
i've bored, decked and o-ringed lots of 3 and 4 cylinder blocks on the crusty old bridgeport, not a problem as long as the machine is reasonably tight and the 5" quill travel is enough.

BUT, look at my location, shops that do this kind of work here aren't a dime a dozen like over there. you'd be crazy to drag home a mill if all you want to do is bore cylinders. if you want to make other parts and doodads then it's a different story. and anyways, aren't most modern cylinders plated or coated aluminium?

As far as plated cylinders goes, I don't know about bikes these days but as far as passenger cars, trucks, rv's, boats, you get the idea. Everything is good old iron. If the block is aluminum, most times a cast iron sleeve will be pressed in and finished.

On some of the early Porsche's and Mercedes they ran a aluminum cylinder, it was hard and expensive to finish the aluminum properly, and buy the right rings was also very expensive. Sleeving the block with iron and finishing was the way to go.

Mm
 
Vincent,
Before you start buying machine tools, you should really look into a major drug addiction. Preferably one that can be dropped in your older age and does not mess up your body too much. Once you start down the machine collector path, there's no turning back. Plus you will probably be killed trying to move a 4000 pound machine with a motor hoist.
have fun
i_r_machinist
 
Vincent,
Before you start buying machine tools, you should really look into a major drug addiction.

I agree.

In South Florida the blow oughta be cheaper and more plentiful than non-rusted machine tools, plus you trade it to women for service work.

:willy_nilly:

As far as plated cylinders goes...
Mm

I was under the impression that all modern dirt bikes had a Nikasil plated cylinder.
 
There is a reason specialized companies build equipment specifically for the engine rebuilders.

Accuracy and constant results.

Any mill, any brand would need a strong true running spindle or you will never have a decent jug.

I have a #4 mill (16000 lbs with more travel than needed for any automotive engine), and there is no way I would consider messing with a jug.

Could it be done on a mill, sure.

Will it be round, no taper, most likely not. (exception: well versed machinist, top quality tooling)

I would assume if you are actually "racing" you would not even consider
operating with sub standard machined jugs, cranks etc. :nutter:
 
For occasional oversizing small cylinders you can lift, just get a sunnen style manual hone machine like a sunnen lbb1699. This is how most engine shops would do it. Setting up to bore a small cylinder, bore it and then set up the hone to hone it takes longer than just honing it. I do quite a few a month like this. Dont overthink it or it gets complicated.
 








 
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