# drill rod?



## Aydelott (Aug 25, 2012)

I read somewhere to use drill rod for my piston an valve rods so I was looking them up an I guess there is two different types water and oil hardened I guess that's the way there quenched but witch type should I get an if its hardened will I still be able to run a die down the ends to cut the threads thank you for your help.


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## chucketn (Aug 25, 2012)

You are right in that oil hardening quenches in oil and water hardening in water. I would do all required machining before hardening.

Chuck

edited to correct typo


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## Aydelott (Aug 25, 2012)

if i buy this drill rod its already hardened so i was just wondering if you could run a die hardened metal. Or anywhere  get rod not hardened?


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## chucketn (Aug 25, 2012)

Drill rod is not hardened when you buy it. You machine it to your requirements and then harden and temper as required.

Chuck


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## Aydelott (Aug 25, 2012)

o ok well i look in to it more thats what i understood thank you!


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## Brian Rupnow (Aug 25, 2012)

It seems unusual to me to be making a piston from drill rod. Valves, yes, but a piston??? what kind of engine is it.


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## rkepler (Aug 25, 2012)

Aydelott said:


> I read somewhere to use drill rod for my piston an valve rods so I was looking them up an I guess there is two different types water and oil hardened I guess that's the way there quenched but witch type should I get an if its hardened will I still be able to run a die down the ends to cut the threads thank you for your help.



A valve face can use the hardness available in drill rod but I can't see it being necessary in a piston.  If you hadn't mentioned valve rods I'd think that the point was the roundness of drill rod but that's available in other more easily worked and lower cost materials.

So along with the mention of threading I think you're looking for material for some other application than a piston?


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## Aydelott (Aug 25, 2012)

No I was told to use it because of its roundness its for the piston Rods the pistons are brass  I tried to make the rods but I kept having a .002 taper over 6in IM open to other material if you have any opinions!


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## Brian Rupnow (Aug 25, 2012)

Sorry, I misunderstood. It does make a bit more sense if its being used for a piston ROD as the rod passes thru a "gland" with packing in it to seal any escaping steam or air. Although I have always used just standard cold rolled steel rod for piston rods and seemed to get away with it.


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## MarioM (Aug 25, 2012)

Checking an engine plan from Philip Duclos, it asks for a valve push rod made of CRS N. 5D x 1 3/4" finish nail.  Does anybody knows what it means??

Mario


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## Aydelott (Aug 25, 2012)

CRS is cold rolled steel i dont know what the rest means


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## Aydelott (Aug 25, 2012)

The reason I want to use drill rod is every tolerance on my engine is under .001 an I would like to get it perfect but when I Google drill rod its all hardened tool steel where can I get it that's not hardened


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## MachineTom (Aug 25, 2012)

A 5D is the size of a carpenters NAIL, so a 5D Finishing nail is used for moulding and the like. IMO it means any old piece of steel will work.


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## Aydelott (Aug 25, 2012)

crs is cold rolled steel i dont know what the rest means sorry The reason I want to use drill rod is every part on my engine is under .001 an I would like to get it perfect but when I Google drill rod its all hardened tool steel where can I get it that's not hardened


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## d-m (Aug 25, 2012)

I would go to speedy metals or on line metals you can buy it by the foot in the sizes you require it will come Not Hardened. I always try to get some extra stuff as the shipping won't change that much if you add say some Hex rod or leaded alloy. I Just got some hex rod for a small job when I checked out the shipping for just what I needed was just under $20 bucks. I added 3 more sticks one 1/2 drill rod and 2 different sizes of leaded alloy and the shipping was only about 3$ more .
Dave


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## Tin Falcon (Aug 25, 2012)

CRS Common abbreviation for cold rolled steel.  5D abbreviation for 5 penny nail. somewhat antiquated term originality the price of a hundred nails. 
nails size chart here





finish  is the head style of the nail.


I think what tom said sums it up . If the material is a nail  any similar size piece of steel will work.

Tin


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## Aydelott (Aug 25, 2012)

The reason I want to use drill rod is every tolerance on my engine is under .001 an I would like to get it perfect but when I Google drill rod its all hardened tool steel where can I get it that's not hardened


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## rkepler (Aug 25, 2012)

Aydelott said:


> The reason I want to use drill rod is every tolerance on my engine is under .001 an I would like to get it perfect but when I Google drill rod its all hardened tool steel where can I get it that's not hardened



All of the drill rod I've bought has been fully annealed, about the only source of hardened drill rod would be a drill or reamer blanks and even then I'm not sure that it would be fully hard.

From experience if you make an engine to that sort of tolerance it will be very difficult to run.  If you're a little over in the rod size and a little under on the bore they just won't fit.  If the sizes are dead on and the bore is a little crooked same problem.  If a rod is a little bent (as metal is supplied) it'll jam at one end or the other.  

A steam engine which is loose at most spots and tight at only a few will run like a watch.  Too loose everywhere and it'll run, but noisily.  Too tight all over and you'll have trouble turning it over with a wrench. The real art here is knowing where it should be loose and where it should be tight.


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## kvom (Aug 25, 2012)

I use drill rod for engine rods, pins, etc., without doing any hardening.  It's not hardened when delivered, and in fact is relatively easy to machine.  Just order what you need from Enco.


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## kuhncw (Aug 25, 2012)

Here is a link specific to finish nails.  http://www.sizes.com/tools/nails_finish.htm

A 5D nail is 12 1/2 gage which is 0.099 inches  shank diameter.  Ref: http://www.sizes.com/tools/nails_wire_gauge.htm

Number 39 drill rod is 0.099 inches dia.  McMaster-Carr and others sell number size drill rod.  Even though it is called "Water Hardened", as others have said, the rod is not hardened when you buy it.

Regards,

Chuck


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## Brian Rupnow (Aug 25, 2012)

MarioM said:


> Checking an engine plan from Philip Duclos, it asks for a valve push rod made of CRS N. 5D x 1 3/4" finish nail.  Does anybody knows what it means??
> 
> Mario


 
crs is cold rolled steel. 5D is the diameter of the nail. Look at the bore in the valve guides to determine what 5d actually is.


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## Aydelott (Aug 25, 2012)

rkepler said:


> All of the drill rod I've bought has been fully annealed, about the only source of hardened drill rod would be a drill or reamer blanks and even then I'm not sure that it would be fully hard.
> 
> From experience if you make an engine to that sort of tolerance it will be very difficult to run.  If you're a little over in the rod size and a little under on the bore they just won't fit.  If the sizes are dead on and the bore is a little crooked same problem.  If a rod is a little bent (as metal is supplied) it'll jam at one end or the other.
> 
> A steam engine which is loose at most spots and tight at only a few will run like a watch.  Too loose everywhere and it'll run, but noisily.  Too tight all over and you'll have trouble turning it over with a wrench. The real art here is knowing where it should be loose and where it should be tight.


 well i was hopeing i could make it really close a lap everything in to a slip fit now im kinda freaking out i dont know what to do lol this is my first engine what kinda of gap should there be in the rods an the bore of the bottom cylinder cover?


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## Brian Rupnow (Aug 25, 2012)

A good sliding fit with no binding, but not sloppy either. If there is a gland on the engine you are using, the packing in the gland will tighten down on the rod enough to prevent undue air or steam leakage when you tighten the gland nuts a bit. Don't freak!! These small engines are very foregiving.---Brian


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## rkepler (Aug 27, 2012)

Aydelott said:


> well i was hopeing i could make it really close a lap everything in to a slip fit now im kinda freaking out i dont know what to do lol this is my first engine what kinda of gap should there be in the rods an the bore of the bottom cylinder cover?



Lapping really only averages a couple of surfaces together unless you embed the lapping compound into one and use it to lap the other which I don't think you were talking about.  It won't work when the 2 are too tight to go together or so far apart that they don't contact.  There are some cases when lapping 2 surfaces works well - when you have a shaft through a split bearing - in this case you can start loose and tighten up the bearing while lapping is taking off the high points.  In those case you need to use something like Timesaver's lapping compound as it preferentially removes material from the softer or harder surface in the process so that you don't wear down a crankshaft while lapping in the bearing surfaces.

I'd shoot for .001" fit on rod & pins, that's enough that oil will wick in but not so much that you hear a clank or click when it reverses.  Be careful with less than that in dissimilar materials and heat - differential expansion can lock something like that right up.  Same issue with similar materials in an area where you might lose lubrication and similar metals can and will gall against one another.

On a gland I'd shoot for good clearance - .002 is a start, I usually end up with .005 with an o-ring seal and try for less with packing as it can blow though.  I'm one of those guys who doesn't have luck with packing, I usually go to the o-ring solution right away.  But note that everything has to be in line - if the piston rod is off center the hole in the bottom for the rod would have to be off the same amount in the same direction, or you have to open up the hole in the cover to accommodate it.  So start a few thou over nominal then open it out to accommodate the error stack.  I always figure that if I made one I can always make another, and it's that thought that usually keeps me from throwing the errant part across the room.

So: take a little care in the parts you make.  If something isn't a press or interference fit make it a little over and make the parts that go though on-size and you'll likely have something that works when you put it together.  But taking too much care means that you're likely thrashing instead of working. 

But don't freak out at making a mistake - if you're not making mistakes the odds are that you're not making anything.  And most learning comes after making a mistake and not after doing something right.


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