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I Forge Iron

Making an all steel wheel


rockstar.esq

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I'd like to make wheels for my forge to make it easier to set up and put away (I forge outside).  The wheels would need to be fairly large diameter to deal with uneven ground so I'm thinking 18" diameter or thereabouts.  I'd like to make the wheel/tire, spokes, and hub out of steel.  I've bent an awful lot of conduit, but I've never bent a piece of flat bar into a perfect circle.  I'm planning to make an adjustable bending fork for my vice, as well as a pair of forks to bend with.

I was thinking I'd use a short section of pipe for the hub that would accept standard sealed bearings. My plan was to drill the hub to receive tenon ends on the spokes.  I was planning to either drill or punch the tire to receive a matching tenon on the other end of the spoke.  From there, I was planning to forge half the thickness of the tire at each end of the tire such that they overlap without any additional thickness.  I was thinking I would rivet the spokes to the tire.  The tire overlap would occur at a spoke thereby allowing me to get everything worked into place cold before I stick it into the forge to heat the tennons for riveting.  I don't have an oxy acetylene torch.

Since the hub end of the spokes would be secured entirely by tire tension, this whole thing will want to fall apart until the overlap rivet is tight.

I don't know if I can expect enough flexibility in the works to allow me to use a ratchet strap to pull the tire overlap into place, or if I should make a slot on one end of my overlap to let me snag the spoke, then draw it tight with clamps.

I'm thinking 1-1/4" wide by 1/4" thick stock for the tire, 1/2" square for the spokes, 3/8" for the tenons, and 1-1/4" diameter pipe for the hub.

I've seen how steel tires were fitted to wooden wheels by heating them up to expand the diameter.  I don't know if I can expect sufficient expansion to allow me to get the tenons slipped into place.  I sure would appreciate some insights from folks who've done this kind of thing before.

Thanks in advance.

 

 

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I'd suggest looking at how old agricultural steel wheels were put together; actually 18" is not too far from old steel wheelbarrow wheels; I've picked up a half dozen at the scrapyard at 20 cents a pound and use them for tong racks.  1/2" sq sound very large for a forge!

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I'd definitely recommend looking through eBay and searchtempest.com to see what antique wheels are in your area.  You can usually find some really nice all-iron wheels for pretty cheap.

if you're dead set on making your own, the hardest part is tying the hub to the rim.  Start with the type of bearings and build out from there.

 

You can definitely do it all on your own.  Folks have been forging wheels for quite a few eons, so you shouldn't have too much issue unless you try reinventing the wheel.  To roll over bumps and brambles, you need a wheel that's at lest 10" in diameter.   You can go larger, but going smaller is just asking for trouble.

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Thomas,

I've actually been doing a bit of looking for examples to mimic online, but I haven't stumbled on the right keywords.  For the most part I'm getting automotive wheels with the odd wooden carriage wheel.  I'm curious what their order of operations would be.

 

Vaughn,

I'm sure you're right about iron wheels in my area.  There are some antique stores I could visit on the weekend that might have something to look at.  I'm interested in developing my bending, tennoning, and riveting skills.  You're absolutely correct about the wheel diameter.  I had some 10" pneumatic wheels on my last forge and they were barely adequate.  I'm tired of the flat tires, and it's a neat opportunity to have some panache on my forge.

Thinking about this some more, I was considering making curved spokes like some of the steam- era flywheels have.

spokes5.gif

  If I had round tenons, I could assemble the wheel with the hub outside the tire, then press the hub into the center of the tire.

I was thinking that if I chiseled radial grooves on each tire mortise (staking) on the outer edge, the riveted spoke tenons would lock in place, keeping the hub aligned with the tire.

The advantage there (I think) is that I could weld the tire before assembling the wheel.  That way both ends of the spokes are captured during final assembly.  Since I'm working with a forge and not a torch, it would be much easier to move in and out of the fire for each rivet, if the tire wasn't trying to pop off constantly.  I could potentially clamp two opposing spokes with pipe clamps to keep the hub in plane with the tire on one axis while riveting the other.

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Rockstar, I love old flywheels and stuff but I don't recall ever seeing curved spokes like that on anything that takes any weight. If the forge is light enough it may work, but my guess is the curved spokes could bend over time if sitting on one spot putting the wheel out of balance.  Tho I think it would look really cool. 

I don't have a lot to offer here but I have a wheelbarrow at home with a metal wheel that I could get pictures of when I get home. I also have some old heavy wagon wheels. Don't know if it would help with process. 

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Rather than trying to scarf the lap joint to avoid a lump just cut the strap to form a butt joint when rolled to the desired diameter then just lap the ends enough for the weld and forge it back to the desired dimensions. forging it down will lengthen the rim to the correct diameter.

Rather than using bending forks I've had good luck using a piece of pipe for a die and hot bending the stock around it. for a one off plywood works fine. If you weld like I describe above bent the rim till it overlaps enough, mark and cut it with a hack saw. It's an unnecessary hassle measuring and cutting the strap first it makes it a LOT harder to bend.

Once it's welded and the hump drawn out let it cool, measure the diameter and warm it up to 450f and measure the diameter again, you only need about 5/16" across the diameter to fit the spokes it should be good for that at 450. If not get it hotter in increments. If you have to heat it to near red heat, say above 900f the tire will stretch and it'll be loose.

Another idea that makes fitting the spokes a lot easier is to give the spokes that swoopy, flattened S bend like you see in old machinery everywhere. The treadle pully wheel on my Grandmother's Singer treadle sewing machine is a perfect example.  I've never bent a spoke but I've thought about it often. The jig I came up with but never tried, is a center with a slot to fit the center of the spoke then two pins to receive the tire end. Heat the stock between the pin and hub and turn the hub say 1/8 turn and straighten the pin to align through the center. Two pins on the tire side because the spoke will be longer than the radius of the wheel so it'll need to be able to draw some extra stock as it bends.

This kind of spoke would need to be solidly attached or it might spring out on a hard bump and being mild steel instead of cast iron the wheels will have some spring to them. A person could use flat bar, say 3/8" x 3/4" and bend it the hard way to stiffen it up. It could be forged to give it a swoopy profile to go with the "S" bend too.

Just so you know, Other than welding and forging the lap joint on the tire I'm speculating here. I've done the lap weld and it works as advertised in Art of Blacksmithing and a couple other books. the thing about the spokes is just things I've thought of for I don't know how long, years.

I agree, buying wheels would be a LOT easier and probably faster but if we wanted to just buy stuff we wouldn't be blacksmiths would we. ;)

Frosty The Lucky,

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Kubiack, thanks for that resource.

Charles, I looked up the UN book, it's free on google books.  Thank you for telling me about it.

Thomas,  I tried all kinds of variations but hadn't considered "implement" wheels.  That nailed it!  Once you know the right term, all the answers are easier to find!

Daswulf,  I wondered about that too.  My forge is a bit portly as it's a side blast with a sand filled box.  I don't know what to expect.  It seems like the tire would put the top spokes under tension when the bottom spokes were under compression.  Of course if the spokes are springy, it's all a bit dicey.

Frosty,  I think I understand your idea regarding the swoopy spokes, however I'm not too sure about the 5/16" across the diameter being enough.  Most of the implement wheels I'm seeing have a fairly significant rivet on every spoke.  Just spitballing here, but I'd imagine I'd need somewhere in the vicinity of 1" to 1-1/2" larger than final circumference to get the tenons into the tire holes.

Looking at the images of implement wheels, I'm seeing a trend towards a pair of rings on either side of the hub with spokes alternating from side to side.  Many of them look like they're cast iron at the hub end, but the spokes are clearly riveted at the tire.  I'm not sure how they put all that together because the rivet heads are large enough that they must have had a decent amount of tenon poking through the tire to start with.  It occurs to me that maybe they riveted the spokes to the tire first, then they inserted the spokes into the hub while it was pulled out of plane with the tire.  I'd love to see these being assembled.  My bet is that it would look easier than it really was.

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Ooooh I LOVE brainstorming. Spitballing is fun too if Mom doesn't catch us.

I did a search of "Engineeringtoolbox.com" for a simple chart. Silly engineers kept throwing formulae at me so I persisted and for something that approximates a number I think a blacksmith can work with. With a starting of: 0F and a final temp of 400f. 100' of carbon steel pipe will expand 4.6'. That lets ME approximate a 432F temp increase causing a linear expansion of 4.6%

That'd be about 2.3" on a 56.5" strap yielding an increase of about .73" dia. If I were any good at math I could tell you what a 500-550F increase expanded the tire but I think THAT'S spitball close. Hmmm? You don't need to slip all the tenons in at the same time, one spoke one end at a time and work your way around the tire. I threw out the 5/16" tenon length as a guess based on 1.5x the dia of the hole rule of thumb for rivets or piened tenons. I think a realistic tenon on 1/2" sq would be around 3/8" dia, max making the tenon what 7/8"? Close but I think within range.

This is the link if you do math. http://www.engineeringtoolbox.com/thermal-expansion-pipes-d_931.html

Frosty The Lucky,

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The original post proposes a fairly elaborate solution, to what is otherwise, a simple problem.

Which is fine, ... if you want to do it that way. "just because".


But using a bending fork to form an 18"+ diameter circle, introduces truly unnecessary levels of complexity.

 

Traditionally, "tire" rollers were among the first simple machines adopted by Wheelwright's, ... and there's an obvious reason for that.

Such machines are still very common.

But lacking that, the diameter you need can be easily rolled on just about any kind of ring roller or slip roll.

( YouTube has videos of how to make your own simple ring roller. )

 

If it were me, I'd start with a double length of strap, and roll it into a continuous coil of the desired diameter.

Then I'd make one saw cut across all the overlapping ends, ... Resulting in two rings, ready to be butt welded.

( Wrapping a steel strap around a circular form, can yield an acceptable result, but inconsistencies in the material, or in its temperature, will tend to yield an irregular shape. )

 

Next, ... If curving spokes were a good idea, you would see them on motorcycle wheels.

You don't, ... Because they make centering the hub unnecessarily difficult, while contributing nothing to the wheels utility.

Again, ... If you want to make the project difficult, for whatever reasons, that's a different issue, and you should do whatever makes you happy.

 

 

I really do "get it", ... and often waste unconscionable amounts of time on simple little things, ... just because "that's the way I wanted to do it".

Either way, ... Enjoy.   :)

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Frosty,

Thanks for the explanation,  I misunderstood what you were saying about the expansion.  Knowing that the tire expands that much lends some confidence to the idea that the hub and spokes are assembled first, then the expanded tire is set over the tenons.

Daswulf,

Thank you for all those photos.  It's interesting to me how the simpler wheel has a pair of plates clamping the spokes at the hub side, yet the more complicated wheel has two rings that appear to be either tennoned or welded. The simpler wheel looks like it wouldn't require heating the tire to get the spokes assembled.  The more complicated wheel looks like it'd be a real wrestling match to get everything aligned with the hot tire.

Smoothbore,

I appreciate your candor.  Looking back, I think the appeal of the bending forks is that I don't have any, and this project would be an excuse to make them.  Now I'd have to admit, I don't have a ring roller either so the same excuse applies!  That being said, I can see how a wonky tire would potentially make the whole assembly more difficult, and the final product less satisfactory.  Rolling makes a lot of sense, especially when you consider the appeal of having both tires side by side for comparison before cutting the joint.  I hear you on the curved spokes too.

Just out of curiosity I called a local fabrication shop and asked them to quote rolling the tires.  $75 per each struck me as a bit strong.  These guy's are selling an entire wooden wagon wheel for less!

 

 

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 I find myself agreeing with Smooth Bore on most of his points. Making swoopy spokes wouldn't be an issue with a portable forge, it's not like you're packing 300lbs in a single wheel barrow or going fast. Or DO you go fast pushing a wheel barrow or hand truck? 

A set of rolls would be a good thing but I don't have rolls so I just heat and bend around a mandrel. Truing up a circle isn't that difficult and certainly a LOT easier than using forks!

The two part hub Das posted really sings out to me as easy greasy. Rectangular bar, mortise and piened tenon at the tire and punched and riveted to the hub plate. making one of those sounds like a job for the clean up & gofer shop boy. Once a person had a couple jigs set up you could turn out matched spokes really fast. I'm thinking maybe a dozen an hour before you built a rhythm.

Mortise an end on a bar. Insert it into the 9"r arced monkey tool on the jig, set the shoulders and cut the tenon to length with the built in shear. Heat the other end insert the tenon back in the monkey tool end, punch the rivet holes in the hub end and shear to length done deal. It'd take a couple hours of careful measuring to fab up the jig and the punches and shears but. Once the tool was made making spokes would go fast, Fast, FAST. Probably just do it all in one heat once you got the COE numbers. What 5 whacks with a sledge hammer? Lets see, 2 to shoulder, 1 to cut tenon to length, one to punch rivet holes and one to shear to length. Ah, the slowest operation would be forging the tenon in the first place, say 30 seconds under a power hammer a minute or so by hand?

I'm thinking making the hub is the is the slow finicky part. Drill press, 4" hole saw and a "hub bearing carrier size" hole saw, plate OD and bearing hole centered and done. 10 ga would be overkill but not outrageous, 12 ga. would be fine I think. Laying out and drilling the rivet holes in the hub plate would take time, I'd do it before hitting it with the hole saw for the bearing carrier. One center punch mark to lay everything out.

I'd go with a single plate hub, a double plate would take a lot of finishing to swage it down around the spokes or it'd be a heck of a dirt trap. Way more than 2x the work and I'm basically a lazy guy. I grew up under the edict, "Work smart NOT hard." (smart as I can :))

Frosty The Lucky,

 

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If you'll notice, most farm implement wheels have a second feature--the actual tire is either concave or convex...or sometimes beaded to give strength to lesser material thickness.  This allows one to more easily form the tire from thin material and then get the stability of a MUCH thicker section.  Possibly the O.P might consider using thin material for the tire which would be easy to form into a ring--and then forge in a cup or crown for the strength which wouldn't be too bad to accomplish with a simple bottom die.

A cupped tire also keeps the heads of the spokes off the rolling surface of the tire so you don't have to hide the rivet ends (or even nuts) on the spokes where they engage the tire.

Spokes don't have to be complicated or heavy-weight.  It's the tire that needs the strength to keep the spokes in tension/compression around the whole of the wheel as a *system*.

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I was looking at some of the old spoked wheels for sports cars for a different take on the issue.  Though the wheelbarrow wheel Alan posted has an elegant simplicity to it...

Rather than work with heat shrinking the spokes in place I would probably give them a bend, fit them in place and straighten them on the anvil until they engaged and were ready for peening.

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16 hours ago, rockstar.esq said:

Just out of curiosity I called a local fabrication shop and asked them to quote rolling the tires.  $75 per each struck me as a bit strong.  These guy's are selling an entire wooden wagon wheel for less!

an entire wooden wheel for less that 75 bucks, Wow last I bought were 4 times that and those were 15 yrs. ago.  Going to a Fab. shop asking for 4 of something they don't usually make will cost more as they have set up time from their normal sizes and most likely time to reset up for what they do make.  In any shop Time is $ 

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Hey Rockstar thanks for all the great business insights. Payback is a beach.

Curved spokes: designed by patternmakers for cast wheels to solve casting problems, not about style at all, they are simply less likely to crack during the cooling ( shrinking) stage.

Cast iron spokes are always in compression,  never in tension (not the curved ones at any rate)

Since iron ( mild steel or wrought) is highly elastic (compared to cast iron)

compression spokes are NOT  a good idea.

My only other input, countersink the rim so the majority of the piened tennon is in the rim elsewise all your fine work will fall asunder when the piens wear off. 

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notownkid,  I understand your point and the shop certainly has a right to charge whatever they think it's worth.  I may have stumbled onto a shop that's either too big, or too busy for my little job.  That being said, their price communicates "go away".  They could have politely declined the job and referred me to a smaller shop. 

aftist, I'm glad you appreciate the insights, but I think you might have misunderstood what I was getting at.

I posted the prices to show how even if you didn't know the going rate for material and shop labor, you could still compare the value of what's available.  I can think of several reasons the shop's quote was high, some are OK, others not so much.  I'm more sympathetic to a shop that's struggling to pay it's workers a decent wage for example.  Even if that were their case, my little job wouldn't keep them in bread and butter for long.

At their rate for rolling four tires, I could buy a modest ring roller, make the tires, and sell the roller at a loss for less than they're asking.  That assumes there's a selling market for used ring rollers, and that I could afford to have the capitol tied up until they sold. 

I'm not sure I agree about the spokes under compression all the time.  Take a flywheel for example, a change in velocity is going to have the leading edge of the spokes under tension, with the trailing edge of the spokes under compression.  The curved spokes are going to have more surface area carrying the tension and compression than a straight spoke.  By spreading the load across more area, the tension (and compression) load per unit area is reduced.  As cast iron has little tension strength, the curved spokes on flywheels make a lot of sense. 

Axial loads would be a different story because the curved spokes would present a leaf spring that get compressed along the plane of the load, and stretched perpendicular to the load, allowing the tire to go oval to whatever degree the load exceeds the spoke's coefficient of spring.  That being said, cast iron's high compression strength probably reduces it's coefficient of spring. 

Come to think of it, I had a Yamaha Virago with a cast aluminum (or magnesium)  front wheel that had curved spokes.

Frosty, I like your thinking.  I tend to think in terms of multi-use tool making instead of a dedicated jig.

Thomas,  I like your idea about bending the spokes.  That's a very good idea.

Alan,  thanks for posting that image of the wheel, it's a practical answer for sure.

Big Gun, I'll have to look around some because I've mostly seen corrugated culvert pipe in 18" diameters.  It's a good idea and maybe I'll turn something up at a scrap yard.

Kozzy, Good point about the tire curvature.  I like that it gives me an excuse to make a bottom swage!

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Don't forget other sources than pipe, I have a scrapped propane tank that would make good sized wheels with appropriate safety precautions during the cutting! (It was a farm house tank and is 14' long and currently the biggest item in my scrap pile...I think it's going to end up going to my Pastor to build a smoker from; ok 2 smokers from...  My local craigs list has had several folks trying to sell implement wheels lately; but that would take the fun out of building them.

I did think of welding in a disk and then using a plasma cutter to cut it into spokes, (save time if you didn't weld the areas that will be cut out...)

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True I was thinking of a longer run than say what 16  to 24 spokes. Truth is I'd plug weld them to the tire and rivet to the hub plate. Leave a bead that you can dress with a rivet header while it's still HOT and nobody you don't tell would know the difference.

That Philadelphia blacksmith guy name of Miller invented the arc welder for a reason you know. ;)

Frosty The Lucky.

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