[NOODL3]

Ok well first off i appologise for possible not putting this in the correct section but you guys have so many its hard to choice especialy with such a broad category of a qeustion.

QEUSTION/PROJECT: Ok i am just wondering what method i should use for my project...what i am trying to do i produce my own single axle( one whole axle all the way through the truck) "tech deck trucks"(small 96mm long skateboards, if you didnt know)...

i know and have partialy researched casting (sand,gravity, pressure etc) and all but becuase of the extremely small size of these trucks i am wondering the best method for production (possibly milling or other??).. thank you, your help is very appretiated... and if you dont know what a skateboard truck looks like heres a referance image
(life size skateboard truck):

the only parts i will need to produce would be the hanger(main top part) and the base plate(main bottom peice) none of the nuts, washers or bushings are needed...i would need to know how to thread the axles though.

PS: the "truck" is a two peice device(hanger, base plate) so they would most likely be casted/produced seperatly..

I am very new to metal work/machining so go easy on my please...i would like to learn and this project is very important to me. Please just tell me the best possible way to produce my product.

Thanks, NOODL3

EDIT: i couldnt put pics in my topic so if you need refrance pics check the attached files

[handlewanker]

Hi nood, to put it bluntly, you'll be swimming with sharks.
Are you contemplating manufacturing these to sell for profit?
Or do you just want to make a set for your own use?
As I understand it these are a new concept and will be copying the full size design, but on a smaller scale.
Depending on the volume required will determine the method of production.
For a few, make a plastic or wood pattern and get them investment (lost wax) cast.
The shaft diameter would probably be made to suit bearings and wheels available, and would be threaded using a lathe for a few or hand stocks and dies.
The shaft, of high tensile steel, could be pressed into the alluminium body with a light press fit or made a slide in fit and locked with Nyloc nuts on either side of the wheels.
This is a relatively easy job to tool up and make if you indicate the volume you intend to make, and what machinery you have at your disposal.
Ian.

[ViperTX]

You can cast the trucks in aluminum using sand casting, lost foam casting, or the lost wax process. Tumble them then machine the mounting surfaces and drill the mounting holes.

For the axles you might want to look at drill rod....it can be hardened if you think you need it. I would use a die to cut the threads for small quantities.

[NOODL3]

@ handlewanker-First off i would like to know what yeah mean about swimming with sharks, cuase if your talking about possible copy right problems i dont think there would be a problem since i will be a different design and all but if that was the concern please elaborate.

"As I understand it these are a new concept and will be copying the full size design, but on a smaller scale"-well i didnt quite understand this fully but thats ok, i think what you were saying was something about producing the same design of real life size skate trucks but in a smaller version, well i geuss this is true but the one i will be making the mold out of are the tech deck ones(trucks in first attached picture, which are pretty small and are smaller than and inch all around-main consern-will the small size be a problem?)

Yes i am thinking of producing these and selling them for profit on a relativly small quantiy scale, but if the process would be easier to do with either a smaller product quantiy or a bigger more "massly" produced product let me know cuase i am open to either way of production, i am just looking for the best. Also i would need a mold that i would be able to reuse or something that is cost effeiciant for use.

@viperTX-Main qeustion- will the size be a problem in any of these method, or better yet which would be the best and would work with good results with small peices being cast(look at attached file/pics for better size comparison)

"Tumble them then machine the mounting surfaces and drill the mounting holes."- just wondering what would tumbling do and how would i do it(any machine) also what do you mean by machine the mounting surfaces?

"For the axles you might want to look at drill rod....it can be hardened if you think you need it."- Using this method would i add the axles after the casting or during the casting

machines available- basic lathe(cuts alummunim but nothing higher in grade to my knowledge)
Drill press
and other basic and other no basic tools that i dont know but all have relation to A/C work(i have a freind who is a A/C repair guy)

[ViperTX]

Sand casting would be the way to go.......Tumbling only cleans up the surface...so you don't have to manually clean it up....adding the axles is a post-casting operation.

Machine the mounting surfaces....means....that the surface of the casting may be somewhat bumpy.....so you would want to flatten or machine that surface that presses against the skateboard.

[NOODL3]

ok thanks alot man i will research sand casting, and how/what machine would i use for tumbling(a tumbler? haha?)
also how would i go about adding the axles after casting because after making a mold of the tech deck trucks there would already be space where the axle would go...and also would i have to drill through the cast and then some how afix them inside(how would i do this)....ok thanks alot guys and you will probably be hearing from me more in the near future...if you guys could possibly post some links about some off the processes i will be going through during this production that would be helpful.....thanks agian for your help this is truly a great community and pardon and misspeels or total chaos in my post right now cuase im not reallly feeling to good right now....later

[merl]

noodl3,
Am I to understand that the size of the skateboard you are working with here is the toy size (96mm) one that is pictured in reply #4?
I'll assume for a bit that it is.
If you want to make the truck assembly for a few of these boards it could be done fairly easily on a small cnc mill. There are thousands of people on this site alone that could help you with this project. Try rewording your details so that it's easier for us to picture what you want (probably only you and somone who knows skatboards will know what a 96mm tech deck is)
All machineist work from a print or drawing of some sort. It's the best way for you to comunicate to the machinist what you want done. That's not to say that you need to make a blue print befor anyone will talk to you but, it would make things go much smoother.
Try re-posting this thread to the r.f.q. area and you might also get more of an idea what it would take and how much it would cost to make this part.

merl

[dertsap]

if you plan on small production runs the problem you may run into is the profit margin ,mainly because of , setup time , then you have to look at machine time , tooling ,tumbbling polishing ,coating , castings will be a few bucks a piece ,as long as you can keep your head above water for the first couple of runs ,you may be well on your way , once your product is getting to be known

4axis machining would be optimal , single operation

[handlewanker]

Hi Nood, the phrase "swimming with sharks" is a way of saying that you will be competing, at a great disadvantage, against someone who has the expertise and complete tooling and knowledge to produce these items and make a profit.
Even if you could get away with using an existing item as a pattern for casting from, and the person who makes them didn't find out you were selling their design for your profit, then you would have to make these items cheaper than the originals in order to sell them.
O.K. so we're going to make a few items and sell them on the quiet so to say, and have a bit of fun in doing it and also learn the field of product manufacture.
No problem, I don't think anyone is going to take out a court order to skin your hide for a few parts, that at this stage of the discussion would probably not resemble too much the item you're copying from anyway.
The first hurdle would start with the casting.
Alluminium is a very easy metal to melt and it can be done using a couple of fire bricks as a furnace and a ladle to melt the ally in and a propane gas torch to do the melting.
This is a very dangerous procedure and can be life threatening. A bit of expert supervision would pay dividends here.
The next hurdle would be the actual mold.
Bronze was being melted and cast several thousand years ago by people with no mechanical knowledge and no easy ready supply of the raw material.
The method used then was to form a mold in soft clay, having two halves, so that the part can be removed and the mould used again.
Some molds were just carved into soft sandstone and the metal poured in.
A mold formed like this, with clay, is then baked to drive out the moisture, and harden it.
The next method, commonly called the LOST WAX PROCESS, would be to form the part to be cast in wax, candle wax, and then wrap the soft molding clay around the wax part, pressing it closely to it, and leaving a hole in the top to pour the metal in.
The wax filled mold is now heated up slowly and the wax poured out to be reused.
The mold is heated further untill all of the wax is burnt out and the clay is rock hard.
The mold is then buried in a sand box with the open top sticking out.
Next the ally is poured into the mold.
It is at this stage that strange things will happen.
As the ally cools it contracts and the top of the metal starts to collapse down into the mold leaving a hole in the mddle.
To overcome this problem the mold has an extension added to it, when the clay is wrapped round the wax, to form a tube sticking about 2 inches above the mold and having a hole of 1 inch diameter in the middle of it.
As the ally contracts the metal in the extended part will collapse and so feed metal to the part.
If enough metal has been allowed for, then when the lot has cooled the clay is cracked off to leave the cast part with a lump of metal above it, which is cut off and remelted for the next time.
To speed up matters a number of molds are made with wax patterns in them and enough ally melted to to fill them.
This is just a thumb nail sketch of the first step in manufacture, which would be at the very bottom of the ladder of technology, but will still make a viable casting that would to all intents and purposes equal a regular commercially produce item, just takes a bit longer.
Be warned, this is a very dangerous occupation, having no experiance in safety methods or hazards allied to the casting industry.
We could write an essay on the machining methods that you could apply, using the very basic of tooling that would cost little to get or make.
If you want to have some more info' I'll go further, otherwise you can probably work thing out for yourself using whatever methods at your disposal.
Ian.

[ViperTX]

http://www.backyardmetalcasting.com/links.html

http://www.efunda.com/processes/meta...ting_intro.cfm

You should search this site...this is the 2 time I've posted these links in the last couple of weeks.

[jeffs555]

To throw another wet blanket on the fire, have you even considered the possible liability problems? In todays litigious society, producing something like this without complete engineering analysis of the structure and materials would be dangerous to your financial future.

[NOODL3]

After thinking about this last night i would assume to produce 20 PAIRS of trucks for starters.- just so you know a more approximate number on what i would like to produce.

EDIT: After readign some resources, it has said that sand casting is for large parts, is this true?

@ merl- first thanks for your help, now in regards to your assumtion about the "toy"(96mm) skateboard, yes you were indeed correct about your assumtion. Also thank you for your sugestion about possible making a drawing to give you guys a better idea of what im talking about, i will be working on that currently on some computer aided program possibly...or maybe for even a more rougher draft, microsoft paint. I will not however be able to make a drawn sketch since i have no access to a scanner.

Also on a small scale like you said, would a small cnc mill be able to produce identical peices?

@ handlewanker- thank you for you explanation of your phrase and for you enlightenment on copy rights and such....but just to make things clear i will be selling these to a specific relativly small "scene"(or a big group of friends) and not to the genral public in stores and such...or at least not yet. I will also after getting the basics down and understanding the manufacturing process of my first batch or so(proto types), make changes in the actualy design of the truck even more (the design is already altered at the start becuase of the single axle rather than the 2 pin method they use)to make it know that there would be know copy right problems and that it is a totaly different product. Also thank you for a more indepth study on the casting process and all your insights. Someone that i have talked to personaly has said that it might be better to use the lost wax process in this situation becuase of the small scale and detail, what do you think?

@ jeffs555- i realy didnt get what you were trying to say i mean are you saying that there might be liabilty problems cause you think someone might get hurt riding one of my products cause if so i would like to let you know that that is very doubtfull since the trucks that i will be trying to produce are fro finger sized skateboards ones that cant be ridden, only by fingers...if this is not what you meant i am sorry for my assumtion and please elaborate what you were trying to communicate, thanks.

i would like to thank everyone agian for all there help and i hope this project will all work out.-NOODL3

[merl]

noodl3, don't get me wrong, I wasn't saying that your progect is a toy, only that it is that size. In other words not somthing that you could ride on your self.
I could see by some of the other posts that most of us thought this was something full size as you were showing in your fist post. Once I relized the actual size of the thing then that changes the way I would approach makeing it.
In this case I would suggest that you take another picture of the board with a ruler or a machinist pocket scale in front of it so everybody can get a clear idea of the actuale size right away. This will help us to help you figure out how you would like to have the parts made.
The answer to your other question is certainly yes if you can find somone with a "desk top " size cnc mill who has a good CAD/CAM settup they might be willing to do this part for you.
Agian, the quickest way to get the responses you're looking for would be to post this as an r.f.q. on the employment forum.
The parts on the board you have were probably made by die casting. That is a casting process were the molten aluminum or zinc alloy is forced into a set of dies under high pressure. The dies are kept at a certain temp. so that the metal will cool in just a few seconds and then the die cast machine opens up and ejects the part then closes and starts the cycle over again. This usually happens in a short amount of time depending on the size of the part and its complexity.
One of the machines I used to run would probably spit your truck parts out in about 1 second each. I'm sure that sounds cool but, you must also relize that to make the die for that machine would cost around $20,000 or more and you would need to order at least 10,000 parts per month every year just to get on the schedual.
There is more than one way to skin a cat. There is also the spin casting process but again the cost of developing the die is still more than the part is worth unless you go into mass prodution.
I think you could carve these parts out of a solid chunk of aluminum fairly easy on one of the small table top machines I mentioned.For the quantity your talking about you could even do it on a manual mill if you had good eye/hand coordination.
Keep thinking!

merl

[handlewanker]

Hi Nood, the lost wax process will give you repeatable "castings at home" on a small scale as you don't have a time/employee cost structure to worry about.
You will have to get some silicon rubber compound to produce the wax blanks.
First you make a master part using plastic, wood, moulding clay or any material that carves easily.
Then you dip it in silicon rubber a couple of times to form a mold.
When the silicon rubber has cured, it can be peeled off of the master to leave a cavity that you pour the melted wax into.
This will give you a continuous supply of wax impressions, all the same.
Now the next step is to form the mold to receive the molten alluminium.
The wax impression is examined to make sure that the silicon rubber mold produced a workable impression.
If all is well then the wax impression is dipped in a ceramic slurry that coats it. Several "dip ins" are required to give a shell round the wax.
To make handling the wax impression easier a 1/4" round wooden dowel is put into the silicon rubber mold, and left sticking out about 1", while pouring the wax in. This will give you a means to handle the wax impression without it going soft on you.
The ceramic slurry is used in preferance to clay as it will enable you to work easier.
It is in a thick cream like consistency and can be obtained at craft supplies or wherever there are ceramic crafting done.
If all else fails then the clay can be mixed with a bit of water to thin it down and used for coating, though this is more fragile and doesn't take to baking hard very well. Plaster of Paris could also be tried.
Whatever material is used it very important to bake it to melt out the wax and dry the mold thoroughly, otherwise it will EXPLODE on you as the molten metal is poured in and you'll be wearing it, quite a dangerous process.
Once the wax impressions are coated they are stood upright to dry, and the wood dowel can now be stuck into a piece of wood with a series of holes drilled in it to form a rack.
Once the coating has dried it can be gently heated to melt out the wax, (very fragile at this stage), and then further baked to remove all traces of the wax and harden the shell.
It must be remembered that the molten metal WILL contract, so the extension at the top pouring hole is to allow extra metal to offset this.
Last but not least, as soon as the metal has been poured and has gone from the liquid state to a hard state, but while still very hot, the mold is dropped into a bucket of water. STAND WELL CLEAR!
The ceramic or clay shell will shatter on contact with the cold water and leave you with a clean casting, otherwise if it cools on the casting it is the very devil to crack off.
At this stage you will either be licking your wounds or admiring a shiny clean casting. Some parental supervision is strongly recommended.
If you reach this stage without too much drama then you will probably be wanting to either, expand your production as your mates all clamour for your products, or find a better way to do it.
If you stay with the casting as a "do it yourself" project, then a simple electric furnace could be constructed very cheaply and so simplify melting the ally, but now you will be flying with eagles, whereas you still have to get off the ground.
A totally different method would be to get someone to produce two mould halves out of steel using a CNC mill etc and go down this path. Choice is yours.
The steel mold process is complicated and more costly, if you have to pay to get it machined, and will only make one part at a time, whereas lost wax is DIY and can produce a dozen or more with one melt.
By the way, the axle is made last and is a simple slide in fit in the casting.
As the trucks will not be bearing a persons body weight, then the wheels could be held on by a screw, from each side, directly into the casting which is tapped to hold it.
The screws, which are Allen headed cap screws, will now become the axle(s).
Ian.

[jeffs555]

NOODL3,
I didn't notice the very small size of these and was thinking of something you could ride.

Is there a really active enthusiast market for these? How much do you think they could sell for? I see complete 96mm boards with trucks selling for less than $10, most probably made in the far east. Could you really charge enough for the better quality trucks to make it worthwhile?

Jeff

[NOODL3]

I will respond to merl and handle in a little bit as i research some more things and have some time to right a reply but...

@ everyone that is helping me(merl, handle...etc)- please read the orange text below becuase this is also a major factor in this project, thanks



@ jeff555-that cool that you didnt know about the size....but in regards to your question:

I admire your research and you exactly correct, but that is just for "tech deck" or massly produced boards. There is actualy a moderatly sized "fingerboard" scene in which uses mulit-plyed wooden boards instead of cheap non-responsive plastic ones(tech deck etc) and use urethane lathed wheels with alumunum cores and bearing inserts compared to the sticky/crappy fake like feelling ones you get in massivly produced(plastic) fingerboards. This "scene" was primarly started and popular in germany at first but has now branched all over the world including the US. Well lets just say this, good quality wooden fingerboard companies(just the deck(board)) sell their decks for an average of 30 USD, and so far no one has created any aftermarket trucks so I dont know really its still kinda up in the air but i could easily get $20- maybe 30. Its all depends though....why how much should i need to sell these for in order to make a profit/how much will the manufacturing process cost(estamate)?

[NOODL3]

EDIT: Attached files/pics in refrance to what i am talking about

@ handle wanker- ok thanks for everything, realy...your exlanation on the lost wax process was helpfull and everything else aswell...the only thing i had question with was this comment

"By the way, the axle is made last and is a simple slide in fit in the casting.
As the trucks will not be bearing a persons body weight, then the wheels could be held on by a screw, from each side, directly into the casting which is tapped to hold it.
The screws, which are Allen headed cap screws, will now become the axle(s)."

From what i gathered from this is for your design you would just (after casting) tap the holes and put in two screws(one on either end) thats great and all and i appreiciate it none the less but what i am trying to do is make single axle trucks(like real/full sized ones), although a person wouldnt be standing on it...the force exerted while fingerboarding sometimes is quite harsh actualy....and i probably wouldnt even have an issue with this method except this is how tech deck make their trucks and from experience the screws fall out/bend and are not sutible for fingerboarding, thus why im out on this adventure in the first place(haha) so i hope i didnt misinterpret your comment but could you please explain how i might embed the single axle into the casting now that i have hopefully made it more clearer...sorry for that

[ViperTX]

The premise was that the axle was a single piece axle....you would add it to the casting after the casting was finished....the clamp screw would hold it in place and the wheels could assist in keeping it centered.

Go to buildyouridea.com and look at the guys lost foam casting as an option to the sand casting.....I still think sand casting is #1, lost foam is #2 and lost wax is #3 for this part.

[keebler303]

you could tap the trucks for larger screws and therefore prevent the bending and falling out. You could look into shoulder bolts which you could tighten down and would probably suite this use well if the proper size could be found.

Matt

[handlewanker]

Hi Nood, I've sketched a wheel set-up, for one wheel, as I see it for ease of production and simplicity and am attaching it.
It consists of an alluminium or steel insert that is bored through to accept two ball races.
One spacer is pressed into the insert to form two shoulders for the bearings to fit up against.
The urethane is held onto the insert by being pressed on or glued.
The axle is threaded on the ends to accept two nyloc nuts and is a slide fit in the truck.
On assembly the spacer on the spindle holds the two bearings apart when the nuts are tightened to hold the wheels to the trucks.
I've colour coded the sketch as it only confuses to add a whole lot of arrows and name tags.
If you want the sketch bigger I'll redraw it.
Ian