Thread: my first build
first off i guess i should say hello.
my name is Adrian and i am new here. recently i have found myself needing something like this and after some googling i found that it is doable.
this is going to be a tight budget build mainly because i was recently made redundant. i got some sound advice from a few guys here and what i realise is that i really needed to make some realistic decisions about what i want this machine to do. after some thought i feel that routing mdf or plywood is what i need, milling alloy would be nice but not a requirement.
the design will be a moving gantry with a workable area of roughly 2' by 4'. that is not set in stone and may be changed later as i work out the details.
the bulk of my budget will go on a controller/stepper package. i do have some electronics training but i wouldnt be confident in the reliability of anything i could build. since this is an important part of the machine i guess i should get this part right. i dont want to spend hours trying to get the machine working only to find the controller isnt working right. i am looking at a kit from http://www.diycnc.co.uk/html/cnc_systems.html
it is the three axis kit for £207 i am looking at.
if anyone has any feedback on these products, good or bad, i would be interested in hearing it.
the machine will be primarily constructed from mdf. i do have a table saw, router table, pillar drill and some other stuff so i shouldnt have much trouble making the chassis. i will keep an eye out for some second hand linear bearings and lead screws but for the moment the good stuff is out of my league so i will attempt to make my own. i will design the chassis with a view to maybe upgrade it if i get the chance.
my idea at the moment is to use threaded rod and make a delrin or nylon nut, use some ball bearings at either end and see how that works out. i understand that direct drive of a threaded rod will limit my feed rates but i am thinking i might try to gear it somehow, anyone any experience with this method? also i do understand that ball bearings will not handle the thrust loads and that is something i will look into.
on the linear end of things i am thinking of getting some nice straight angle stock, probably alu, and making a linear bearing like i have seen on some builds here. this idea basicly has some mdf chamfered on either end, angle fixed to the chamfered ends. on the gantry side it has some more angle with bearings fixed to it, one assembly fixed top and bottom of the rail. one problem i see with this design is possible loose or tight fit. i intend to make the bottom bearing on the gantry spring loaded with a bolt to adjust the tension. i can see it in my head but its a bit hard to put in words. i think it should work well, in theory at least.
i have gotten hold of solidworks and i am trying to model my ideas so i can see how the various parts go together. it is a steep learning curve though as i have only ever used CAD electronic design before, not mechanical.
anyway i guess thats it for now. i will continue to think through the design and try to model it, might post some pics of the model to get some feedbcak. it will be well into the new year before i put blade to wood because i want to have a clear plan.
i would like to thank all the guys for their advice so far and i hope to get some feedback on these ideas as i will probably keep second guessing myself.All work and no play makes Wires a dull boy:twisted:
You have done it now you know there is no turning back :clap:. A few pieces of advice i can give you is that sometimes it is better to swallow hard and buy the right thing if you can. When you look at the cheap stuff and it does not work you then look at the next bit of cheap stuff and you end up paying twice. With that you could have just bought the more expensive item in the first place. A good place to save money is the mounts. Why use them if you can tap out the ends of the rod and put a decent beefy screw in? this also helps in that you are drilling smaller holes and better for accuracy. remember that bearings need to go onto turned down rod ends and not directly over the thread (my mistake).
I used the Chinese 5 axis all in one drivers you see on Ebay. these have worked out for me but did take a lot of working out. In hind sight i should have gone for a modularised unit as i am limited to no more that 5 amps.
PS set a date to first cut as it is a good kick up the jacksy when it looms i just made mine by 1 weekIf the nagging gets really bad......Get a bigger shed:naughty:
the reason i am looking at this controller is that i have read that it is quite easy to blow a stepper driver, particularly when you dont know what you are doing. with this board that only means you need the driver board and not the whole thing as is the case with single board units.
power supply wont be a problem. like you said, will just keep an eye on the bay from now on for a deal.
with regards to the linear stuff i have come to the realisation that this will not be my last cnc machine. what seems to be the norm here is that you build your first machine and use that to build your second. i know my linear idea is tricky and will take some time to get right but i have lots of time now and i do have lots of patience to get it right. also i am pretty handy with the table saw and router. when i get it modeled i will post some pics for feedback.
i like that TR12x3. the price aint bad either, i might just go for that. it seems i will have to get the ends turned down to fit bearings and coupler. i will have to find someone local to get that done, might know a guy.
i had a good look around the dryline site but i cant decide which size rails and bearings i need. guess thats just my lack of mechanical training.
with reagards to 2e0poz points i do see the logic in buying the propper stuff and under normal circumstances (have a job) i would definatly just spend the £500 on linear bearings and be done with it but i really dont have the cash at the moment. that might change in the future but for now this idea of mine wont cost much to try. i already have mdf and i have a load of ball bearings which might do the job, all i need is some alu angle and a lot of time (being unemployed, time is not a problem). i am not sure i know what you mean about mounts, could you elaborate?
the reason for not doing any construction right now is there is no point in cutting a load of mdf only to find the design change and stuff going in the bin. in my mind its better to just get the design finalised and then as 2oepoz says, you get it made in less than a week.
i can see the advantages of propper linear bearings but i just cant afford them at the moment plus i am not convinced they would really make that much difference to my machine given i will just be cutting mdf or ply. assuming i can get my the home made linear tight engouh and pay close attention to minimising chassis flex i think it will work out fine.
like i said this is my first machine and it will have specific uses. no doubt i will make another more elaborate one soon after this is completed and if i have a job at that time i will put all the propper stuff into it.
thanks for all the advice guys even if i dont take all of it, its just a budget thing. i am getting pretty excited about all this, keep having ideas flying around my head. cant imagine what i will be like the day i fire her upAll work and no play makes Wires a dull boy:twisted:
You might find the use of a grinder to take the hardening off the surface helps, a dremel or similar is an alternative to a file and can be quicker...
At least one member has used this technique successfully...
Of course if you know a man with a lathe...
i have been trying to think how i could do that myself, that sounds simple enough. i have a bench grinder and vernier calipers.
i do know a friend of a friend who works in a tool making workshop, might see if i can call in a favour when the time comes.
being a noob i am not sure what a pillow block is. do you mean a small square of mdf with a hole for the bearing? you then make a hole larger than needed in the machine chassis so that the pillow block can be moved to line it up perfectly?
also, if i am going to get some thrust bearings i need to understand them a little. my understanding of thrust bearings is that they handle the load laterally along the length of the screw but they have no ability to handle side to side loads. do i need a ball bearing and a thrust bearing in each pillow block or am i missing something?All work and no play makes Wires a dull boy:twisted:
ah i see. so if it is supported by thrust bearings either side of a ball bearing on the drive side of the screw there is no need for a thrust bearing on the other end, just another ball bearing. i think if i am going to go that complex on the machining of the ends of the screw i will just get someone with a lathe to do it right.
thanks for clearing that up for me, i was wondering how exactly i would do that. one more thing decidedAll work and no play makes Wires a dull boy:twisted:
if you look at my build , i turned down 12x3 trapeziod screw
with a drill , grinder and file it turned out really well
i have the system 3+ board from diync also a power supply
support from roy is first class
i built my router from mdf to start with but i am now in the process of rebuilding in aluminium , should have went the alu route to start with
Sorry I totally missed the point of the cash flow issue and i can appreciate your position. I did explore the use of patio door rollers as slides. I buttered up a couple of window fitters to have a butchers at some old patio doors and i was pleasantly surprised at what i still believe to be a viable idea for a low budget machine? just a thought or you could just go for plain old Bronze bushes?
PaulIf the nagging gets really bad......Get a bigger shed:naughty:
BUILD LOG: New Build - For Your Amusement - MK-2 buildBy Karl in forum DIY Router Build LogsReplies: 11Last Post: 11-06-2012, 07:34 PM