Thread: new build opinions required
have had another think, about if i can use the same principals used in making a jig for the top, in the overall machine design and i have had an interesting thought and wander what you think. ?
am using 100mm by 5 at 1200mm high, for 4 main legs at the machine corners. with very accurate bolting patterns pre cut. and patterns drilled for threaded bar. For the lengths (x,y), i was looking 2 lenghs per side of oblong profiles, like 80,160,4mm, cut at 2500mm and 1500mm.
And hers is were the idea come when considering plans for getting the frame as dimentinaly perfect as possible with simple tools. and an easy to build jig/vice.
I can build a simple jig for the bolt patterns, small, and very accurate, Lay out the lengths of 80,160. Accuratly place/fix/drill the jig at set intervals don the X and Y lengths. Doiong it like this, i can initialy ignor any twists in the metal, becuase i only need the 200mm long section were the Jig is to be accurate, so the angle of the bolt holes are perfect ( 5 pattern ). Do this for all the cut lenths and supports, accuratly mesureing were you place the jig..
Lay out the first 2 X sides, on top of 2 lenghts of 100mm/4m at 1200, with the accurate bolt patterns in, Put one bolt in each far corner to get your first square-ish, If any of the other bolt patterns line up perfect, fabulas, but not expected at this stage, Take one of you central struts, put a bolt in the top right, and if you can, bottom left, slight movement of the frame should allow this, Then, use the cheep threaded bar, to do you frame adjustments, dropping bolts in as you work outwards, at this stage, most but not all bolt points will fit.
Do this to both X and Y sides, Dont force ANY of the bolts in, only the ones that fit.
Assmble the sides and cross struts with the same principal, each accurate bolt fitted will pull the hole frame into shape, useing simple threaded bar and nuts to ajust. i should be able to get the frame very close to perfect within reason.
I would be relying on accurate mesurments over small areas, not long lenghts.
I also think there are some other good reasons for this,
1. your using shorter lengths of metal, its easer to pick out or cut reletivly straight lengths, and you still only relying on the small areas of 200mm long being dimentonly accurate, any you could probably pick them out by eye and simple tools.
2. You use the smaller lengths to pull/push the longer lengths into perfect shape, adjusting with threaded bar and nuts.
3. It would make the assembly process at lot easer that wielding, and take out any chance of the wield putting a twist in
4. could be done with pillar drill, £ 40 micro-measure from maplins, basic desk top printer.
all the bolts will only fit when it is,
It will cost a bit in bolts, but, can not see many other problems but can see lots of benefits, like stronger machine, more bolt points, simple
am on with this at the mo.
i think am going with 120 x 60mm 3.6mm with 100mm box for the legs ( 10kg per meter )
anyone suggest a good suppler of bolts,
and Devizes steel for odds and sods also do nuts and Bolts.
Special sizes and threads, Nuts and bolts i make myself using my lathe but many times i reckon its easlier Buying them.
Well, all parts cut to length out of 120*60*3.6, will spend some time overt the next few days trying to accurately cut the bolt patterns, prior to assembly
depends on how successful the first attempt works out. i will post the successful result as a individual build log, but
I have a different type of frame assembly planned, hopefully making it easier to assemble a heavy duty frame, relatively accurately. but if it goes wrong, i can disassemble and get it wielded. The idea being make an accurate bolting jig, about 200mm long. a 5 star pattern and a 3 bolt straight line. Start at the center of each length for the first bolt pattern. then accurately measured outwards for the next ones. the advantages being ;
1. your only relying on each 200mm section to be square for you bolt patterns.
2. Your not relying on your cut lengths to be totally square at the end ( perfectly )
3. As you assemble the frame, you will pull out most of the surface twists in the metal, ( as long as you have a proper assembly plan ).
then things am still trying to work out,
1. optimum bolt width/distance between bolt patterns. ( material is approx 10kg pmtr, 120x60x3.6 )
2. No of positions to plan for threaded bar/nuts to assist in initial lining up
Once initially assembled, i can then decide what parts need welding or maybe brazing, and if i have made enough places for triangles in the corners. If done correctly, the final bits bolted on should meen the frame is very close to am accurate box, and very strong. But, if am not accurate enough with the bolt patterns, it will be all over the place.
I will post any mistakes i make on this one, as i go along ( and ask for help ). then post a seporate one for the completed sucsesfull build.
Am currently considering building\buying\converting a mil to get the accurate bolt patterns. as i will need this for the head designs i have in mind. But, ther are a few companys near me that can mill metal to the accuracys i need. So i need to get proper prices first from them.
Dont forget to drill a pin hole near the bolts, at the end i mean. Once assembled and centered and shimmed, you drill and hammer a single pin there at each assembly. That will help eventual disassembly and assembly in the future.
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