UK Build

[gazatteer]

Hi

Does anybody know of any UK suppliers who supply standard imperials sizes of steel, aluminum and fasteners. I have spent all day today visiting some big metal and fastener suppliers around my area but without any luck. They don't supply the imperial measurements and if they do then the sizes required for momus CNC are not stocked.

The fasteners, are they UNF or UNC or some other standard?

108" 1/4" thread seems very long. Is this correct?

thanks
Naeem

[supermet]

Hi

I got most of the sizes of aluminium and all the steel from a local stockist. I will have to check my paper work. You can get all the aluminium sizes from the internet but some stockists have minimum lengths and then postage!
I converted all the threads to metric course standard, much easier to get all the fasteners and I had the taps already.
My build is going well all metal work and base complete gathering all the electrical and belts together now. My parts from dumpster CNC arrived today but with a customs and handling charge!!
If you needy help with the metal I can copy you my parts list for the aluminium and steel with the sizes I have used when I can find it.

Dave

[gazatteer]

Thanks Dave
I would be greatful if you could share the list of your suppliers.

I went the local specialist of fasteners and they suggested I was better of buying a £13k CNC from their catalogue. They didn't understand the American measurements for bolts and nuts and thought that they had to be precisionly made using specialist machinery.

Won't the imperial thread conversion to metric course standard affect the precision of Momus CNC?

Did you convert steel, aluminium and plywood measurements from inches to millimetres? Did you get the closet British standard of steel and aluminium? Won't this affect the precision of the CNC?

Yes please. I would be greatful for the parts list for steel and aluminium with the sizes.

My background is in software development but I have access mechanical machinery at work, which includes lathe and milling machines and all types of tools including taps.


Thanks
Naeem

[OCNC]

Thanks Dave


Won't the imperial thread conversion to metric course standard affect the precision of Momus CNC?

Did you convert steel, aluminium and plywood measurements from inches to millimetres? Did you get the closet British standard of steel and aluminium? Won't this affect the precision of the CNC?


Thanks
Naeem

The precision won't be affected but you'll have to make the necessary adjustments to keep the relative spacings correct so that the bearings will locate on the rails properly. Other than that you just need to look for interference issues that might affect ease of assembly or motion. If your final sizes are close to the spec's this probably won't be an issue but still it's good to be aware of it. If you study the drawings a little bit you should be able to see what the general principles of the mechanism are and how it's not really an 'absolute' type of design. Any of the dimensions can be varied to get a 'custom' result as long as certain relative parameters are maintained.

Chris

[gazatteer]

Thanks Chris

I have found some suppliers of steel, aluminium and fasteners but unfortunately they don't stock all the sizes.

I will start the conversion of imperial threads to metric coarse standard.

I will order the steel, aluminium and fasteners by this weekend.

I will start my project with the plywood base.
What type of woodscrews do I need?
Where can I get 4d bright finish nails? Are these for the plywood? What is British version of these nails called? What size are these nails?

Thanks

[OCNC]

Thanks Chris

I have found some suppliers of steel, aluminium and fasteners but unfortunately they don't stock all the sizes.

I will start the conversion of imperial threads to metric coarse standard.

I will order the steel, aluminium and fasteners by this weekend.

I will start my project with the plywood base.
What type of woodscrews do I need?
Where can I get 4d bright finish nails? Are these for the plywood? What is British version of these nails called? What size are these nails?

Thanks

Thread conversion: M8 x 1.25 for 5/16"-18; M6 x 1 for 1/4"-20; M5 x 0.08 for #10-32.

A 4d finish nail is a headless nail (or nearly so) that is 1-1/2" long and about 2mm in diameter. There is nothing particularly special about any of the fasteners that are used to assemble the wooden base. Many substitutes would be suitable that would get the job done. Using glue is important though. In many wooden assemblies glue becomes the most important fastener with the nails and screws providing more of a clamping and locating function until the glue sets.

Chris

[supermet]

Naeem

Hope the attachment may help. The only different size material was the angle iron I could only get metric sizes and used 30 x 30 x 3mm. The rails want to cold rolled bright rectangular bar not black bar this is for the angle iron only make sure your supplier is aware of this or they may try to supply black bar which will not work.
I used imperial measurements for the metalwork and metric for the woodwork as the plywood is supplied in metric. Make sure you measure your ply thickness as it can be different to the sizes quoted I ordered 18 and it was 16mm!
I printed the instruction manual and keep it a file I then printed all the parts drawings to used as working copies.
Also before you start view the forum as there are lots of good tips. I changed the bolts sizes on items 16/1 & 16/2 & 22 & 23 from 6mm tapped holes to M8 nuts and bolts.
The fixing of the x rails items 32 and 34 to the base I used M8 bolts but you need to move the end sets of hole so you don't need the coach screws (lag bolts).
The bill of materials has some different terminology than we used on this side of the pond the set screws are what we call grub screws and you don't need 100 either as they are used for adjusting the bearing axles.

Got my belts and pulleys and cut the grooves in the clamps to suit the belt I have used a T5 profile timing belt and matching pulleys.

Dave

[gazatteer]

Thanks lads. I really appreciate your help. Steel is last on my shopping list, see below. I'm hoping to go shopping for plywood tomorrow. Will start of with plywood as recommended.

Apologies for the late reply. I have been very busy with work and shopping for momus materials.

MetalSupermarket quoted me just under £280 (about £30 for steel and the rest for aluminium) for steel and aluminium materials listed in "bill of materials" in momus drawings. The price of three aluminium materials stood out from the rest as it totalled about £100. I just felt that it was too high and I walked out of the store without making the purchase.

I started searching the Internet and eventually found ForwardMetal, who quoted me, wait for it.... just £94.50 including delivery

Wowwww that is a saving of over £150 even if I buy the steel from the expensive MetalSupermarket.

I have been very lucky. I have access to CNC milling, lathe, surface grinders and loads of other machines, at work. I have been on work experience for couple of months in the mechanical team. I have learnt a lot. I even created couple of parts, including part 20 Z motor mount right, using a CNC milling machine. The part was just 0.5mm big because drill bit measurements were wrong. Overall, I was very satisfied. I will use these machines to make the parts during lunch time.

Thanks again
Naeem

[gazatteer]

I have bought plywood and aluminium.

The plywood cost me more than I expected because the minimum size plywood sheets is 5x5feet, which is way more than I need for this project.

Cost so far £111 (plywood) + £94.50 aluminium. I reckon I should have bought the plywood for half the price but you can't win all the time. The surplace plywood is listed on eBay so am hoping to get something back.

Anyway, I am aware I need to convert thread measurements to metric but what I am still unsure about is the holes, just holes not threaded. Do I need to convert the holes to metric since I will be converting the threads to metric?

Thanks

[OCNC]

I have bought plywood and aluminium.


Anyway, I am aware I need to convert thread measurements to metric but what I am still unsure about is the holes, just holes not threaded. Do I need to convert the holes to metric since I will be converting the threads to metric?

Thanks

You need to have the same clearances and fits that you would get with the imperial dimensions.

Chris

[gazatteer]

You need to have the same clearances and fits that you would get with the imperial dimensions.

Chris

Thanks Chris

Hopefully, I will make a start this weekend by converting all holes and threads (aluminium only) measurements to metric coarse.

Will also try to draw out the dimensions on plywood.

thanks

[gazatteer]

I have been looking at converting the measurements to imperial to metric coarse and I have come to a stop on first part.

The diameter of 1/4-20 stud is 0.2500 (Zeus Precision book). This stud goes through part #1 (gantry left bottom) hole. This hole diameter is 0.3125. This looks like a too large clearance hole for 1/4-20 stud. The 0.3125 hole is not listed in Zeus Precision book for 1/4-20 screw thread. Here is what is said in Zeus book:

Desig'tion 1/4-20
0.Dia. 0.2500
Core Dia. Nut 0.1959
Core Dia. Bolt 0.1887
Pitch 0.05000
Depth 0.03067
Effec. 0.2175

Is 0.3125 clearance hole correct?

The closet to 1/4-20 in metric would be M6 (I think). I think the clearance for M6 is 6.10mm. Which is a lot less than 0.3125inc. What are your views on this and what should be the clearance hole diameter in metric?

Please advise.

Thanks