MFT/3 Profile image and measurements

Andi said:
I am actually considering which is the best method to connect them to a wooden base.

I got an ink pad, press it against the end of the extrusion and then pressed some paper onto the end. Then I had something to measure. Primitive, but it worked!

This may not fit in with your design; I bolted the extrusion to a timber rail. Holes were spaced at about 200mm, alternating between (C+D)/2 - A and (E+F)/2 - A  from the top of the rail (see Garry's dimensions - calculations to be checked on-site). I then put the bolts in and loosely fitted the nuts. I could then slide the extrusion in with each bolt head going into either the top or bottom groove at the back of the rail. Fasten bolts. The top of the rail should be flush with height 'A'.
 
I was designing my second t-slot extrusion workbench and was curious to compare rigidity of 80/20 extrusions to that of MFT.
Using the image [member=11629]GarryMartin[/member] provided I calculated Moment of Inertia for MFT profile cross section.
Here it is: Ix = 10.5cm^4 and Iy = 19.4cm^4 (this is for x and y axis respectively).
For comparison
40x80 mm light 80/20 extrusion: Ix = 19.5cm^4 and Iy = 71.3cm^4
40x80 mm standard 80/20 extrusion: Ix = 25.3cm^4 and Iy = 97.3cm^4

I.e. 80/20 is 3 to 4 time more rigid than MFT.

For illustration 1 meter long extrusion supported at the ends with 500N ( 112lb) load in the middle will deflect:
40x80 standard  -  0.15mm
40x80 light -        0.2mm
MFT -                    0.7mm
 
For anyone hunting for a rail in the UK - or indeed any obscure spare part for a tool or machine, I highly recommend Miles Tool and Machinery Centre in Yeovil.  Web site is at mtmc.co.uk

They're an excellent resource as they show you the manufacturers tool part diagrams along with part numbers, the cost, and a button to add the part to your shopping cart.  Saves a whole bunch of time!!  [thumbs up]

The MFT page is here >>>http://www.mtmc.co.uk/Product.aspx?ProductID=94023

You'll see that the long rail is part number 5 and currently costs £58.88 plus VAT

 
Back
Top