MK1 Steel router build log 1500x800x200

[driftspin]

Next question.

M5 bolts for rail and carriages .

Will a typical hex 8.8 / 12.9 m5 x20 do?

What did you guys buy?


Grtz Bert.



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[Clive S]

Next question.

M5 bolts for rail and carriages .

Will a typical hex 8.8 / 12.9 m5 x20 do?

What did you guys buy?


Grtz Bert.



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Remember the F length 30mm is in the total length on the screw.

The bolts used are generally cap heads

[Boyan Silyavski]

Next question.

M5 bolts for rail and carriages .

Will a typical hex 8.8 / 12.9 m5 x20 do?

What did you guys buy?


Grtz Bert.



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Din912

[driftspin]

Remember the F length 30mm is in the total length on the screw.

The bolts used are generally cap heads

Hi Clive,

Yes, i discussed this with Fred.

He is a patient guy .

I want some spare cm of travel in the Z design... i am not sure i like the height of the z axis though.. I like compact.

I want the extra head room in z ballscrew for MK1a gantry...

what ?!!! NO NO NOO... 🤤🤤🤤


No.. im not sure 80x 120 will do and calculate in a design change to a more beefy gantry ....some day... with more travel...


Well i want at least 200mm +Z travel.. so

Travel + nut + bf bk + F = 30 for pully =
+/- 320 .. so 350 for Z should do.



Grtz Bert



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[driftspin]

Din912

Yes those.. exactly.

But... 8.8 or 12.9

Like your good ol bolts or tougher machine bolt style.

Does one need high tensile strenght?

I will be tapping in the 4mm steel from box section for the rail. all 200 or so off them.

Carriage bolts will have some extra meat to grip on to (4+5 mm) it has less bolts so ... well more doesnt hurt there.

Grtz Bert.

PS
Where does one buy kinda good machine taps for this purpose, not sure what makes an economical machine tap.








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[Clive S]

Like your good ol bolts or tougher machine bolt style.

Does one need high tensile strenght?

Just standard cap heads black or zinc etc.

Cutwell do good taps.

[routercnc]

8.8 means tensile strength of ~800 MPa and yield strength of ~80% of this

12.9 means tensile strength of ~12 MPa and yield strength of ~90% of this

So 12.9 will be much stronger than 8.8 but you are usually not interested in that. You are unlikely to create forces high enough to break the bolts on a diy machine. 8.8 MPa is quite a lot !

What you are interested in is the stiffness of the bolts as this tells you how much deflection you will get when machining parts. But this will be similar in both bolt types so 8.8 will be fine. No harm in using 12.9 but they won't give you any benefit.

If you are interested in why it is because the stress/strain curves have the same slope, it is just that the 12.9 bolts will go further along the curve as they are stronger.

If you buy stainless there is a different naming system as stainless does not really yield before it breaks (by comparison) but again there is no diy CNC advantage other than looks nice and won't rust

[driftspin]

8.8 means tensile strength of ~800 MPa and yield strength of ~80% of this

12.9 means tensile strength of ~12 MPa and yield strength of ~90% of this

So 12.9 will be much stronger than 8.8 but you are usually not interested in that. You are unlikely to create forces high enough to break the bolts on a diy machine. 8.8 MPa is quite a lot !

What you are interested in is the stiffness of the bolts as this tells you how much deflection you will get when machining parts. But this will be similar in both bolt types so 8.8 will be fine. No harm in using 12.9 but they won't give you any benefit.

If you are interested in why it is because the stress/strain curves have the same slope, it is just that the 12.9 bolts will go further along the curve as they are stronger.

If you buy stainless there is a different naming system as stainless does not really yield before it breaks (by comparison) but again there is no diy CNC advantage other than looks nice and won't rust

Ok guys i'm clearly not into engineering like you all are

Getting there... some day... maybe.

ok welded in braces today..

Now some more degreasing and set up for pouring.


Will post soon.




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[Nickhofen]

Looks good!

[driftspin]

Looks good!

Update

Last steps welding .

Prepping stuff for pour.

Idea is to use simpel floor board and silicone kit to leak proof..




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