Heatsink for Two Transistor Forward FETs?

[Faringdon]

Hi,
We need to heatsink the two TO220 FETs of a 90-265VAC, 130W Two Transistor Forward.
We wish to have them both screwed to the same  aluminium block.
The block will be 16mm x 11mm by 25mm high.
The FETs will be screwed on the two 25mm by 11mm faces. (The TO220 FETs will be vertical against the opposite faces as described.

This will be a custom heatsink, as there is nothing offtheshelf.

How much do you think it would cost to make this?
In quantities of say 5000?

It will have a M3 hole right the way through for the screw to which the tab nuts will be screwed on.
So that screw has no head as  it will have a nut each end. (the hole is not tapped)

[Gyro]

Find a metalworking shop  --> Get a quote! ... and give them a drawing.

[Kean]

It will have a M3 hole right the way through for the screw to which the tab nuts will be screwed on.
So that screw has no head as  it will have a nut each end. (the hole is not tapped)

The assembly workers are going to love this... 

BTW, if it is not tapped, then it is not an M3 hole.

[SMTech]

It will have a M3 hole right the way through for the screw to which the tab nuts will be screwed on.
So that screw has no head as  it will have a nut each end. (the hole is not tapped)

The assembly workers are going to love this... 

BTW, if it is not tapped, then it is not an M3 hole.

Won't they just, equally ***ing why? If there's space for a nut & the tool to tighten it, there is space for a head.

[ArdWar]

Stuff like this is why everyone are shouting to you to just buy COTS modules.

[jc101]

How much will the custom-cut threaded rod cost, and how will you ensure it's secured in both nuts adequately?
What will this aluminium block be fixed to, or will it just be floating attached to the TO220's?

Please only reply if you can attach a drawing with sufficient detail.

[ArdWar]

To be fair ~20mm M3 set screws are pretty common, and the slots (or inside hex) may help with fastening both sides. It's just that it'll be three stage process with at least two different tool working simultaneously from opposite sides.