How would you fasten back to back carriages?

I am changing my gantry and Z plate design, I am now trying to put the rails on the front face of the gantry instead of top/bottom.
The problem is now that the carriages for the Z plate and Gantry are in conflicting positions, How would I be able to fix them at opposites?
The only way I can think is by attaching the carriages to a plate with a flange and bolting through the flange onto the existing plate but this will increase the thickness of the assembly, any ideas?
If I move the Z plate carriages up by 44m that will allow me to bolt both carriages but it will also mean the cutter will be 44mm further away from the bottom of the bearing reducing stiffness!

Very simple. leave the back ones/ gantry side/ as they are. Draw over sized aluminum plates for each bearing block. Draw recess in the plate, if 20mm recess it 15 or 10mm. So mount the plate on the back ones, then mount the plates with the front ones. It could be done with big plate for all but i assume you want to minimize overhang as possible.

However i would reinforce your plate with 2 ribs each side, long as the plate and say 30mm high, so they don't interfere , against plate bend. if possible i mean.

Attachment 13298

PS. Anyway, if you make 2 vertical plates for each pair of blocks, they can be used instead of further reinforcing the big plate, instead of the ribs i mentioned. As they will add thickness vertically

Use threaded bearing blocks for the Y axis, that you can bolt the plate onto using counterbored holes.
Then use unthreaded blocks (Bottom mount) for the Z axis and bolt them on from the outside.

Attachment 13299

The HGW-CB/HB type then, I wonder if Chai has them?
Cheers, charlie

The wide type ones, holes don't clear when crossed. Only the long narrow type.Size 20 i mean .So HGH not HGW. Thanks Gerry, i always have thought that they will not fit, but it seems was wrong
Attachment 13306

Hi Silyavski, the long ones holes dont cross but the hole to get the capscrew in would still be obstructed by the opposite carriage but the ones with the flange on the side will allow me to attach them after fitting the opposite bearing.
Cheers, Charlie

I'm a bit confused, looking at hiwins dimensional section in the spec sheet for the HGW-CB/HB carriages, it looks like they still bolt from the underside, it doesn't look like they have a through hole but also looking further down, the A/B at the end denotes top or bottom mounting so I think the drawings wrong?

I believe that the CA and CB are threaded,and CC has through holes.

Hmmm, and yet on the picture you posted further up it shows the 'B' having the through hole, think I will have to make sure before I order anything because 4 wrong carriages aren't cheap!
Cheers, Charlie

I have some of their older models "C" type, still in the boxes. I'll have to check, but I thought that they were not threaded.
But yes, in the image, it looks like B is not threaded.

Yes, my "C" type blocks are threaded. I think you'd want to use the "A" type for the Y axis, and the "B" type for the Z axis.