The holes on the scanned paper templates I provided were drawn on with pencil through the holes in the original mount, so they are a bit smaller than the necessary 10.5mm diameter. They're just there to provide approx positions however.

SAS

If you use Sidewinders dimensions from the CAD extract you'll find the hole centre's as marked on the paper templates are pretty much cock on. After checking them I centre punched for the holes through the paper. I didn't have a 10.5mm bit, just a 10.0 so I bodged it a bit by enlarging the 10mm holes by wiggling the 10mm bit in the holes until the M10 bolts fitted through!

Didn't heat it first as no heat source. My welder is an arc (stick) one, not a gas torch. I thought about holding it in the kitchen hob flame for a bit but my wife was in!! May well have helped though.
Yes 10.5 holes for M10 clearance. I had to get some 70mm bolts as the 65mm ones that came off the MGF were a bit short, possibly because I used 6mm steel for both parts but may have been a bit short anyway.
I checked on my Autocad at work today and it doesn't seem to have an export to or save as choice for STEP files.

"I thought about holding it in the kitchen hob flame for a bit but my wife was in!!"

Some people really have mixed up priorities don't they..

Thanks for checking the STEP thing, I'll just bookmark the thread for reference when I need it.

Update on the PG1 bracket - bit of a problem! My bracket has broken. Its a brittle fracture that goes through the two holes at the top that fix to the metro square rubbery thing. Two most likely possibilities seem to be that 1) I overheated the steel during welding making it go brittle or 2) It was Toffee chinese steel that was already brittle. Bought off ebay so who knows. Might have been a combination of the two.

As it broke through both bolt holes the engine/gearbox dropped down pivoting around the remaining mount on the right hand side. In dropping down it pulled the short driveshaft out of the diff so I lost all drive and a fair quantity of gearbox oil came out through the driveshaft hole. Luckily my adaptation of the original Metro steady bar bush was the lowest part and that touched down first so stopped anything more sensitive from dragging along the road as I came to a stop. Miraculously the flailing driveshaft doesn't seem to have done any damage, other than to itself - the inner CV came off altogether!

I've marked up on an old photo of the bracket where the fracture is:


Not pretty:


I was able to jack up the gearbox and hold it up with a strap and then got a mate to tow me home as luckily it was only 10 miles from home.

Although mine was a home made bracket it might be worth checking yours in case there is something about the basic design.

It looks a mess mate but I think you got lucky here, it could have been so much more worse if you was going at speed as well.

You'll have it back together soon, I'm sure.

As Colin said I think you're lucky it wasn't worse and you're capable of repairing it.

Having said that I went straight out to the garage to check mine as it's one of the oldest around, 1998/99 and 70K miles now. and it looks absolutely fine.

To break like that would suggest that it's under stress wouldn't it? Has the rubber bush been filled in with resin? Mine's not.
Have you got an 1.8 steady bar as well as the adapted 1.4?

Bob.

It was as I opened it up at the exit of Quarry at Castle Combe so I wasn't going particularly slowly at the time!! On the positive side it was quarter to five so only 15 minutes of the track day lost, but the red flag I caused closed the track early for everyone so I wasn't popular among the guys who usually stay out 'till the chequered flag...

My rubber mount is standard - i.e. loose and floppy. That's one of the things I'm struggling to understand as I'd have thought all the movement in that area will be taken by the bush leaving very little stress on the steel. As its less than a year old it can't be a fatigue problem. It definitely looks like a brittle fracture so must have been due to internal stresses within the steel itself relieving themselves at the weakest point through the two bolt holes. That's why I'm thinking it is either overheated steel or it was brittle from the start. From what I've read it would need to be heated to over 1500 degrees to turn good quality mild steel brittle through overheating - might have been that at the weld itself but I can't see how it could have spread that far but who knows. Brittle fractures are more usually associated with high strength carbon steel rather than mild steel, which should fail by ductile tearing rather than brittle fracture. I'll try to temper the new one I make by putting it in the kitchen oven at full temperature straight after welding then letting it cool very slowly.
The more I think about it the more I'm thinking it was poor steel. I didn't understand the difference but have now checked ( and read up) it was made from black steel. Black is rolled into plate whilst still hot (almost molten) and doesn't undergo any further heat treatment. The bit I've bought to make the new one is cold drawn mild steel - this has further processing including a degree of annealing so should be much less prone to brittle fracture and is what I should have used originally!

I don't have the 1.8 steady bar - as my car was built as a 1.4 I only had the 1.4 bar so adapted that. I have toyed with the idea of a second steady bar...

When I upgraded to a VVC I was able to purchase a 1.8 steady bar [good old days] and adapted the 1.4 steady bar as well.
I found there was a lot of engine movement with only the 1.4 steady, maybe that's added to the problem, certainly doesn't move with two bars.


Bob.

New bracket roughly cut out, welded and in the kitchen oven in an attempt to let out any internal cooling stresses gradually!
I've left a bit more metal around the top fixing hole area this time.
I'll round off the edges and drill the holes another day!

Sanzo you should have had a beef joint and a few roasty potatoes in there at the same time it all helps the molecular structure
John

Make sure all edges holes & surfaces are smooth and 'notch' free, even small ones are stress raisers and can aid initiation of crack formation.

SAS