Rose joint caps complete

 After a lot of welding, cutting, grinding and more welding, I finally have my rose joint caps. Two layers of 5mm steel with a welded 12mm nut on the back, giving 22mm of fully threaded end;

A quick check against M12 bolts shows everything looking good;

And here they are in place on the tubes, with the rose joint screwed in and the hoop mounting brackets ready to go (more 5mm steel);

I'm happy with the work, it all went to plan and while it probably won't pass MSUK inspection I can see enough metal at every stage to ensure that it will help if the worst happens. The next stage is to cut the bars to length and weld the fixing plates in place.

Talking of welding, I went back over the cross bar on the roll hoop and fully welded it;

Unfortunately, while I was happy with the weld itself (reasonably tidy and with good penetration), it did pull the hoop in and stopped the fixings from matching the holes. I had expected it when welding the hoop itself, so I guess it was just a delay to the inevitable. I needed to slot around 3mm into each of the eight holes to cover the shrinkage, so now the fixings have washers underneath them. It's still as strong as before, the washers are 'belt and braces' so to speak.

Now comes a little frustrating bit. I wanted to look at how the tank was going to be strapped in, compared to the support bar mounting plates. I managed to get it wrong;

The fuel tank sits on top of the plates on both sides. This means that once the tank is strapped down, those plates will not be as easy to work with. Particularly when I'm inside the boot of the car trying to wrangle the support tubes into position, I don't want to have to fight the fuel tank as well!!

Of course, it's a fairly easy fix here, I just need to trim the plates a bit. I do have the trailing edge that is already shorter, and rotating the plate showed that it would work. It's just one extra job.

I've also remembered to fully weld the bodywork mounting on the drivers side, so that's now ready to go. I think for next weekend I'm going to get hold of some Sikaflex and get the bodywork in place. So before then I need the support bars finished. 

I also want to get the straps sorted for the tank. For some reason I thought the fuel tank straps were going to be soft, turns out the book asks for 2mm steel. Of course, I don't have 2mm steel, and definitely not in the length required. B&Q have it, and while it seems to be a bit expensive it appears to be the 'normal price' for steel now. I knew I should have got this finished a while back, all these little bits are going to end up costing more than most of the chassis. The tank also needs insulating from the rest of the chassis, so I need to find a rubber strip of some kind. 

The next post will be having a look at the next jobs, or more importantly the next purchases. There's not much left now, it'll be on to engine and body work. It's looking to be a nice summer (fingers crossed) so that will make things easier to bring things out of the garage to work on. Of course, we have thunderstorms predicted for today, so just indoor stuff for now.

Rose joint install

 For the roll bar supports, the rose joint mounting is going to be crucial. It would be ideal if it was fully threaded, but I've got no way of turning a suitable insert. So I want to get as close as possible with the options I have to hand.

What I've decided on is an M12 nut, mounted on the back of a 5mm plate that will be welded just inside the tube. I will then have a second 5mm plate welded to the end of the tube. That gives me about 20mm total threaded surface, with an end plate that is double the thickness of the tube itself. The rose joint is then inserted along with a lock nut. 

The only problem with that design will be the multiple layers and how the thread will work between them. Ideally I need to weld up the three layers away from the tube, then cut the thread. That will allow me to match the thread on the nut. If I do that I'll be installing a 'top hat' into the end of the tube and only having one weld to the tube. It also means the weld between the plates will most likely need grinding away as well, again for the top hat design.

What I'd prefer to do is weld the nut to the smaller plate, cut the thread on the smaller plate, weld that into the tube, then weld the larger plate on top. But while I could cut the thread on the smaller plate, I couldn't do anything with the larger plate. 

Thinking about it, the best option would be to weld the large plate on then tap from the other side. I'll have to do a bit of work on that one to see if I can get the tap all the way through the tube, initial thoughts would be to fix the tap into a socket then use extension bars (or even a length of steel) to get the tap all the way along the tube. I might try that step first to see if it's viable. 

(later that day...)

I think I'm overcomplicating things. I screwed two spare pieces of metal on to the joint along with the bottom and top nuts. It left me with about two threads spare so I think it's perfect for the end cap. But I am going to do the whole thing off the tube first, weld all the layers together then tap straight through. As long as I get the holes in line then it'll be the strongest way of making the cap, then having only one weld to the tube will be less of an issue. 

So it'll be a fixing plate that is twice the thickness of the tube, and a total thread length twice the thickness of the joint. Then it'll need welding to the roll bar hoop, that should be pretty easy. I suspect 3mm plate will be best here, fully welded of course. 

Picture time!

 Time to post some pictures, first some useful ones. In the previous post I said I wanted to move from the bracket idea to the rose joint. This is what I'm aiming for now;

Now it does create a potential weakness in the roll bar strut, but it gives me more flexibility in the mounting. As long as I can get the rose joint securely screwed into the end of the support tube then I think it'll work (more on that later). 

Oh, one more picture from the same set;

Using string to find the route of the tube is a brilliant idea, it means that the hole starts small enough to make corrections before the bigger hole is cut. I'll be doing the same for mine. 

Now on to the show. Malvern as a showground certainly has it's advantages, not least of all it's location;

Nothing like blue skies and great scenery to really start the day off well!! 

First was the ANC Replicar, something I've seen multiple times and often turn to for inspiration. This time it was the finishing of the lower bodywork that caught my eye;

I probably won't copy it directly because I'm hoping mine will be boxed in, but it's good to see a strip of rivets used for a secure mounting.

The next photo was an idea for how to trim the boot;

This is just a fibreglass mould but it gives a nice usable finish to the boot space. I'll look at that probably after IVA?

Next was a method of boxing in the wheels. With the bodywork as it is, there is no protection at all from road debris (even a bog standard seven has wheel arches whereas I don't). This car is an example of how I'm planning to sort the arches;

Next, a bit more trim. This time behind the seats. I like the idea of plain aluminium that I'm working with at the moment, but in case it does there is always carpet. This is a pair of replicars, one with plain panels and the other with carpet;

It also shows examples of rear view mirrors (side and centre) which I will no doubt be following.

Next came this beautiful machine. It's an old version of the Healey (and it's a 100 rather than a 3000), and really gave me lots of ideas for how things will look in the end. I had a great chat with the owner who clearly had a lot of enthusiasm for his car. 

At this point I realised that I didn't have the measurements for the indicator or tail lights. While I can reuse the donor headlights, I don't have anything close to the other lights. I'll add that to the shopping list for Newark!

The one thing we did talk about was the number of sharp protrusions and corners that may have been ok at SVA (when he had it tested) but work with IVA. This car doesn't even have head restraints, and the spikes for the roof would never get past an IVA. But as with most kit cars, getting through IVA is one thing, the modifications afterwards are what makes it more like the finished product. 

He also mentioned a second one at the independent stand, and considering I didn't know these replicas existed I had to go look for it. The search didn't disappoint;

 This one had a bit more money thrown at it and you could tell, although I'll be happy if my car ends up even reasonably close to either of them. There was lots of little details on this one, like the chrome surrounds for the roll hoop. Of course the RAC badges and the rail is a nice touch, again for post-IVA.

Purely by coincidence, the next car I found was a Sebring in the same colour scheme, which made an interesting comparison;

I do like the Sebring cars, although just looking at this price tag shows they're in a different price range to what I'm dealing with. If they were still around I'd be looking at 25K to put one together. 

On the same independent stand there was another example of a car with a hinged bonnet and deflectors for road debris;

I don't recall the type of car, but as well as the flat plate deflectors under the bonnet there was also a very tidy exhaust install. The flexible joint out to the side mounted exhaust was well thought out, and the side mounted silencer looked really nice. No sign of a cat thought, which considering it was clearly an MX5 engine was quite surprising. Maybe the donor was just old enough to not need one?

The bonnet hinge here had some nice touches, like a metal wire to the engine to stop it swinging too far forward, as well as the foam tape on the body for it to sit on when closed. 

Todays progress

 After yesterdays trip to Malvern for the kit car show, I had a lot of ideas on what I want to do next. Photo's to follow, but first a progress update and thoughts on an issue.

Today I have;

1. Welded the driver side body outrigger.
2. Finished and tacked the cross bar for the roll hoop. 
3. Tacked on the rear support for the rest of the roll hoop.
4. Started to look at the brackets for the rear supports for the roll hoop. 

I'll come back to these in order, with photo's, but number 4 has left me with a problem. I got some brackets from the tube bender, on the basis that even with the slight angle I could still weld things up and get it working. Unfortunately that's not the case, even with a bit of trimming it's just not going to work. And on top of that, they are really ugly!! It's a big chunky thing with sharp points and just not what I want for a highly visible part.

However, I did see that Westfield use a rose joint as part of their roll hoop, there were quite a few of them at the show. A quick check on their page, and there it is, a 1/2 x 1/2 rose joint. It's a tidy solution, just requiring the rose joint itself on the end of the rear stay and two plates welded to the roll hoop. I already have 3mm plate so some brackets won't take long to weld up. 

But of course it's UNF, and I would prefer to stay metric. On this page there is a dimensions table https://www.mcgillmotorsport.com/1/2-x-1/2-unf-right-hand-male-xmr8-ultra-high-performance-rod-end-c-55-p-53. The 1/2 refers to the internal diameter of the hole, with the outside diameter being 1.3 inches (33mm) and the overall length being 2.4 inches (61mm). So the closest metric would be an M12 x 1.75 such as this https://www.mcgillmotorsport.com/m12-x-1.75mm-right-hand-male-xmrm12-ultra-high-performance-rod-end-c-55-p-257. Since McGill do free postage I'll get two of those.

So overall it's been a decent weekend, apart from a few more bumps and bruises. I'm not sure why but I seem to be extra clumsy lately. Hopefully it'll clear up at some point.

Right, that it's for now, I'll put a few more notes and photos during the week. 

Roll bar hoop installed

 This weekend was very productive, I managed to end up with a really painful ankle after a piece of wood jumped out and bit me, and half a pinkie fingernail missing when a piece of metal that I was drilling decided to grab and spin... Anyway, on to the real purpose of the weekend.

The first job was to cut some mounting plate from 3mm plate, then drill the holes for the bolts. That was pretty simple, and meant I had a platform for the roll bar;

Supporting the hoop from above I could see roughly where it would sit, but I could also see that it wasn't even. Not overly surprising to be honest, I specifically asked for the material to be cut at a right angle. It's clear from the pictures above that there was too much of a gap, and it was quite clear that one leg was longer than the other. 

Once I'd figured out how to measure the tube, I was able to cut and profile the ends. Oh, cutting roll bar tube with a hacksaw is an exercise in futility! The angry grinder and cutting disc came to the rescue, although I was still giving myself about 20mm of grinding and profiling to do. 

Eventually I got it level and flat across the surfaces, so I mounted it back on to the car. At this point it occurred to be that I can gain myself a few centimetres in order to increase the angle between the hoop and the brace. I therefore moved the roll bar forward on the plate until it was inline with the bolts. A quick tack and weld up, and this is what I have now;

The tube still sits within the four bolt pattern, but it's closer to the chassis frame which hopefully is a good thing? I can do the same with the rear braces, move those backwards. Every couple of inches gets me another five degrees, so with this being one inch forward I'm halfway there. Obviously I'll never go racing in this (maybe a track day at most), but at least if I aim for what MSUK suggest then I can have a bit of peace of mind. 

One thing I did note that despite me getting everything really hot when welding, the bolts loosened off really easily. There was no misalignment or similar issues. I thought I had twisted something when I started tacking it up as the right hand side had deflected a few mm. but after bracing it, welding it up then letting it cool it all settled down into a good position. 

For the rear braces it's back to the frame;

This was a little easier, with the frame not yet on the car I was able to cut and drill the plates for the braces without having to contort myself across the back of the car. Once this is welded up and on the back of the car I can finish the roll bar. Oh, I did notice that the passenger side plate doesn't quite line up anymore due to the captive nut weld, I'll have to bear that in mind when I finish the welding (they're only tacked in place at the moment). 

However there is a sequence to follow now. I want to get to the back of the car, which does mean that turning the car round in the garage would be the best option. But the bodywork supports can also benefit from the car being the other way round. So next job is to tack on the side support that is visible, then spin the car, then do the other side support and the rear. That way I can have the roll bar done and the bodywork support ready to go at a similar time. I still need to understand how the braces go through the bodywork, especially with the saddle clamps that I'll be using.

Oh, on the subject of saddle clamps...  I can see how they would fit and I think they'll only need a small amount of trimming to get the angle. It's going to be how close I can get the braces to vertical that'll be the tricky issue. Too far along and the angle will be off, but too close to the bend and it'll be the bend itself that causes the saddle clamps to need adjustment. And I've just thought of something, I need to find the centre line of the roll bar. Logic would suggest that it's the centre line of the car, but even that isn't straightforward. I might get the centreline sorted tonight as a mini-project, I won't have enough time to get all the welding done and turn the car around. Tomorrow I'm in the office and Wednesday will be making planters for the front garden. 

Real roll bar

 After deciding how things were going to be set up, I placed the order. And here it is!

OK, yes it's just a bunch of tubes at the moment, but just by the weight of them I can tell they will do the job.

A big shoutout to Race Spec Cages, AKA Tube Bender on Ebay. I asked about the removable links between the hoop and the struts, and he suggested the clamps could work even though it was off centre. The clamps are lying on the hoop in the picture above. With a solution for removable links in hand I went ahead and ordered it. It cost me £140 all in, which is roughly what I expected for the three bars, the bent hoop and the brackets. 

A quick fit against the drain pipe version shows that it's slightly taller, which isn't a bad thing. I've got to finish the ends ready for the plate, and the struts are actually long enough to reach the taller hoop so I'm tempted to run it at the slight height increase. It doesn't affect the cross brace, as you can see in the photo I requested a bar long enough to fit anywhere in the hoop. 

Next step is to make the mounting plates ready to weld to the bottom of the hoops and struts. Then I'll level off the hoop and angle the ends correctly, then start lining everything up. It's a fair bit of work to be honest, but it's a nice 'isolated' block. I don't have to rely on anything else included in the test fit.

Of course, it'll all change when the bodywork goes back on as I'll need to thread it through, but that should be a minor challenge. 

Oh, and it all needs cleaning! It's all scaled up and oily, as you would expect out of an engineering shop. A quick degrease then ten minutes with an appropriate cleaning disc on the angry grinder will sort it. 

Tank platform and roll bar brace

 This weekend was another busy one, bringing out the rear of the diff cage to provide a good platform for the fuel tank and somewhere fort he rear braces to go. 

The first thing that had to change was the position of the roll bar support. I had originally planned it for right on the corner of the fuel tank like this;

But in real life that wasn't going to be possible. The platform for the roll bar would be sticking out into thin air and very difficult to support. Instead I went for bringing in the support to line up with the tank;

Using 1 inch steel in a U shape off the back of the diff cage means that both the fuel tank and the roll cage support get some pretty beefy metal. I reproduced the roll hoop base to make sure it's consistent, so it's a 110mm pad with 70mm bolt distances. The whole thing will be braced to the bottom of the diff cage, and I also cut some more 3mm plate to form a box. That might seem a bit 'excessive' but does that word have meaning when it comes to roll cage strength?

The only doubt now is that the angle of the bar is lower than MSUK yearbook requirements. It's sat at 25 degrees instead of the required 30. To get the 30 degrees I'd have to move it back 50mm. That might be possible if I can get the captive bolts in place inside the rear tube (which isn't a bad thing, I just need to cut open the tube in order to weld them in place).

[Maths reference, with a 734mm long bar, 20 degrees needs 251mm from base to base, 25 degrees is 310mm and 30 degrees is 367mm]. 

In fact, just thinking about that step... I could take the plates back off, weld the nuts to the bottom of the plate (the same as it's done for the normal suspension top), then just cut an appropriate hole in the bar. That would mean the nut is in place but the bar itself doesn't have a big gaping hole in it. Thankfully I've only tacked the plated in place at this stage, it won't take much to cut the tacks and start again. I just need to drill the holes first to make sure it lines back up when I'm done. That's this evenings job I think. 

For tube lengths, I've got each strut at 800, the cross bar at 1000, then whatever is needed for the hoop. 

In other news, I got the captive nuts welded in for the seat bases, and the matching holes drilled in the wood. It looks like the bolts screw through far enough to come up flush with the wood, so that should mean I won't feel the bolts through the seat. I'm still worried about the movement on the drivers seat though, it seems to bind very easily. Still, given that it won't be moving very often I am hoping it's ok as is. 

Final roll bar design

 Well, I think I finally have a good solution. As per my previous post, I will be able to go backwards for the support bars. With the fuel tank in place, I was able to measure where the corners ended up, and how I could brace them. This picture shows the angle of the first support in relation to the swirl pot;

Coming straight up from the bottom joint gives clearance up to the corner of the fuel tank. For the horizontal support I have plenty of options;

I'm tempted to come off the open tube as that needs sealing up anyway. With those two as the triangle to support the tank, I can then add a bar straight across for the tank to sit on.

That bar will then become the support for the roll bar;

So the fuel tank will be sitting between the roll bar supports, and the roll bar itself will be braced against the suspension brackets on the diff cage (which is probably the strongest part of the car at the moment!!).

to check the angle I took a picture of the side view;

That angle is 35 degrees, and considering MSUK yearbook says 30 degrees minimum I'm happy with that. 

So this weekend I'm going to weld up a platform for the tank. However, I've just realised the support structure for the rear of the chassis also needs to be included. I'll have to look at that and see if they can both be added at the same time. If not it's just an extra task a bit later on. 

Change of plan for the roll bar

 Once again locostbuilders to the rescue. I posted my pictures for the roll bar design and the feedback was, erm, not good. Some of the points were similar to what I was thinking, others I'd not really thought about.

MrWhippy was the most succinct in feedback;

1. Angle is far too steep. I wasn't sure about this, but it wasn't a good sign that 'the tube bender' only cuts roll bar fish mouths for up to 45 degrees. At what angle does a triangle no longer become a triangle? This MX5 roll bar is a perfect example;

Are those 'support bars' actually supporting? 

2. The brace is not mounted to a strong part of the chassis. This one I wasn't sure about, I think it was the picture angle. The brace comes down to the triangulation point of the chassis, as well as very close to the lateral support for the seats. That's five lengths of 25mm steel converging at one point. As long as I got the fixing right (welded 5mm plate for example) that would be more than enough. 

3. The brace is only supporting half the height of the hoop. Yep, very accurate. I'm introducing forces to the edge of a triangle rather than the corner. It needs to be brought all the way to the top. That would mean a tighter angle on the side bar though.

After a few back and forth discussions (thank you Russbost, Mr Whippy, adampage and adithorp) it is clear that whatever I do on the side I'll just be swapping one compromise for another. I wouldn't actually get the structure required to keep my head off the floor with the car upside down. 

adampage had an interesting idea though. Why not bring it down to the diff cage? Initially it was a no-go, that's where I have my fuel tank;

But as I looked at those photos I realised that I still need to build out a platform for the fuel tank. That strap is currently the only thing holding the tank on to about two inches of metal! Since I have to support the fuel tank already, why not simply build it out to either side to make platforms for rear braces. They could be triangulated to the diff cage (which is a substantial cube already) and I wouldn't lose any boot space because of it. 

The only thing I'd need to consider is getting the bars through the bodywork. I'd need to make sure that at least one end of the roll bar is as thin as it can get. There's a couple of options, both appear on this roll bar;

The first option is a sleeve with bolts through, the example can be seen top left and right and is a 'double bolt' arrangement. That would require finding some tube that fitted tightly inside the roll bar tube.

The second option is a double shear bracket with a bolt through, which is what is used on the diagonals in the image. I prefer that one to be honest. Demon Tweeks sell the OMP gudgeon pin and weldable roll bar connection, but I could also use steel plate. 

Hmm, looks like Race Spec Cages (AKA Ebat Tube Bender) have the sleeve option; https://www.ebay.co.uk/itm/331096168053. I'm not sure it would work though, to keep things tight the bar would not have any 'wiggle room' which would make it difficult to fit. 

Anyhow, first thing is back to the prototype stage to build out the platform and see if the rear stays would work around the fuel tank. 

Edit: A quick note on angles. Looking at the MSUK yearbook I can see that a minimum angle of 30 degrees is required. At least that gives me something to work to. It also gives some guidance on bracket types and there's a few options. I'm assuming if they're MSUK approved then they're good enough for me. Images K21 to K30 show the various brackets, starting on page 200 of the rule book. 

Seat belts

 When I was putting the seats in, my attention came back to the seat belts, in particular the buckles. The Mark 1 are on a large stalk and wouldn't be suitable. I bought some mark 2 buckles off Ebay, I had 'lost' them but managed to find them in my tool box.

Unfortunately while they are shorted than the mark 1, they're actually so short that they interfere with the seat! So they're not suitable. Back to the mark 1 buckles.

I did notice that the buckle was covered in a hard plastic with a metal support bar. I realised that if I remove the plastic and the bar it becomes a regular buckle. This picture shows what I'm working with;

The far right is the mark 2 belt, originally it looks like a good idea but turns out it's not. The far left is the original mark 1 with a plastic shell keeping it stiff. The centre is the one I'm going to use, it has a suitable length of webbing so that it doesn't interfere with the seat, but it also means that it's floppy enough to work as a seat belt. The buckle should sit roughly at the hip depending on where the seat is positioned. 

So that means at the end of the weekend I have;

1. Seats on working seat rails.

2. A roll bar ready to be measured and ordered.

3. Seat belts ready to be bolted in place (although the top seat mounting needs the roll bar). 

There's a few details to be finished up, then I can get the foam and cover on to the seats. 

Next big job, engine fit and propshaft measure.

Seat mounting rails

 Another job finished up this weekend was the chassis mounting rails. This was a pain because it wasn't until I tried to fit the drivers door that I realised they're not matching! The passenger seat went in ok, and it works;

I put the aluminium panels in just to make sure it all moved correctly without binding. It does go back far enough to touch the seat belt reel but it doesn't stop the mechanism from working. I could also put a stop on the rail if needed. 

The drivers side went in and I immediately realised there wasn't enough tension on the seat rail wire. Only one side would release. So I had to reposition the drivers side rail, but eventually I got them both fixed in place;

The seat bases need to be fixed in place, and the nuts need to be welded in place. Once I have the foam and covers on I'll only be able to get to one side, so I need to weld those nuts on. To bolt the seats to the car I have access top and bottom so don't need to weld them in place. 

This did present a problem though, there is very little clearance on either side. The seat belt locks won't fit...