330GT 2+2 Door Checkstrap Questions????

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Darren C
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330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Sat Oct 26, 2013 1:28 pm

Today I started work on some check straps I got off ebay for £3

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The straps have obviously had a hard life with a really badly welded end on one and a cracked end on the other where the metal just fell off when I tried to clean it up with a wire brush.

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Both failures are where the pin holds it into the body by the door hinges.
Since I have no other straps and little money, my only option is to repair/remake them.
However I have a question……..

The shape of both arms is different, one is slightly more curved than the other?
I suspect that the curved one is correct and the slightly straighter one has got that way through a hard life of being tugged as the door flies open, or its off the drivers door where its had far more use.

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Is this right?
Can someone take a look at theirs and let me know the correct shape please, before I make new ones.

I have started by drilling out the spot weld and cleaning up one arm to see how the radius restraining lump has been added. It looks to be brazed on. I had to cut the end off with a hacksaw to separate the parts, but now know how its made so can easily make a new pair.


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The interesting thing is that when drilling out the spot weld and hacksawing it; I discovered it really is VERY poor grade steel and very soft, so its no wonder the pins pull out the ends and the arms bend easy!
330GT 2+2 4HL 6727
Small things make perfection, but perfection is no small thing.

Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Sun Oct 27, 2013 2:42 pm

This afternoon I got some 3mm stainless steel plate I had left over from making some other brackets and roughed out two new check strap arms with my hacksaw. (I opted for the more curved shape)

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After a couple of hours filing and drilling, the finished shape was gained.

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After cleaning up the two old ends of the ebay damaged checkstraps that I’d drilled the spot welds from previously; I then welded them onto the two new arms I’d made.

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Now for the hard bit.

The original check straps have two semi circular bulges to act as restraints just before the door is wide open. After filing these off an old arm to see how they were made I found that the arm was originally pressed on one side and then an insert brazed into the other.
I got 3 sections of 5mm plate off cut and made a perfect profile semi circle that fitted the remaining original arm section. This was used on the centre plate and the two outside plates I left flat. The sandwich of 3 plates was welded together and then the surface filed flat and smooth to leave a perfect indentation (concave) so that I could stamp the new arms. I then made a short convex stamp out of some more scrap plate and had the perfect tools to make the correct profile. I cut and marked the sandwich section so that when the new arm sat on it, the bulge would be in the correct place.
I then gently heated the new arms to cherry red with my plumbers canister blow torch and stamped the new arms.
The stamp concave and convex is shown below along with the old checkstraps showing the same orientation as new. If you look carefully you can just see the remains of the old braze (gold colour) in the Left hand old checkstrap.

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I ran out of time today, but tomorrow I’ll make the small insert bulges for the reverse of the stamped one and braze them in.
330GT 2+2 4HL 6727
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John Vardanian
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by John Vardanian » Sun Oct 27, 2013 11:58 pm

I am speechless, Darren, great work!

john
PF Coupe

Michael Bayer
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Michael Bayer » Mon Oct 28, 2013 9:11 am

Darren Great work!! Are you going to make a few for sale to guys here? Lowell I will chek my pins when I am back in Georgetown tomorrow, M
Michael J. Bayer
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Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Mon Oct 28, 2013 12:59 pm

Thanks John.

Michael, I wish I had time to make more... the two straps have taken about 12 hours so far and I' ve still got to make the inserts and braze them in!

The pins are easy, Turning them on my lathe will take minutes, so I don't mind doing some spare ones for anyone without a lathe. The Check straps are made using just a hacksaw and file, so hopefully it will inspire others to have a go themselves, it really is school boy metalshop stuff.
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Tom Wilson
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Tom Wilson » Mon Oct 28, 2013 4:59 pm

Darren C wrote:... it really is school boy metalshop stuff.
None of my metalshop stuff turned out that nice! Keep posting as your work is terrific!
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Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Mon Oct 28, 2013 5:41 pm

Tonight I made the two raised semi-circular lumps that go on the opposite side of the pressed lump from a small piece of left over off cut stainless.

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Once I filed the correct radius, I cut it into two 6.5mm sections and filed a slot on the rear to engage with the pressed concave part of the arm. The hardest bit was holding on to the tiny things as they are only 1.5mm high!
Picture below shows each side of the items.

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I got some silver/braze rods left over from other jobs at a local engineering shop, they throw them out at 2” long as they get their fingers burnt from being too near the flame at 2” long, so I collect them free of charge. Just hold them in my long nose mole grip pliers and I can use all the 2” rod!
After a bit of a fiddle setting things up I brazed on the two lumps.

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I ran out of time again so tomorrow I shall do the final clean up and remove the flux and any excess braze to finish the check straps completely.
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Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Mon Oct 28, 2013 5:48 pm

Tom Wilson wrote:
None of my metalshop stuff turned out that nice!
:lol:

Brilliant Tom, you did make me chuckle.

I was making stuff far more complex than these age 11 years, by age 15 I made my own lathe powered by a drill. I made the bed, headstock and saddle in woodwork class, sand cast it in aluminium, milled, drilled and machined it, so I had a minature lathe about 2 feet long to make model steam engines on. That was over 30 years ago so I've moved on from that "Schoolboy lathe making stage"

Dont tell me Tom, you made an ashtray at school?
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Tom Wilson
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Tom Wilson » Mon Oct 28, 2013 6:07 pm

Darren C wrote:Dont tell me Tom, you made an ashtray at school?
It was ugly, but really strong!
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Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Mon Oct 28, 2013 6:58 pm

Sounds like my ex-wife
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Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Tue Oct 29, 2013 4:43 pm

Today I finished cleaning of the flux and tidying up the silver brazed restraint lumps.
I then spent a couple of hours fine wet & drying the new arms to a mirror finish. The originals are mild steel with bright zinc plate (BZP), so they do rust as shown at the beginning of this thread. My new ones are Stainless so there’s no plating to rub through on the moving parts. However I did re-use the circular ends so I treated them to some silver zinc paint where I’d drilled and spot welded.

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They are shown above with the “pressed” lump upper most. In comparison below where after cleaning up the old rubber bushes and fittings you can see my brazed in lumps upper most.

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All in all I’m very pleased with the repair of the check straps, so they’ll now get bubble wrapped and put in my store of parts awaiting the grand assembly.

Any news on the pin details so I can make a few of those guys?
330GT 2+2 4HL 6727
Small things make perfection, but perfection is no small thing.

Michael Bayer
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Michael Bayer » Mon Nov 04, 2013 11:35 am

Darren/Lowell I sent you pics of my hinges that are attached w bolts My car is pretty original BUT the bottom of the bolt just clips the body which I never saw until I took the second pic taken from below Thus I am of the mind there should be pins NOT bolts there and would MUCH appreciate a pair of pins if there are any available from this effort M
Michael J. Bayer
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tim
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by tim » Mon Nov 04, 2013 4:02 pm

Greetings... As I posted before, mine has a bolt and nut and like yours, it just clears the body panel. It has been this way for the 37 years I've had the car so I'm pretty sure that's what it came with.
Tim
1964 330GT 5769 -the big yellow taxi 61&66 Morgan +4's Daimler SP250 and some other dull stuff plus a brand new Mini Cooper S Clubman JCWS

Darren C
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Darren C » Tue Nov 05, 2013 5:26 pm

Michael Bayer wrote:Darren/Lowell I sent you pics of my hinges that are attached w bolts
Hi Michael, I've not received any pictures or pm's?
330GT 2+2 4HL 6727
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Re: 330GT 2+2 Door Checkstrap Questions????

Post by Michael Bayer » Wed Nov 06, 2013 10:02 am

Darren Please e mail your address to me mbayer@erols.com will send pics I dont know how to post them directly on this site Perhaps you can post hem here for the gang
Michael J. Bayer
330GT s/n 9727
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