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Windscreen tenax pegs


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Hi

I know this subject has been covered a number of times however none seem to cover my issue.

A previous owner had replaced the windscreen tenax pegs with snap domes which are riveted in place. I had to replace a couple when I rebuilt the car some years ago. At that stage I had noticed that some of the threads had been drilled out.

I would like to now replace the domes with the correct pegs however I suspect that the threads are too damaged to re-tap ( and hole too big).

Question - I see that The Roadster Factory has pegs item number 553837 which are designed for the aluminium frame and go right through the windscreen. Has anyone used these on a steel frame. Albert from TRF has heard of people using them but has no experience himself. 

I am wondering if this would be a good solution to my problem.

Regards

Brian

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IMHO

Given that these pass through the alloy screen I doubt that you could do that without removing glazing panel due to risk to glass. Normally you have to be sure that the threads for correct pegs are shortened to avoid bottoming out on the glass and shattering it. Apart from that it would look nasty. The tolerance between the glass edge and the pin thread is very close and the frame is not that thick to allow helicoil type hole size reduction to suit Tenax pegs.

I suggest that you have two options:

Remove glass,

Repair holes by brazing holes.

Re-drill very accurately and tap threads

Re-chrome.

Replace glass.

or

Look for a good replacement screen frame fit and forget.

If the "snap domes" are riveted then surely you have the rivet holes to sort as well?

Rgds

Rod

 

 

Edited by Rodbr
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Hi Tony ,

I presume that as you don't say you mean fit the alloy screen fittings?

I would like to see that as well not that I would consider it as an option.

I am intrigued to know how you avoided hitting the screen, please give us a blow by blow how you did that as I like many i am sure would appreciate your fix!

I presume there was some delicate work.

How  do you avoid the chance of the frame pulling off the screen when the hood contracts in cold weather which it will do under normal circumstances?

Rod

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Hi Tony

Yes photos and any info would be good. I too am not to bothered about originality as I want a driver car.

Rod screens over here are like hens teeth so finding a replacement would be almost impossible - to fill and drill would be expensive too

Regards

Brian

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Hi Brian,

Look closely at the threads, are they smooth or just stripped?

You could possibly try this as a solution.

Glue the pegs in the worn holes with a plug of JB Weld or similar. I am sure that strength wise it would work but the lateral load if the hood is very tight it might not! A cheap and easily reversible workaround and got to be worth a try.

Roger,

Not sure what you mean about the large caps looking "iffy" could you expand as I recognise the issue of originality in connection with the differences between Baby tenax and the later slightly larger type I am not sure what is Iffy?

I used the modern Tenax fasteners on my 3a below as supplied through Woolies.

Furthermore I have recently bought some of the "modern" pegs with a view to reworking them to suit the Baby Tenax females and in all dimensions other than ball shape and diameter the look identical to the originals. ( without a magnifying glass and micrometer.) Now reworked and they will pass all but closest scrutiny as being close to the original size and shape.

P5300095.thumb.JPG.74ed9f9ec9d2b49a73e1ff94fea7b9ae.JPG

best regards

rod.

Edited by Rodbr
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Hi Rod,

            I do not have a TR2/3/3A. I have been told that the small tenax look good on the windscreen frame but the bigger ones do not.

This is what has been told to me and I am passing it on.

 

Roger

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  • 1 month later...

Hi All

I have managed to drill out the rivets with the screen in situ (and without cracking). About 4 of the holes have thread visible and may just need retaping. The others I will need to plug up with JB Weld or similar as Rod suggests. I contacted Loctite as I had seen in a previous thread that they produced a thread repair kit. Unfortunately they do not bring into New Zealand any longer. They have suggested plugging the hole with Epoxy Weld, spraying the peg with silicone and inserting in the Epoxy and let set. Basically the same a Thread repair.

Can anyone advise what the tap thread /tap I need to use to spruce up the "good" threads - ba x 3/16" seems to ring a bell. Or is there something similar

Cheers 

Brian

Edited by brian-nz
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  • 3 weeks later...

Glad to see you are making “proper” use of the office.

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Hi Brian,

Looks well but i doubt your screen will fit well if at all.

If the frame will part company with normal fitting I.e short Tenax fasteners when under tension from the hood as it cools. You wont get the "bite" from the screen rubber to hold it well.

I would do a trial fit up without screen rubber but It appears from your pics that the screen will foul the screw shafts and not close up at the corner joints. Your still have to fit the rubber in as well! If you don't trial fit you may well crack the screen trying to close it together at the corners with the rubber in place.

With the shortened Tenax pins it ain't easy and requires six hands and numerous clamps and Spanish windlasses. The rubber distance pieces to centralize the screen also make for fun.

As all have said Good luck with it!!!!!

Personally I would have gone with the glued in Tenax pins as it will be more forgiving and still reversible. I shouldn't think there are many screens in New Zealand!

Rod

Edited by Rodbr
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Ally screen frames are slightly larger to get over this problem.

Stuart.

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I think what Bob says will be the only way to do it.

DO make sure you wear eye protection and a GOOD face mask.

You may need to do it with a constant flow of water over the cutting area to keep things cool. I would guess even a small amount of local heat could cause a crack to run out from where you are cutting it . If that does happen, it’s bound to be on the very last cut, when all the rest have worked perfectly.

 

Charlie.

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My idea, from many many moons ago (and I never completed the project)
was to line the frame with a rubber packing to ensure the glass could 
never hit the tenax fixings. (I had an aluminium frame).

If you fit a correct thickness strip around the glass, you will probably end up
hammering the glass/frame together (obviously a rubber hammer or using
a wood block).

I would have fitted the rubber packing also in the bottom part of the frame
to prevent the glass slipping down over time and allowing rain to blow into
the car over the top of the glass when driving at speed.

AlanR

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3 hours ago, John Morrison said:

Looks super Brian, if you've got this far,

sure fitting the glass won't beat you,

John.

Agree John!

... Don’t ever underestimate our ‘Kiwi cousins’, they are tenacious resilient and great ‘can do’ mechanical engineers..... I used to rally against Alisdair Caldwell - he came over from NZ and got a job sweeping the floor (so he tells it) and became head mechanic at McLaren in the glory days.... Tough, tough competitor who could fix anything, from the mundane to the exotica, on the side of the road using only his initiative...

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Thanks guys for your comments.

Initially I had tried to glue in the pegs and used JB Weld but this did not work when under some pressure. Next thought as previously suggested was to braze holes and rechrome but this is a very expensive excerise over here.

I have decided to replace the existing  toughened glass screen with a laminated one. The old one is quite scratched and pitted. I have also decided to get a professional to put the glass in (its being done under insurance). When I restored the car about 5 years ago the windscreen person had trouble with the rubber and in the end used sealant. Has worked since then with no problems.

The pegs shouldn't be an issue as I could feel where the glass was through the holes before I decided to remove the screen. The screen came out of the channel so in theory should go back in.

Us Kiwis have an old saying -Anything can be fixed using a piece of number 8 wire (used for farm fences) so I am sure this issue can be overcome

Cheers

Brian

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can we presume that since you refer to brazing the holes it is a brass/ chromed frame not Ally.?

I had a think about this and given the possibility of the screen cracking after being fitted by a "pro" with sealant. 

How about trying the following :

take the tenax fastener and cut a cross like a Dum Dum bullet 1-1.5 mm deep, install and then through the hole for your present fitting spread the cross with a punch and suitable die. Similar to old style ship rivets, relaying in this case on the spread to lock in place. Glue the cut of screw end into the hole. This will leave you with the gap for the screen to move and flex without any risk to contact the screen.

Don't discount what they call "brush on Chrome plate" Check out Gateros plating website. Might be OK to patch in defects.

https://www.gaterosplating.co.uk/plating-kits/brass-brush-plating-kit

Finally i would lay the new screen over the old one to confirm the exact size is the same.

Rod

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