Skip to main content
000000 000001 000002 000003 000004 000005 000006 000007 000008 000009 000010 000011 000012 000013 000014 000015 000016 000017 000018 000019 000020 000021 000022 000023 000024 000025 000026 000027 000028 000029 000030 000031 000032 000033 000034 000035 000036 000037 000038 000039 000040 000041 000042 000043 000044 000045 000046 000047 000048 000049 000050 000051 000052 000053 000054 000055 000056 000057 000058 000059 000060 000061 000062 000063 000064 000065 000066 000067 000068 000069 000070 000071 000072 000075 000078 000081 000084 000087 000090 000093 000096 000099 000102 000105 000108 000111 000114 000117 000120 000123 000126 000129 000132 000135 000138 000141 000144 000147 000150 000153 000156 000159 000162 000165 000168 000171 000174 000177 000180 000183 000186 000189 000192 000195 000198 000201 000204 000207 000210 000213 000216 000219 000222 000225 000228 000231 000234 000237 000240 000243 000246 000249 000252 000255 000258 000261 000264 000267 000270 000273 000276 000279 000282 000285 000288 000291 000294 000297 000300 000303 000306 000309 000312 000318 000321 000324 000327 000330 000333 000336 000339 000342 000345 000348 000351 000354 000357 000360 000363 000366 000369 000372 000375 000378 000381 000384 000387 000390 000393 000396 000399 000402 000405 000408 000411 000414 000417 000420 000423 000426 000429 000432 000435 000438 000441 000444 000447 000450 000453 000456 000459 000462 000465 000468 000471 000474 000477 000480 000483 000486 000489 000492 000495 000498 000501 000504 000507 000510 000513 000516 000519 000522 000525 000528 000531 000534 000537 000540 000543 000546 000549 000552 000555 000558 000561 000564 000567 000570 000573 000576 000579 000582 000585 000588 000591 000594 000597 000600 000603 000606 000609 000612 000615 000618 000621 000624 000627 000630 000633 000636 000639 000642 000645 000648 000651 000654 000657 000660 000663 000666 000669 000672 000675 000678 000681 000684 000687 000690 000693 000696 000699 000702 000705 000708 000711 000714 000717 000720 000723 000726 000729 000732 000735 000738 000741 000744 000747 000750 000753 000756 000759 000762 000765 000768 000771 000774 000777 000780 000783 000786 000789 000792 000795 000798 000801 000804 000807 000810 000813 000816 000819 000822 000825 000828 000831 000834 000837 000840 000843 000846 000849 000852 000855 000858 000861 000864 000867 000870 000873 000876 000879 000882 000883 1.slide1 2.slide2 3.slide3 4.slide4 5.slide5
English French German Italian Spanish

Rocker spindle plate screw hole problem

Forums

My daughter bought me a set of stainless oval plates and screws set for Christmas thought i would fit them.  But a previous owner must have stripped about half the holes, tapped them 5/16 BSW, opened the plate holes. Considering my options: Don’t think i can helicoil back to 1/4 from that size. Maybe get stepped studs made, normal studs in good holes and fit 1/4 nuts. Not sure if i can drill deeper and retap to 1/4, don’t really know how deep i can go without running into something.  Any other ideas please, don’t want to remove the head

thanks

 

Permalink

I bought some stainless whit  hex head  set screws  from E bay  to fit the RGM  rocker conversion,   certainly longer than std  1" i think.    They were camera mounts , they may do 5/16 ,I will look.

Permalink

Item 140732849851    2x5 packs (10 bolts) total free post   £14.84     1" long  , but will have the bigger than std Norton hexagon .?     Grind off the lettering .       Use a longer bolt to check out the thread depth ?    If you look around you may do better.  May find some reduced hex  set screws ( Fully threaded bolts)

Permalink

Hello Robert

just took exhaust rocker cover off at 5/16 the bolt would foul the body of the rocker if too long, think i just need to put it back together and live with it for now. If i ever needed to take the head off i think some Timesert inserts would get me to 1/4 UNC which is a close match to whit. Thanks

Permalink

Is this an area where a (1/4 or 5/16 stepped) studs the full length for the hole is needed, clean thread in hole and locktite the stud in and then use hex nuts to hold the plate in place-yes it might look naff but it would work, as you would stop taking the steel bolt in an out of the ally head. (I have always thought the same with bolts holding exhaust clamps in, use studs and let the nuts take the wear not the thread into the alloy)?

Permalink

How often do you remove them? I do have to remove the screws from the rear one if I take the rear main head bolt right out. Anyway..can you not get reduced head size 5/16 screws from someone like Nooky's nuts?

Alan not a silly idea this is exactly what i plan to do cheers

Permalink

If you find someone to make the studs I could do with something similar to mount my new alternator  onto the orriginal  alloy housing.    Bits of tin not ideal.  Did suggest it to my fav Norton stockist but it fell on deaf ears.

Permalink

The first proper production Model 7 engines, built from March 1949, onwards had tapped rocker end  plates with 5/16" holes. These plates were brazed to the rocker spindles to form a combined item. See photo. The plates were held in place by standard 1/4" bolts/pins that self-centred due to the spindles. No need for oval plates with tangs to hold the spindles in position. To extract the rockers 5/16" bolts were inserted in place of the 1/4" bolts and these turned against the mouths of the 1/4" bolt holes.

These single piece spindle/plates were quicky superseded by the two part end plates. It was found that when new, the extraction  procedure went fine but eventuallyburnt oil jammed the spindle in the head and then the plates distorted due to heavy hands. Once bent they were almost imposible to flatten and leaked from then on.

I wonder if Pete's plates are based on these Mk 1/Mk2 engine versions?

Permalink

Maybe you could fill it up the hole with Lumiweld using a Rotherberger torch at about 300C and retap it to 1/4 Whit. 

The 2BA holes in my timing cover for the tacho drive have been retapped to 0BA. I was thinking of trying this to get them back down to 2BA.

Has anybody tried anything similar?

 

Permalink

These two materials do not get on with each other very well. The Lumiweld kit generally contains  both a Stainless brush and spiked rod.

An easy solution to this issue is to use thick copper washers under the 1/4" bolt heads. The slot in the spindle end will help to keep the plate in position. You can purchase a bag of these specifically for this purpose. Many Commando and Dominator owners do this to help stop the coarse bolt threads from leaking.  The A/Norton part number is 06 3129.

Permalink

If you do use nuts on studs as Alan suggests, make sure you will still be able to remove the rear cylinder head bolts...unless you are happy to leave them flapping about next time you take the head off.  If that's OK, why not used domed nuts?

In reply to by peter_brown1

Permalink

Hi Peter,

i don't know what equipment you have or your engineering skills but I would be tempted to check how deep you could re-drill then drill and tap the affected hoes out to 1/8" BSP (0.383" o/d x 0.337" core)

Then I would turn 1/8" BSP plugs in aluminium drilled and tapped 1/4" BSCy, screw and Loctite them in and you are back to standard. With careful manufacture you could have them slightly under the outer face to save dressing off.

I think that I have some spare eliptical plates to replace yours that have been drilled out if you want them. 

Regards

Dick

Hi Phil

I didn't fully understand you comment on Lumiweld and SS. Is it an electrolytic corrosion problem, and does it affect zinc, brass and MS too? I was mostly worried about the lumiweld being too soft

Steve

Permalink

Because the screws (although some are 1/4 and some are 5/16) still tighten ok i am going to live with it for now, plenty of other stuff to get on with. When i do it will probably tap remaining ones 5/16 and use stepped studs with dome nuts. Will take the rockers out so i can get the 5/16 tap right through cheers 

Stainless Steel has properties which work in its favour but unfortunately a few that do not. Add Stainless chunks to a fork leg of a well-used Norton and a few years down the line the reaction between the alloy and SS will have caused all kinds of nasties.

In the world of Lumiweld, the rod material will just not adhere to SS at the normal Lumiweld brazing temperatures. Hence the use of a SS brush and pick to clean alloy parts and surfaces.  When Lumiwelding holes or difficult joints,  SS sheets are recommended as backing supports to limit run--off or sagging of the rod material.

My attempts to use Lumiweld on Zinc and Mazac have generally resulted in meltdown. However, on other mainly alloy parts such as broken cylinder fins, levers, crankcase stripped threads and brake shoes I have enjoyed much better success. See attached.

Permalink

Phil

The brake pedal repair looks impressive!

I am planning to simply fill my oversized timing cover 0BA holes with lumiweld and re-tap to 2BA.

I know it is more lumi(solder) or lumi(braze) than lumi(weld) but that looks like a viable idea. The tacho drive isn't exactly massively stressed.

But I reckon that it could work on rocker spindle endplate retainers too. Unless it is just too soft.

 

Steve

Permalink

.. struggle with filling holes with lumiweld as it depends on scratching the surface with the stainless rod to break though the oxide coating on the alloy. I've tried using the product a few times but never with any great success.

Regarding the original query I'd be going with tapping out to 5/16", enlarging the holes in the plates appropriately and using socket head screws - with a reduced head if necessary.

In reply to by ian_soady

Permalink

Thanks for the input Ian, makes a lot of sense. I guess I could run an M6 tap up and down it a few times to clean off the oxide layer. They are very shallow holes. M6 has the same pitch as 0BA but a deeper thread form as I recall.

I may fool around with an old cover, see what works.

Plan B Alloy allen bolts are available, I could tap my holes out to m8, plug them using bearing-fit loctite, and then drill and tap to 2BA.

 

 

 

 

Permalink

.. that the oxide layer forms on alloy virtually immediately which is why when using lumiweld you have to constantly scratch the surface. I believe (though may be wrong) that's why TIG welding aluminium alloys needs AC rather than DC power supply.

Permalink

Has anybody tried this? ( a product test from Old Bike Mart Magazine)

Is it as easy to use as watching the demonstrators suggests? if you follow the instructions included with each pack; then the process is quite simply within the grasp of anyone who can master soldering (that word again!); ...... As the bond is only formed with aluminium or zinc alloys it can be effectively used to reclaim stripped threads in such materials by drilling out the offending hole and popping in a bolt of the correct thread form; `Lumiweld' run around the bolt then bonds to the aluminium but not the bolt, which can be unscrewed from the hole leaving a new thread behind it: Again, the low working temperature of the operation makes this an attractive alternative to other forms of repair, where a complete strip down might otherwise have to be contemplated.

Permalink

I did a dummy run with Lumiweld. I drilled and tapped an M6 hole (0BA for these purposes) through a gearbox inner. I left it a week to oxidise then I ran a degreased m6 tap in an out a few times applying a bit of lateral pressure in every direction to clean up the walls of the thread, and to remove any oxide.

Then I heated the workpiece up to 400DegC using a Rothenberger torch (which took a lot longer than the videos suggest it might) and I filled the threaded hole up with Lumiweld.

I let it cool, then I drilled it and retapped it to 2BA, and it is just like new after cleaning off any excess weld/solder/braze.

Verdict: Lumiweld can fix oversized holes for low-stress bolts in alloy, like rocker end-plate retainers, especially coarse threads.

Permalink

Steve.......Good news....Brownie badge job.

Oxidisation is the Achiles Heel of using Lumiweld for fixing alloy issues. The kits generally contain a Stainless Steel brush and spike to help with the cleaning process. The brush helps to rub off the oxide that the alloy naturally gains from the atmosphere and any any other oil and crud that might poison the join.

As soon as heat is applied to the alloy surfaces oxidisation of the surface begins to increase which is why the scratching of the area needs to happen to ensure a strong join or fill. A light scratching will usually suffice and help produce an amazingly good end result. 

 

Permalink

Next time I will run the tap in and out using a drill, immediately before applying the Lumiweld. Angling it every which way. But even without that it produced a really good result.

I won't be using it for barrel holding down studs any time soon. But tacho mounting, it's up to the job.

Starting with a clean sheet of paper a smooth hole would be more scratchable, but have a lower surface area. However, I am reluctant to open my holes up further because Lumiweld has a tendency to sink into the hole, and they are shallow threads.

I watched a youtube video where the chap went to some considerable trouble scratching the main component and he gets a great "wetting", but then he wants to just plonk the next part on to it with no serious effort to clean it up (actually he just melts the smaller part by accident anyway). It seems to me if both parts were scratched and wetted with Lumiweld first it might work really well, like tinning components before soldering. Then you will be effectively welding two Lumiweld surfaces together.

I would definitely use it to reclaim 1/4W rocker spindle plate bolt holes if I needed to. 

 

Norton Owners Club Website by White-Hot Design

Privacy Policy