allan screws

Post Reply
johnbirchjar
moderator
Posts: 1245
Joined: Sat Mar 07, 2009 11:20 pm

allan screws

Post by johnbirchjar » Mon Oct 03, 2016 11:44 pm

Hi guys' any tips on how to undo the allan screws on the face plate for the clutch cushdrive rubbers?I think the ones on the Classic have been "Locktighted" evil I have tried warming them with a blow lamp,but the allan screws are a bit fragile (3mm allan key)and I am rather reluctant to use to much force as one of them has allready started to "ring round" cry .I purchased a 3mm "bit"today in the hope that a bit more steady leaverage using a tommy bar may be a better bet than an allan key wink,other sugestions will be most welcome,rgds,J.B.

Dell Boy
moderator
Posts: 432
Joined: Mon May 25, 2009 10:46 pm

Re: allan screws

Post by Dell Boy » Wed Oct 05, 2016 8:31 pm

Use a three foot bar & put very gentle pressure on it at the same time clouting the bit with a club hammer to jar the allen screw as well as driving the bit into it. Only very gentle pressure & good rythmic continual wacks with the hammer. You will need a long bar. With a short one you will sheer the bolt off. You still might but this method always works for me when unsiezing a bolt.Derek.

wust588
moderator
Posts: 82
Joined: Wed Aug 06, 2008 4:56 pm

Re: allan screws

Post by wust588 » Thu Oct 06, 2016 11:32 pm

John, I presume you mean the countersunk screws removed with a 3mm key.Give them a tap first with a brass drift and hammer after some heat, then using a centre punch, as far from the centre of each screw as possible, "drift" the screws anticlockwise. That's how I usually get them out.

johnbirchjar
moderator
Posts: 1245
Joined: Sat Mar 07, 2009 11:20 pm

Re: allan screws

Post by johnbirchjar » Tue Oct 11, 2016 12:04 am

I don't think a three ft bar on a 3mm allan screw is advisable,a tad ott me thinks wink.Three of the wee buggers I have managed to undo with heat and aplying gentle preasure using a ring spanner on an allan key stud,while gently tapping with a "soft" hammer,I then tried the centre punch option but that didn't work either!!,and two of them have "rung off" evil,I have now drilled the heads(almost) off the remaining two and hope to tap the cush drive face plate from the other side once all the clutch housing is off the g/box main shaft,and therin lies a problem,Nortons(in their infinate wisdom)decided to put a 5/8(19mm) nut on the end of said shaft that is only acsessable through a hole in the Cush Drive Face Plate that isn't large enough for a normal diametre socket to pass through cry,hence the grief having to get the Face Plate off!! but all is not lost,I have a biker buddy who has a lathe and has offered to skim down a socket for me smiley,J.B.

Dell Boy
moderator
Posts: 432
Joined: Mon May 25, 2009 10:46 pm

Re: allan screws

Post by Dell Boy » Tue Oct 11, 2016 8:42 pm

You would be surprised John how effective gentle pressure applied through a lot of torque (3 foot bar) is in breaking free seized nuts/bolts if incorperated with shocking the screw at the same time.Derek.

Wayne
moderator
Posts: 550
Joined: Tue Jul 14, 2009 10:25 pm

Re: allan screws

Post by Wayne » Tue Oct 11, 2016 9:35 pm

Hi AllI found heating the head of the screw then allow to cool, this breaks the locktight, then reheat the screw I then use a quality hand impact wrench. you cant do this with a blow torch though as you heat the whole area not just the screw head.I have two race clutches and the mod they did was brilliant, the plate has a grove so you can grind a slot for a heavy flat blade in the screw. on reinsertion the heads of the screw are centre popped and flair into the grove locking them in position. Regards Wayne

johnbirchjar
moderator
Posts: 1245
Joined: Sat Mar 07, 2009 11:20 pm

Re: allan screws

Post by johnbirchjar » Tue Oct 11, 2016 11:48 pm

Yipee Very Happy,I have managed to undo the 19mm nut using a long reach socket which was slim enough to go through the hole in the face plate(the nut was done up well tight though,the use of a "rattle gun"+ a 2ft long scafold tube+gentle thumps with a rubber hammer before the b*****d would come undone) ,the whole clutch/starter assembly is now off the shaft and guess what?I still can't get to the b****y cush drive face plate evil, so it's "back to the drawing board" to figure a way to get the last two (now almost headless)allan screws undone,or do I just drill off the last of the heads and hope I don't damage the face plate beyond repair in the process cry(I suppose I could allways buy another one wink)J.B.

wust588
moderator
Posts: 82
Joined: Wed Aug 06, 2008 4:56 pm

Re: allan screws

Post by wust588 » Mon Oct 24, 2016 10:42 pm

A tricky one that John!It might be worth asking Andover Norton the cost of a replacement?What is the condition of the clutch plate grooves? If worn badly, a new one would be a good option.Other than that, do you have a friendly machine shop locally who would remove the remains of the screws?If you can drill the screws dead on centre, an easy out might work. Get em stinking hot when you try the easy out.ATB,John.PS, Like you, I've stripped an assembly in the past and found sod all wrong with the rubbers. Then it's a happy timeputting in new ones!Did you make a note, by the way, which way the rubbers were situated when the plate came off?

johnbirchjar
moderator
Posts: 1245
Joined: Sat Mar 07, 2009 11:20 pm

Re: allan screws

Post by johnbirchjar » Tue Oct 25, 2016 11:55 pm

What I did when examining the rubbers was take one out examine put it back the same way and so on, so I thought with replacements was old one out,new one in,but I suspect this is not as easy as it sounds wink.Fortunatly the face plate is hardly damaged at all Very Happy,and the "alan screw stubs"I will carefully grind down to the face and (hopefully)get a biker buddy of mine who has a well equiped workshop to get busy with drills and easyout,I will report anon,rgds,J.B.

wust588
moderator
Posts: 82
Joined: Wed Aug 06, 2008 4:56 pm

Re: allan screws

Post by wust588 » Wed Oct 26, 2016 10:44 pm

You are right John, putting in new rubbers is far from straightforward.......It's a bit "quart into a pint pot" type of job where the new rubbers seem to be a lot bigger than the old ones.The first one will go in easy and so will the next one. It is fitting the third rubber that is a challenge.To stand any chance of accomplishing this, you need some sort of holding fixture. The inner splined section needs to be prevented from rotating by mounting on an old mainshaft and fixed in a vice.The hub then needs to be rotated to open up the gaps to fit the rubbers, to stand any chance of fitting the last one.The factory service tools consisted of an old bronze clutch plate brazed to a long bar.

johnbirchjar
moderator
Posts: 1245
Joined: Sat Mar 07, 2009 11:20 pm

Re: allan screws

Post by johnbirchjar » Wed Oct 26, 2016 11:18 pm

The gearbox is Triumph,but the clutch is Norton,so who's is the mainshaft?J.B.

wust588
moderator
Posts: 82
Joined: Wed Aug 06, 2008 4:56 pm

Re: allan screws

Post by wust588 » Sat Oct 29, 2016 10:44 pm

You are right that the gear cluster was originally Triumph, though I'm not sure if the Norton type clutch was used by Triumph.To my knowledge, Norton used at least four different mainshafts. All had the same clutch.That's discounting the F1 of course.

Post Reply