[Shop-talk] How to open clearance on a hardened pin?

Sun Mar 24 07:58:07 MDT 2024

The right side pin fits into both bearings so it isn't the bearing races, the problem is the left pin. 

It came out "easily" because it's a fine threaded pin and the bearing race had the swingarm face to rest against during unthreading and mask any issue. Very much like removng a nail with a claw hammer- there's the wood surface to lever against. 

Going in there is nothing to brace the race against because of the clearance behind it. 

I could clamp the swingarm sides together but I'd still have a ton of stiction on that pin, which I can't have if I'm going to set the clearances. 

I can't remember if the list accepts pictures but here is the setup. What's the most baffling is both pins measure 0.5900" around the entire circumference at the trouble point. Right pin still has anti-sieze on it. The friend with the lathe might have some crocus cloth, I'll try that tonight. 

jim

> On Mar 24, 2024, at 9:17 AM, old dirtbeard <dirtbeard at gmail.com> wrote:
> 
> I had a '73 MG V7 Sport which had a different swing arm but a similar arrangement.
> 
> I would think that if they came out easily, they should go back in reasonably easily. If not, something is interfering with the refitment.  
> 
> Perhaps:
> inspect the fitment for any scoring or swarth that could be interfering (I am certain that you already did this)
> Swap the left bearing for the right to see if there are dimensional differences.
> Swap the bearing side you insert first into the arm 
> As mentioned, use a light abrasion like crocus cloth or scotch bright pads to polish up the surfaces of the bearing and the swingarm cylinders
> I know that it is little help, but if they came out without hammering, they should go back without hammering. Something has changed that is causing the interference fitment now and you will need to determine what has happened/changed during the R&R process.
> 
> best,
> 
> doug
> 
> On Sun, Mar 24, 2024 at 3:57 AM Al Fuller <alfuller194 at gmail.com <mailto:alfuller194 at gmail.com>> wrote:
>> Well, ok then... BTW, are the bearings and races not in the diagram you referenced or am I missing something?
>> 
>> ________________
>> Best Regards,
>> Al Fuller
>> 
>> On Sat, Mar 23, 2024, 11:23 PM Jim Franklin <jamesf at groupwbench.org <mailto:jamesf at groupwbench.org>> wrote:
>>> Good thought but I should have specified that I tried inserting the pin directly into the bearing race and it exhibited the same issue. 
>>> 
>>> jim
>>> 
>>>> On Mar 23, 2024, at 10:14 PM, Al Fuller <alfuller194 at gmail.com <mailto:alfuller194 at gmail.com>> wrote:
>>>> 
>>>> Jim, I don't know this part/assembly but it seems to me that the original engineering would not have required hammering. Added to that one side goes in well but not the other, I'm wondering if the bike might have a little eccentricity in the fit-up? Is it possible that it was laid down at some point in the past and has a little twist in the assembly?
>>>> 
>>>> ________________
>>>> Best Regards,
>>>> Al Fuller
>>>> 
>>>> On Sat, Mar 23, 2024, 10:17 PM Jim Franklin <jamesf at groupwbench.org <mailto:jamesf at groupwbench.org>> wrote:
>>>>> I'm assembling a Moto Guzzi swingarm which attaches to the back of the gearbox. The gearbox has 2 recesses in which live plain roller bearings. The swingarm has threaded holes through which locating pins screw. The tips of the pins are unthreaded and locate into the ID of of the roller bearings. Parts #12 here:
>>>>> 
>>>>> https://harpermoto.com/collections/1980-1984-v-50-iii-500-swing-arm
>>>>> 
>>>>> The pins are known for being stuck yet mine came out easily, probably because the inner race was able to rest against the swingarm while the pin was being pulled out. Assembly is another matter. The bearings don't bottom out in their recess so the inner race has nothing supporting it when I screw the pins into the swingarm, and one pin is not sliding into the inner race (the other pin fits into both races as it should). I don't want to hammer on it and dent the races. I've sanded it with some 400 grit but I'm pretty sure the pins are hardened and so I haven't made any progress.
>>>>> 
>>>>> Any thoughts on how to get this pin to fit in the bearing? Freezing it is not a great option because of the time it takes to get things installed, plus I'll need to do clearance adjustments. 
>>>>> 
>>>>> thanks,
>>>>> jim
>>>>> _______________________________________________
>>>>> 
>>>>> Shop-talk at autox.team.net <mailto:Shop-talk at autox.team.net>
>>>>> Donate: http://www.team.net/donate.html
>>>>> Suggested annual donation  $12.96
>>>>> Archive: http://www.team.net/pipermail/shop-talk http://autox.team.net/archive
>>>>> 
>>>>> Unsubscribe/Manage: http://autox.team.net/mailman/options/shop-talk/alfuller194@gmail.com
>>>>> 
>>> 
>> _______________________________________________
>> 
>> Shop-talk at autox.team.net <mailto:Shop-talk at autox.team.net>
>> Donate: http://www.team.net/donate.html
>> Suggested annual donation  $12.96
>> Archive: http://www.team.net/pipermail/shop-talk http://autox.team.net/archive
>> 
>> Unsubscribe/Manage: http://autox.team.net/mailman/options/shop-talk/dirtbeard@gmail.com
>> 

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/shop-talk/attachments/20240324/fc2fe3fb/attachment-0001.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMG_7679.jpeg
Type: image/jpeg
Size: 214048 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/shop-talk/attachments/20240324/fc2fe3fb/attachment-0002.jpeg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMG_7680.jpeg
Type: image/jpeg
Size: 188431 bytes
Desc: not available
URL: <http://autox.team.net/pipermail/shop-talk/attachments/20240324/fc2fe3fb/attachment-0003.jpeg>