2lbs saving is good
FF: Forks Modified Steering Stem
- Thread starter greg brillus
- Start date
Not yet. It is a different factory that is doing that work and I was in there two day ago and the work was underway. I think that the total number to be done was 28 finally so it will take a while. I have the impression that they hope to finish the work this week so perhaps tomorrow. The chaps who are doing this normally work on solid steel cylinders about three feet diameter and three feet long so my job is almost like micro surgery to them. I will post as soon as I have them.
That is correct but they are machined from solid with only a small hole through them and the 7075 alloy is as strong as mild steel.
A further update. I have now pressed about forty of the new tubes and lower motion blocks together. I was pleased to find that the force required with the 25 tonne press was about the same for the aluminium sets as for the steel ones. I had worried that the ali would move more but it did not. Therefore, I did not see any need for the use of Loctite or any further pining to prevent movement of the two components relative to each other.
Eight of the aluminium lower blocks have gone off for anodising (four clear and four black) and once they are back the rest of the steering heads can be pressed together.
Today I have also collected all the machined out lower links. The chap who did the machining showed me where he had struggled with several of the links to get them to clean up totally so it will not be until I start to press the bearings in that I know whether all of them will be useful.
Finally I have heard from Michi Schartner that he and one of his chums have standard front AVO dampers in stock, new and unused. I have one person on my list who wants one of these so that can be a swap. If there is anyone else out there who needs a standard front damper, to be used with Oilite bushes rather than the ball races then there is one going spare. AVO are not keen on replacing the inners of these dampers to bring them up to the alternative specifications or otherwise that would have been the route chosen.
Eight of the aluminium lower blocks have gone off for anodising (four clear and four black) and once they are back the rest of the steering heads can be pressed together.
Today I have also collected all the machined out lower links. The chap who did the machining showed me where he had struggled with several of the links to get them to clean up totally so it will not be until I start to press the bearings in that I know whether all of them will be useful.
Finally I have heard from Michi Schartner that he and one of his chums have standard front AVO dampers in stock, new and unused. I have one person on my list who wants one of these so that can be a swap. If there is anyone else out there who needs a standard front damper, to be used with Oilite bushes rather than the ball races then there is one going spare. AVO are not keen on replacing the inners of these dampers to bring them up to the alternative specifications or otherwise that would have been the route chosen.
Another Update. This is to let you know where this project is. All the lower blocks are pressed on to the steering stems apart from the ones where the lower motion blocks were sent off for anodising. Those should be back early next week. All the lower links are fitted with bearings and fitted to the lower motion blocks apart from one which has defeated me, more of that later. All the springs have been delivered but I am still waiting for the 23 AVO dampers on order. I did chase them up at the start of this week to see if they could send part of the order down early but they prefer to deal with the whole batch together.
What has taken the time? Remember that the bearings are 32 mm O.D. and we need about one thou nip on that to ensure that the bearings are tight but not nipped up and distorted. One thou less than 32 mm is 31.975 mm which is 1.25885827 inches in old money. That is if there is wear due to the Oilite bushes having turned in the link, rather than on the eccentrics, then five thou wear means there is no interference fit. Well over half of the links worked on had this or more wear and so Loctite had to be resorted to. There was a four day delay while Loctite 638 was delivered. Even worse, several links were so badly worn that Loctite was not a solution and they had to be bored, sleeved and re-machined. There were even two which had previously been over bored and had reduced internal diameter bushes fitted to work on smaller than standard eccentrics. Beautifully done but a pain in the posterior. The one on which I have finally been defeated looked in perfect condition and machined up nicely. However when the bearings were fitted and a 20 mm diameter mandrel put through the bearings it was found that it was out of line by 3/16". It was heated, straightened and yesterday I fitted the third set of bearing, the first two sets having been destroyed. By this morning the whole thing had relaxed again and it was no longer lined up.
So that is where we are now. I should be able to start and send out parts next week to those who have not ordered AVO dampers or are having lower motion blocks anodise.
While this has been going on I have also been designing a set of parts to fit with a Chinese copy of a Hyper Pro Hydraulic steering damper. This is now done and parts are being laser cut for delivery next week. When these are finished they will have to go off for anodising, black in my opinion, There will be two parts, a 12 mm thick spacer to fit below the new steering heads and then a rather curvy item which fastens below the steering head and spacer and links to the damper movable link. It will be supported in the hole in the lower part of the steering stem which will have to be tapped by the end user and here I need some feedback. All the dimensions of the parts on the dampers are metric and it makes sense to me to tap the hole in the steering head M10. However, on my own bike (the ex-Cecil Mills road bike) which I am using for design work this hole was already tapped 3/8 BSF. It would be useful if any of you who have any potential interest in this damper mod could have a look inside this hole. I thought that they were all just plain holes but if they are all tapped 3/8 then that will have to be the thread use. Thank you.
What has taken the time? Remember that the bearings are 32 mm O.D. and we need about one thou nip on that to ensure that the bearings are tight but not nipped up and distorted. One thou less than 32 mm is 31.975 mm which is 1.25885827 inches in old money. That is if there is wear due to the Oilite bushes having turned in the link, rather than on the eccentrics, then five thou wear means there is no interference fit. Well over half of the links worked on had this or more wear and so Loctite had to be resorted to. There was a four day delay while Loctite 638 was delivered. Even worse, several links were so badly worn that Loctite was not a solution and they had to be bored, sleeved and re-machined. There were even two which had previously been over bored and had reduced internal diameter bushes fitted to work on smaller than standard eccentrics. Beautifully done but a pain in the posterior. The one on which I have finally been defeated looked in perfect condition and machined up nicely. However when the bearings were fitted and a 20 mm diameter mandrel put through the bearings it was found that it was out of line by 3/16". It was heated, straightened and yesterday I fitted the third set of bearing, the first two sets having been destroyed. By this morning the whole thing had relaxed again and it was no longer lined up.
So that is where we are now. I should be able to start and send out parts next week to those who have not ordered AVO dampers or are having lower motion blocks anodise.
While this has been going on I have also been designing a set of parts to fit with a Chinese copy of a Hyper Pro Hydraulic steering damper. This is now done and parts are being laser cut for delivery next week. When these are finished they will have to go off for anodising, black in my opinion, There will be two parts, a 12 mm thick spacer to fit below the new steering heads and then a rather curvy item which fastens below the steering head and spacer and links to the damper movable link. It will be supported in the hole in the lower part of the steering stem which will have to be tapped by the end user and here I need some feedback. All the dimensions of the parts on the dampers are metric and it makes sense to me to tap the hole in the steering head M10. However, on my own bike (the ex-Cecil Mills road bike) which I am using for design work this hole was already tapped 3/8 BSF. It would be useful if any of you who have any potential interest in this damper mod could have a look inside this hole. I thought that they were all just plain holes but if they are all tapped 3/8 then that will have to be the thread use. Thank you.
Hi Just to bring you up to date. I have just contacted AVO and they tell me that it will be about another two weeks before the batch of dampers will be ready. Sorry for the delay but it allows me to get on with the 'HyperPro' Damper assemblies. Work is well under way on those with ten ordered.
