Vic, the way that I understnd this, and I am an astronomer, not an engineer, is best understood by considering a friction damper. They are hard to start moving and then move easily, The expression we use here is lots of stiction and then not much friction. Compare that with hydraulic damper.. I have not seen a friction damper on a car suspension for decades. I think there is a reason.
Jig to Hold Head in Lathe
- Thread starter Marcus Bowden
- Start date
Bruce, you caught my error and I edited it. There's room. 92x120.
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Good Luck John,
I thought I had seen somewhere, Anything over 102 Stroke ,
And the Piston Speed would be too much at 6000,
Is that overcome by Nikasil Bores ?.
Cheers Bill.
I thought I had seen somewhere, Anything over 102 Stroke ,
And the Piston Speed would be too much at 6000,
Is that overcome by Nikasil Bores ?.
Cheers Bill.
When having the mod on Girdraulics links for needle or ball bearings the easy and simple way would be the line reaming with piloted reamers. These are essential for any girder overhaul and without them it will be a crap job. But before reaming one has to check links for twist and parallel axis of all spindles so it would not be a surprise to me to find all sorts of flaws in used parts - which can be the root of excessive friction within standard used Girdraulics and not really the plain bearings to blame. I wonder how companies deal with the ball bearing mod on these links without piloted reamers. Vincent Speet made a jig for the mill to get this job done - the laborious way. But in cruel life I am sorry to say the ball or needle bearing mod can be a way to conceal poorly aligned link arms as you don´t feel the crooked bores by spinning the new spindle in these bearings.
Still I cannot believe that friction in standard bushed Girdraulics to be more than 10 percent of extension or compression forces in the hydraulic damper and effecting the ride much. But then my thinking would be based on correct geometry in all girder components. Conditions will be a lot worse in thoroughly mangled forks and ball bearings will have a huge effect , but then the plain bushes are not to blame when really the poor condition of various components is the root of the drama, so the ball bearings are just to gloss over deeper based defects.
Below a set of Hunger piloted reamers, biggest in my stock is up to 45 mm. I´d think for not so small runs of ball bearing mods it should pay to get one of them , 33 mm o.d. ?? Also for line reaming standard bushes I´d accept no other tools - crap tools will produce crap jobs typically. New reamers up to34mm can be € 200-300.- but they turn up in Ebay used . Don´t get Indian or whatever reamers, junk as you want adjustable reamers with uneven spacing between blades. Otherwise you´ll have chatter marks and out of round bores - useless.
Vic
Still I cannot believe that friction in standard bushed Girdraulics to be more than 10 percent of extension or compression forces in the hydraulic damper and effecting the ride much. But then my thinking would be based on correct geometry in all girder components. Conditions will be a lot worse in thoroughly mangled forks and ball bearings will have a huge effect , but then the plain bushes are not to blame when really the poor condition of various components is the root of the drama, so the ball bearings are just to gloss over deeper based defects.
Below a set of Hunger piloted reamers, biggest in my stock is up to 45 mm. I´d think for not so small runs of ball bearing mods it should pay to get one of them , 33 mm o.d. ?? Also for line reaming standard bushes I´d accept no other tools - crap tools will produce crap jobs typically. New reamers up to34mm can be € 200-300.- but they turn up in Ebay used . Don´t get Indian or whatever reamers, junk as you want adjustable reamers with uneven spacing between blades. Otherwise you´ll have chatter marks and out of round bores - useless.
Vic
Neue verstellbare Hunger Handreibahle z.B. Achsschenkel U 29-34mm ex Bundeswehr | eBay
Länge gesamt : 418 mm. Neu und unbenutzt aus ehemaligem Lagerbestand der Bundeswehr. Vierkant : 16 mm.
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On the large eyes on the lower links i don't machine or line ream them to suit the 32 mm sealed ball bearings, these i get parallel honed on a Sunnen hone.....this not only gets the bore size exactly the right diameter but both eyes are done together keeping them true to one another. You need about 3 or 4 tenths of a thou interference as too much will crush the outer races and the bearing will not spin freely.
Greg, you seem to have been lucky most of times with honing the lower links as Norman has found quite a few oversize for ball bearings. I wonder what sort of Sunnen your mechanic got for this job ? As both sides of the links are very far apart the hone needs very long stones for staying in both bores all the time during honing operation . My guess the link has to be turned around quite often for having both sides at same size in the end. So this must be a very special Sunnen type and I think you get even a new a Hunger reamer for 32mm easier and less expensive than this Sunnen. No photo available of that hone ??
Vincent Speet went to 33 mm for the needle bearing, a whole millimeter more is a bit much for a reamer. In that case I´d have each bore on the mill plus boring head, roughly centered each time and keep some undersize left. So for perfect alignment and size I´d do the reaming in last stage, knowing that alignment is safely achieved. Piloted reamers are exactly the right tool for aligning bearing seats wide apart. And yes, my choice would be needles like Vincent´s idea - sealing the lot is another matter.
Vic
Vincent Speet went to 33 mm for the needle bearing, a whole millimeter more is a bit much for a reamer. In that case I´d have each bore on the mill plus boring head, roughly centered each time and keep some undersize left. So for perfect alignment and size I´d do the reaming in last stage, knowing that alignment is safely achieved. Piloted reamers are exactly the right tool for aligning bearing seats wide apart. And yes, my choice would be needles like Vincent´s idea - sealing the lot is another matter.
Vic