dropping radius arms on narrowed axles

[JonE]

Where the front axle has been dropped and narrowed by perhaps 1/2", are there any points to notice over radius arms which are being fitted with the 4 "drop" brackets rather than original-style castings?
I'm using some later radius arms with the second link removed, but noticed that when they are attached at the ball, one of them seems to want to kick out toward the inner wheel. I haven't tightened anything so may be worrying unduly.

Also, what bolts do people use for the dropping brackets from the original axle position? i.e. do the bolts need to fit firmly in the 1/2" hole in the body of the axle, or just ensure they are clamping well on the front and back faces? I've presenty got some huge metric ones which I can shim with a bit of brass... or I have some alloy spacers which fit really well and I can drill for a smaller cross-section bolt.

[Steve Jones]

The hole in the axle eye for the radius arms are 3/4", not 1/2". At least, all mine are, maybe yours are different? However, if 3/4" like all of mine, I've used 3/4" x 3" UNF bolts/nuts. 3/4" BSW and BSF are like hen's teeth and the UNF versions have the same size heads so look no different and are a perfect fit. Again, not that easy to find but I got mine from www.nuts-and-bolts.co.uk and paid just over £30 for two sets of bolts, nuts and washers for two axles including shipping and VAT.

Steve

[JonE]

sorry - 3/4 it is. I had some alloy bar and it fitted, but yes, its definitely bigger than 1.2" !
Thanks for the link Steve.

[dickie65]

Hi Jon.
If the axle has been lowered and has ended up narrower.
The geometry will change and as the axle is narrower something has to give so the radius arms will try and force the axle forwards.
Its simple geometry.
It can be challenging to get everything to fall into place.
Everything has to be loose when assembled including the spring shackles and spring clamps to see where things want to go.
If drop plates are used then they can be tweeked to allow things to fit.

[Hedd_Jones]

widening the axle back to its proper length isnt that hard to do Jon. You could probably heat it up on the barbeque, then have a couple of steaks when youve finished.

[MartinH]

Not exactly cheap but 3inch 3/4BSF available here

https://www.ebay.co.uk/itm/283831895653?...BMutW9suZf

P.S. they're a good source of all BSF and BSW Arun Fasteners in Arundel, Sussex.

[Hedd_Jones]

For what its worth, and in the interests of not spending money, why not just use 20mm bolts? 

Often 20mm bolts are a nice fit in 3/4 clearance holes. If not some gently tickling with a file will have a very nice fit indeed. 

Grind all the shite off the head and only a saddo like me would know they were metric rather than imperial, and you might actually have a socket in your socket set that fits.

And you can practically walk into most agricultural merchants and but them off the shelf.

[JonE]

So does that mean that the threaded end is less in diameter than the shank bit? I was presuming 20mm was 20mm, but see now there is a difference between effective and nominal diameter. Can someone explain please?

[Austin in the Shed]

Last week I wanted some 7/16 BSF bolts around 3 1/2" long so went out and bought some M12's longer than the threaded length I wanted.Turned them down and re threaded them and had to take about .010" off each hex flat to get the Whit size hexagon too,These M12 bolts were I think .462" about 010" down on true size.
The M20's may need more than a quick file to get to 3/4".Better if you've got a local friend with a lathe to reduce their size.If they're 2.5 pitch thread will be ok to use.
The original bolts were 3/4 along their plain dia reduced down the the (Austin std thread 5/8x14)