Bronze bushings vs needle bearings

[dingleberry]

I am in the process of converting the 400 to accept an XT250 swingarm for my chain conversion (not yet done). The 400 has a fancy looking needle bearing set up compared to the XT which just uses bushes. Is there any appreciable advantage to using the former? Would probably be a whole lot simpler and cheaper if I went the XT way. Any thoughts on this?
Have also mocked up my VT500 front end and looks like a simple fit, stem diameter and length is good. The VT has air valves, factory fork brace/mudguard bracket, but is about an inch too long. Just have to slide them up the clamps a bit. Unfortunately will increase the wheelbase maybe inch and half but I think looks better than trailing axle setup. Will also save me a rebuild as both sets of my 400 forks are bad.
   

[The Prophet of Doom]

Are you going to buy or make them?  Bronze is eye wateringly expensive - dearer for the material alone than the full needle bearings.  You will also need to buy some more tooling and a new lathe.

The VT triples seem to have a lot less offset than the XZ - that will shorten your wheelbase

But if you are going to that bother, why not a pair of upside down forks?

[dingleberry]

Was planning on making but hadn't looked into it yet. Didn't realize bronze was so expensive. It would be a great excuse to upgrade my myford lathe. The vt has a little less offset but not enough to equal the trailing axle of the vision. Upsidedown forks will cost more than I want to spend on this bike. It's more a learning project to hone my skills on. A first build of many more I hope.
What are standard factory bushes made of? Hardened steel or soft?

[dingleberry]

Have done a bit of reading and it would seem a few guys have used Delrin or equivalent to machine new bushes from. This may be a cheap alternative for me and get to do a bit of DIY at the same time. What sayeth you Doom-meister....

[Blake]

Have done a bit of reading and it would seem a few guys have used Delrin or equivalent to machine new bushes from. This may be a cheap alternative for me and get to do a bit of DIY at the same time. What sayeth you Doom-meister....

Does anyone know the exact dimensions of the stock bushings?   might be an easy way to source bushings from another bike/ another aftermarket supplier for a different bike.  e.g. xs650 swingarm bushings are only 30 bucks.

[fret not]

I have yet to take mine apart to measure, but there are many configurations of ready made bronze bushings from industrial suppliers.  Here in the States are McMaster-Carr, and MSC, as well as some general bearing supply shops.  I don't know what is available in other parts of the world. 

[The Prophet of Doom]

Have done a bit of reading and it would seem a few guys have used Delrin or equivalent to machine new bushes from. This may be a cheap alternative for me and get to do a bit of DIY at the same time. What sayeth you Doom-meister....

Really - Delrin? 

Delrin is great stuff - machines beautifully, nice and light, and well cheaper than bronze, and about 1/3 as tough. I'd not have though about using it in a swingarm, but I just don't know .  Racer guys seem to love their bronze bushings.

Whichever material the axle hole is pretty small - too small to use a boring tool so it would need to be reamed to be a good enough tolerance (twist drills are too sloppy) so there's $80 in tooling.

[dingleberry]

Think I have an old bit of HSS that's been made into a boring tool, that should be narrow enough to do the job. From what I've read there seems to be different grades of hardness in the Delrin range, and those who have done it have used the hardest of course.

[fret not]

What sort of prices have you been quoted and for what size material?  At MSC Industrial Supply I found oil impregnated bronze round stock 1 1/8" X 6"+ for about $35usd.  They have other varieties of the material, "bearing " bronze, and just plain bronze. 

Do you have any "surplus" material dealers?  About an hour drive from me there is a place called "Blue Collar Supply" that has freight damaged stuff, recycle materials, and remnants of larger pieces, round, square, hex, sheet, angle, etc. plus threaded fasteners of many sorts.  Check with race shops to find sources.

[The Prophet of Doom]

$70 a foot is pretty outrageous, but it's about four times that here and just one place I know of that will sell cuts - other than that and it's 4 metres at a time.   

It's hard to know what to pick - my book has over 30 different bronze alloys in it - at least half are "bearing" bronzes.

[fret not]

$35 for 1/2 ft. but only need a couple inches to make bushings.  No need to buy a whole foot or more.

Cast iron would work as would mild steel, just keep it lubed.  An old re purposed truck axle would supply a lot of strong material for not much investment.  A lot of old Honda swing arm bushings are ferrous metal, you can tell because they will rust.  Not magic, just need to be the right size.

[dingleberry]

Aha, this helps. I might use steel for a start before things get serious. Can replace at a later point in time. This will be easy and cheap so if things change or I botch something no big deal.