Topic: Auxiliary Axle Shaft for Truing/Balancing? CB500/550

[Kenzo1979]

Always good to poll the forum before I buy something...

So I have a wheel balance stand, but I don't care for the rod (with the cone/set screw shaft locks that wedges in/against the bearings).  Since all of the bikes I mainly deal with have a 15mm front axle and 20mm rear, I figured why not just have lengths of solid round stock in those sizes to use on the stand?  Only need to be 12 inch lengths.  I can get them from McMaster-Carr relatively cheap and there are products described as tight-tolerance that I'm guessing would be the best choice. 

So my question is, If I purchase these, will it work, or am I going to run into an issue with the fit on the ID of the wheel bearing?...either not passing through or too loose.  What's my wiggle room...tenths, hundredths, thousandths mm?  So I can be sure what I order is correct.

Attached is the link to the McM-Carr site, metric solid round stock.

https://www.mcmaster.com/products/round-stock/system-of-measurement~metric/shape-type~rod-1/

[Tracksnblades1]

79..

In our area (heart land) we have standard hot and cold rounds and the various types within those two.
The actual round OD like for example stress proof shaft is undersized so a 2.000 ID bearing will fit on the 2” shaft with out pressing it on. With the collet type bearing it’s not as bad as it once was. When tightening a bearing with set screws locks, it basically jacked the bearing to one side because of the clearance.

Another option we have locally is “precision Shaft”. A 2.000 inch shaft will measure 2.000 inch or a zero press fit for a true 2.000 ID bearing or hole. The only problem comes if you want to slide something over the shaft a foot or so before locking it down. Because it will require a lot of shoe shining it with strip emery cloth sand paper to achieve a slip fit if desired…

[willbird]

I have a set of gage pins the right range. A .590"- pin slides into a new AllBalls CB750K front wheel bearing and a .591- does not slide in. I also have a vapor blasted CXB750K front axle which measures .5893". Maybe that info might give you some ideas.

Looking at the Mcmaster "tight tolerance" 12L14 they say -.012mm plus 0. That puts the  size range at .59007756" to .59055"...you MIGHT need to polish them down .0005" to .001" or so maybe? Their straightness tolerance is 1/16" per 3'....should not matter for this use ?? The 12L14 would be fine for this use IMHO, it machines like butter, only down side is that due to the L for "leaded" it does not give a high strength when welded. 12L14 is my go to general purpose steel when I buy "bar ends" from Ebay :-).

I need to buy or build a wheel truing/balance stand myself so this is all interesting info.

Bill

[ofreen]

So I have a wheel balance stand, but I don't care for the rod (with the cone/set screw shaft locks that wedges in/against the bearings). 

Why not? Just curious.  It seems to work very well on the stand I have.

[Kenzo1979]

Thanks for all the feedback so far.

Ofreen, it’s fine for balancing, and I’m not sure what you have exactly, but mine is cheap Harbor freight.  Even though it’s a pretty simple device, the cone spacers have some wiggle room on the shaft, and when you Tighten the set screws down, I believe that the set screws fudge it off on an angle  slightly.  To the point where I can’t trust the lateral sway if I’m truing. Now another thing that would be great about having the Shaft that matches the wheel, would be that after I setting up a wheel, I can put them back on the old rod/cone spacer setup and see if there’s any difference.

[willbird]

Thanks for all the feedback so far.

Ofreen, it’s fine for balancing, and I’m not sure what you have exactly, but mine is cheap Harbor freight.  Even though it’s a pretty simple device, the cone spacers have some wiggle room on the shaft, and when you Tighten the set screws down, I believe that the set screws fudge it off on an angle  slightly.  To the point where I can’t trust the lateral sway if I’m truing. Now another thing that would be great about having the Shaft that matches the wheel, would be that after I setting up a wheel, I can put them back on the old rod/cone spacer setup and see if there’s any difference.

I kinda wondered about the Harbor Fright device.........

[ofreen]

Ofreen, it’s fine for balancing, and I’m not sure what you have exactly, but mine is cheap Harbor freight.

The Harbor Freight stand is all I have too.  I also looked at the one Motion Pro sold that looked just like it for quite a bit over twice as much as HF wanted for theirs and saw no real difference.   The main ways these can fail to be satisfactory is if the rollers don't turn freely. or the shaft is not straight  Both are good on mine and the set up is very sensitive.  The cones on mine are a close slip fit on the shaft so I don't see any significant offset when the set screws are tightened.  But Harbor Freight is what it is, so it wouldn't surprise me if other examples weren't as good.  Some things from HF are crap, but some things are OK.  Sadly, nearly everything is made in China these days, even from the great old-time names. 

[BenelliSEI]

You guys are right. I use the cones/shaft for balancing. For truing, my stand has a set of threaded bushings on the legs that take two large, threaded rods with a fixed cone on the ends. That’s what I use for truing. The wheel doesn’t turn so freely, but it doesn’t wobble on loose cones or move side to side.

You can see the threaded bushings just below the axle/bearings in this photo. I forget where I got this one, it was on sale. The “legs” have multiple screw holes in the base so I can open it up for wider wheels/tires. I gave my other stand away after I used this one.

[M 750K6]

For truing, I put the axle in the soft jaws of my vice with a very slight upward tilt.

[Kenzo1979]

So I decided to just get a pair of axles (front and rear) off eBay and alter my HF stand by drilling new holes for the posts to accommodate the lengths of the axles as opposed to the length of the original balance rod that came with the stand.  Worked out great.  Just respoked two rear wheels and trued them.  When I do the fronts, I’ll share more pics.  Cheers, everyone, Safe Riding!

[BenelliSEI]

Very smart. I’ll be looking more closely at mine, next time!

[rotortiller]

This is all I use for lacing and balance. It can use cones or axle on its roller support. Cones are best for truing, rollers are best for balancing.

[CB750R]

I too found the stock cones had too much play on my generic truing stand I got a length of that precise steel rod and made my own cones on the lathe with acetal. I used a 1/2” ream to get a tighter slip fit for the cones. For now I’m happy with the results.

[grcamna2]

This is all I use for lacing and balance. It can use cones or axle on its roller support. Cones are best for truing, rollers are best for balancing.

I have the same truing stand as you have above;I also found the long,threaded/adjustable bolts/cones(the cones have allen screws, & I left them a little loose..  )below the top balance bearings on both sides of mine 'out of true',so I used the top shaft/cones with the bearings up above and centered it 'ok'  with the two o-rings holding it in position.
I want one that's more precise,but this one 'will do' until then..
I've seen some nice,heavy cast iron vintage truing stands in the past,which look very precise.

[rotortiller]

Mine works fine, I have balanced and gone over 220kph on my R6 with no vibration using the mandrel on the tool's top bearings. For truing with cones the runout depends on bearing accuracy as the inner race is held. I compared my eco tool and mandrel with another aircraft grade tool employing knife edges, levels with axle and got the same results. Because the axle rolls on a knife edge or tool bearing cradle any runout will screw balance when it rotates on the wheel bearings You just have to take care and reposition the wheel in the mandrel (with o-rings) or axle to verify accuracy if concerned. The other thing is being practical in your results, you can spend an hour being anal but after the first ride when things seat a bit it will be slightly different. I watch guys spend excessive time on a rear wheel assy and then throw on the cushion drive and sprocket later. Because these bikes are low tech tanks with limited top speed makes it less critical than a modern performance motorcycle.

[grcamna2]

Mine works fine, I have balanced and gone over 220kph on my R6 with no vibration using the mandrel on the tool's top bearings. For truing with cones the runout depends on bearing accuracy as the inner race is held. I compared my eco tool and mandrel with another aircraft grade tool employing knife edges, levels with axle and got the same results. Because the axle rolls on a knife edge or tool bearing cradle any runout will screw balance when it rotates on the wheel bearings You just have to take care and reposition the wheel in the mandrel (with o-rings) or axle to verify accuracy if concerned. The other thing is being practical in your results, you can spend an hour being anal but after the first ride when things seat a bit it will be slightly different. I watch guys spend excessive time on a rear wheel assy and then throw on the cushion drive and sprocket later. Because these bikes are low tech tanks with limited top speed makes it less critical than a modern performance motorcycle.

Looks like you have yours set-up well.

[willbird]

I too found the stock cones had too much play on my generic truing stand I got a length of that precise steel rod and made my own cones on the lathe with acetal. I used a 1/2” ream to get a tighter slip fit for the cones. For now I’m happy with the results.

My first try was just truing up by machining the HF cones with the set screws set 180 degrees apart, it seemed to work well considering all it cost was some time if one has a lathe.

Bill