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-   -   Square Un-Tapered BB Spindles? (https://www.bikeforums.net/classic-vintage/1261919-square-un-tapered-bb-spindles.html)

Kilroy1988 10-25-22 09:02 AM

Square Un-Tapered BB Spindles?
 
Hello folks,

A little Google-fu has failed me. I purchased an exquisitely polished crankset made by/for Lambert modeled on TA Specialites design, and I'm quite positive it has perfectly square, untapered holes for the spindles. One conversation I found did mention that point regarding the Lambert cranks.

What are these spindles called? I'd like to find one that I can use to fit to a standard English bottom bracket. Cheers!

-Gregory

USAZorro 10-25-22 09:25 AM

They're called an awful engineering solution.

Once the crank arms get slightly worn, they will always have "play", since tightening the crank bolts won't do anything to make them more secure.

Possibly not the information you had in mind, but those two pennies were burning bright in my head when I read your post.

Kilroy1988 10-25-22 09:29 AM


Originally Posted by USAZorro (Post 22690572)
They're called an awful engineering solution.

Yeah, I realized that they would not be as solid as tapered ones, but you've already got me thinking I'll probably just cut my losses and re-sell the crankset. Oh, well. In my defense, I was unaware of this detail when I made the purchase and was hoping to make the best of it!

-Gregory

steelbikeguy 10-25-22 10:23 AM

as noted, not a great design.
Having said that, has anyone tried a fix? I've seen "bearing retainer compound" used on a FSA crank on one of my bikes. This compound is used to fill gaps and keep things fitting snugly. Perhaps it can help?
https://www.henkel-adhesives.com/us/...ctite_603.html

Steve in Peoria

merziac 10-25-22 01:02 PM

SS shimstock FTW, and loctite of some sort. ;)

merziac 10-25-22 01:06 PM

SS shimstock FTW and loctite/sg of some sort. ;)

T-Mar 10-25-22 02:29 PM

That spindle is almost certainly from the short lived Lambert/Viscount bicycles of the 1970s, which used lots of innovative and proprietary designs, not all of which were successful. The history is here; Lambert bikes

Square, non-tapered crankarm and spindle interfaces date back to the very late 1890s, during the original bicycle boom. Tapering the interface came later

madpogue 10-25-22 02:36 PM


Originally Posted by steelbikeguy (Post 22690645)
Having said that, has anyone tried a fix? I've seen "bearing retainer compound" .....

Perhaps you could incorporate a backup / Plan B option by using C-4.

dddd 10-26-22 09:52 AM

An extra-long strip of shim stock along each of the internal flats of the crankarm could effect a compression-fit upon installation of the crankarm.

The extra length should be toward the inside face of the arm, so that the shim can't move away from the targeted areas of contact.
The shims can be trimmed away after installation, difficult as that might be(?).

All this assuming that the OP can find the needed spindle and cups/bearings to position the spindle properly.

Viscount's pressed bb spindles had troublesome circlip grooves in them that can cause cracks to form.
And their bolt threading is NOT standard so you need the special bolts.

Prognosis: Grim.

unworthy1 10-26-22 11:27 AM

yep, cut your losses and cut bait, especially if it's just the crankset and not a Viscount/Lambert bike you are hoping to ride (with a new and better crank). If you had hopes to revive such a bike my advice is to cut Italian threads in the BB shell, then you can use Italian cups (but due to the intrusion of tube ends into that shell the easy path is to use a traditional "open" BB unit as sealed unit usually won't fit cause of this interference, unless you grind a away some tube ends, a real PITA.
For the spindle you don't HAVE to use an Italian piece since the BB shell is not 70mm wide but whatever spindle you choose it has to play well with the ITAL cups and bearings. Mix-n-matching sometimes creates new problems after solving an old one.

CliffordK 10-26-22 11:58 AM


Originally Posted by dddd (Post 22691626)
An extra-long strip of shim stock along each of the internal flats of the crankarm could effect a compression-fit upon installation of the crankarm.

Prognosis: Grim.

You'd only need to shim two flats. And thus potentially using thicker shim stock.

What is the comparison in crank spindle size between these Lambert cranks, and say either Campagnolo or ISO sizes?

tiger1964 10-26-22 12:36 PM


Originally Posted by steelbikeguy (Post 22690645)
as noted, not a great design.
Having said that, has anyone tried a fix? I've seen "bearing retainer compound" used on a FSA crank on one of my bikes. This compound is used to fill gaps and keep things fitting snugly. Perhaps it can help?
https://www.henkel-adhesives.com/us/...ctite_603.html

Steve in Peoria

Interesting. I have experienced a difficult-to-diagnose crankset squeak that I wonder if this product would help (non-Lambert).

dddd 10-26-22 06:47 PM


Originally Posted by CliffordK (Post 22691778)
You'd only need to shim two flats. And thus potentially using thicker shim stock.

What is the comparison in crank spindle size between these Lambert cranks, and say either Campagnolo or ISO sizes?

For that matter, a single shim with a 90-degree fold in it might be easiest(?).

oneclick 10-27-22 05:12 AM

Shims won't work; or if they do, not well or for long. The essence of the fit of a taper is that that there is a large surface area. If you get the small end of a tapered axle to fit - with shim - into the un-tapered crank, the whole of the fit is a line of contact at the end of the shim. The only way you get any area is by distorting that end into a wedge, but you still have only a small fraction of the area of a matching-taper fit. The crank will squirm; if you only have one flat shimmed it will also wobble; and that end of the shim will quickly be permanently deformed and the fit is then loose.

grumpus 10-27-22 03:58 PM


Originally Posted by Kilroy1988 (Post 22690542)
What are these spindles called? I'd like to find one that I can use to fit to a standard English bottom bracket.

I don't think you will - they were used with cartridge bearings pressed directly into an unthreaded bottom bracket shell; they had snap ring grooves that had a tendency to break the spindle*. Shouldn't be too hard to have one machined from scratch, but why you'd want to ...

*These were the same bikes that had a cast alloy "death fork" that was held to the steel steerer with a roll pin - that also had a tendency to snap at the obvious stress raiser.

dddd 10-27-22 11:11 PM


Originally Posted by oneclick (Post 22692361)
Shims won't work; or if they do, not well or for long. The essence of the fit of a taper is that that there is a large surface area. If you get the small end of a tapered axle to fit - with shim - into the un-tapered crank, the whole of the fit is a line of contact at the end of the shim. The only way you get any area is by distorting that end into a wedge, but you still have only a small fraction of the area of a matching-taper fit. The crank will squirm; if you only have one flat shimmed it will also wobble; and that end of the shim will quickly be permanently deformed and the fit is then loose.

I didn't read anyone here suggesting using a tapered spindle in the un-tapered crankarm.

The suggestion of using a shim(s) is to create some degree of needed interference fit with the straight bore and spindle, versus a tapered setup.

Obviously, only a very thin shim can be made to fit in a straight square spindle interface, cut long enough so it can't get pushed out of the way as the crankarm slides onto the spindle, then trimmed away after tightening.

But basically, using a straight square spindle and bore made of aluminum is kind of a nightmare, both in use and in manufacturing.

oneclick 10-28-22 02:21 AM


Originally Posted by dddd (Post 22693249)
I didn't read anyone here suggesting using a tapered spindle in the un-tapered crankarm.

The suggestion of using a shim(s) is to create some degree of needed interference fit with the straight bore and spindle, versus a tapered setup.

Obviously, only a very thin shim can be made to fit in a straight square spindle interface, cut long enough so it can't get pushed out of the way as the crankarm slides onto the spindle,

If the crankarm slides on, shim or no shim, there is no interference; hence a loose fit. On a straight spindle in a (too large) straight crank hole, tightening the bolt will not alter this.

I doubt it would be easy to make a shim strong and stiff enough at the correct thickness such that one could force it between the spindle and the bore; consider the pressure generated on the faces of a tapered connection. The end of the shim, on introduction, would be subject to the same pressure, while the free end behind it has nothing.

The only way it might work would be via differential thermal expansion; you'd be limited in what you could get from the crankarm (too high a temp for aluminium is quite low) so you probably would also want some co2 or liquid nitrogen for the spindle and shim.

rhm 10-28-22 04:45 PM

I once worked in a bike shop that had a couple Lambert cranks in the "junk" bin so (natch) i took them. Not finding a correct BB spindle i filed a taper onto the square hole. What angle did i use? No idea, i was 19 at the time and not much smarter than I am now (i think?). Did it work? Yes, no problems. If it got loose, i tightened the bolt down and rode on. Did i win any races? No. I wasn't racing. If you're racing you might want to shell out a little extra. But i was on a budget (working in a bike store, right?) and this suited my budget.

dddd 10-28-22 05:15 PM


Originally Posted by oneclick (Post 22693269)
If the crankarm slides on, shim or no shim, there is no interference; hence a loose fit. On a straight spindle in a (too large) straight crank hole, tightening the bolt will not alter this.

I doubt it would be easy to make a shim strong and stiff enough at the correct thickness such that one could force it between the spindle and the bore; consider the pressure generated on the faces of a tapered connection. The end of the shim, on introduction, would be subject to the same pressure, while the free end behind it has nothing.

The only way it might work would be via differential thermal expansion; you'd be limited in what you could get from the crankarm (too high a temp for aluminium is quite low) so you probably would also want some co2 or liquid nitrogen for the spindle and shim.

I do like the thermal-expansion idea!
Using stainless stock from a feeler gauge, I'm sure that one could get one or two sizes to fit even cold just by introducing a slight bevel to the square hole in the style of rhm's early bodge.
The stainless stock is quite tear-resistant and I'm nearly sure one could get the arm satisfyingly tight using strips of a thou or two!
Don't everybody run to their parts bins at once now!

cudak888 10-29-22 07:25 AM

FYI, nlerner gave me a Lambert crankset a few years back which I intend to swap to TA or Stronglight arms. Since I don't need the arms, anyone interested in experimentation is welcome to them for cost of shipping.

-Kurt

dddd 10-29-22 11:52 AM


Originally Posted by oneclick (Post 22693269)
If the crankarm slides on, shim or no shim, there is no interference; hence a loose fit. On a straight spindle in a (too large) straight crank hole, tightening the bolt will not alter this.

I doubt it would be easy to make a shim strong and stiff enough at the correct thickness such that one could force it between the spindle and the bore; consider the pressure generated on the faces of a tapered connection. The end of the shim, on introduction, would be subject to the same pressure, while the free end behind it has nothing.

The only way it might work would be via differential thermal expansion; you'd be limited in what you could get from the crankarm (too high a temp for aluminium is quite low) so you probably would also want some co2 or liquid nitrogen for the spindle and shim.

I realize now that you were thinking that the shim(s) need to be forced in, as opposed to using an over-length shim(s) and leaving extra length hanging out of the hole from the side that the spindle gets pushed in (as I described in an earlier post, quoted below):

"An extra-long strip of shim stock along each of the internal flats of the crankarm could effect a compression-fit upon installation of the crankarm.

The extra length should be toward the inside face of the arm, so that the shim can't move away from the targeted areas of contact.
The shims can be trimmed away after installation, difficult as that might be(?)."


As described above, the shim is getting wedged in by the installation of the crankarm (assuming that the special Whitworth-threaded bolt is perhaps long enough to get things started).

Hopefully though, nobody here has to actually deal with any of these dreadful non-tapered crank interfaces on a bike that will be ridden much!

oneclick 10-29-22 03:27 PM


Originally Posted by dddd (Post 22694593)
I realize now that you were thinking that the shim(s) need to be forced in, as opposed to using an over-length shim(s) and leaving extra length hanging out of the hole from the side that the spindle gets pushed in (as I described in an earlier post, quoted below):

"An extra-long strip of shim stock along each of the internal flats of the crankarm could effect a compression-fit upon installation of the crankarm.

The extra length should be toward the inside face of the arm, so that the shim can't move away from the targeted areas of contact.
The shims can be trimmed away after installation, difficult as that might be(?)."


I knew what you meant.

And to make sure you do as well, I doubt it very much that one could persuade a shim of sufficient thickness to effect the necessary fit between the crank and the hole - by physical manipulation of *any kind*. If the crank is on the axle the shim won't go in, and if the shim is on the axle the crank won't go on.

dddd 10-29-22 10:22 PM


Originally Posted by oneclick (Post 22694756)
I knew what you meant.

And to make sure you do as well, I doubt it very much that one could persuade a shim of sufficient thickness to effect the necessary fit between the crank and the hole - by physical manipulation of *any kind*. If the crank is on the axle the shim won't go in, and if the shim is on the axle the crank won't go on.

I'm thinking you're still not getting it.

The shim goes in the hole before the arm is installed, not after. The only force is from the bolt.

Quoting an earlier post of mine again: "Using stainless stock from a feeler gauge, I'm sure that one could get one or two sizes to fit even cold just by introducing a slight bevel to the square hole..."

With a bevel at the hole's entry, surely the bolt could generate quite a bit of interference fit of the arm on the spindle, equivalent to what is generated on a tapered spindle.

oneclick 10-30-22 07:35 AM


Originally Posted by dddd (Post 22695004)
I'm thinking you're still not getting it.

The shim goes in the hole before the arm is installed, not after. The only force is from the bolt.

Quoting an earlier post of mine again: "Using stainless stock from a feeler gauge, I'm sure that one could get one or two sizes to fit even cold just by introducing a slight bevel to the square hole..."

With a bevel at the hole's entry, surely the bolt could generate quite a bit of interference fit of the arm on the spindle, equivalent to what is generated on a tapered spindle.

The shim WON'T go in after you put the axle in the hole. If you make a bevel it will go in as far as the bevel; no further.
The crank WON'T go on after you put the shim on the axle. If you make a bevel it will go on as far as the bevel; no further.

If you do get the end of a shim shoved in to that bevel, tightening the bolt won't do anything to the shim unless you make the crank move on the axle. If it does move, it will push the shim along with it.

And with a straight bore and straight axle, changing the position of the crank on the axle (by tightening the bolt) does nothing to decrease any existing clearance between the crank and the axle. An interference fit requires a negative clearance (a loose fit is by definition positive clearance).

cudak888 10-30-22 08:17 AM

Instead of a solid shim, has anyone considered using a liquid shim, such as Loctite 609 (fills gaps up to 0.01") or 603 (gills gaps up to 0.015" + for oily surfaces)?

-Kurt


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