Options for re-engineering track rod ends / heims

[dangerous doug]

Could you not work out the taper by using Pythagoras followed by sin/tan/cos?

[Red8eard]

Vulcan - So is EN24T like "5 better" than EN19T? as I said I know just enough to know I don't know enough, my concerns over metallurgy are that it's easy to make something balls hard, but you don't necessarily want that in a TRE. The failure mode really wants to be bending rather than breaking. I'd consider sending a dead TRE off to a testing house to actually determine the correct metallurgy & treatment rather than guess at something that's "probably" good enough. There's also the fact that most parts like that (half shafts included) are not "base" material but are heat-treated after production, so just machining a part from the same base does not guarantee it'll actually be strong enough. We know the Volvos have some serious metallurgy in them, they didn't muck about when they made them.

The other issue with manufacturing TRE's is that there's plastic/teflon inserts and whatnot in there, not just a ball & socket.

If it were possible to work out all the specs I'd be well up for a short production run of TRE's, but as I said I'd really want to know the specs were pukka and worked out by an adult who'd be happy with the part being fitted to a vehicle used on the road.

Daan - I don't have the kit to accurately measure the taper, it's around 6.5deg angle from the centre line, top of the pin (by Lemforder's spec) is 17.55mm, same as the P38 and LR pins but obviously differing on length & taper. Sometimes they measure the tapers in inches-per-foot and other weird measurements so it's hard to be certain, what can seem like a very strange number in degrees can turn out to be a more obvious "round" number in another unit.

I have no doubt there's hundreds of other TRE's out there that fit, but short of rummaging through every box in a (very understanding) parts depot with a vernier calliper you simply can't find out which ones out of the thousands might actually work.

At this point I'm ignoring the relatively simple task of making a steering rod if it should be required, until I've worked out the plan for the TRE's there's no point thinking about arms.

Just a Note on en24t and 19t the t actually stands for treated, harder to machine but less rework, however it means usually a maximum blank thickness of 140mm you can also buy it non treated and heat treat it after. Tbh i would go to a scrap yard and find a newer vehicle with TRE that are cranked and correct. and work from there.

[FridgeFreezer]

Doug - Certainly, the issue is having accurate enough measurements to start from, a fraction of a mm error changes the angle a fair bit at this scale. I don't know how critical it is on a part like this.

[landroversforever]

Any inaccuracy in the taper is going to stop it being snug and introduce movement to it I recon. Not something you want in a steering setup.

[vulcan bomber]

It's simple trig to sort the angle out...

Serious half shafts want making from En36C or s157.... Having made gearbox shafts that handle 600 plus HP, I do know a bit....

EN24T will bend a heck of a long way before it breaks.

You can send one for testing it's material grade, but you need to take into account there usually forged or cast.... You certainly won't be able to afford taking that approach.

If you remade the worn bits, phosphor Bronze could be used instead of Teflon, I doubt they would ever wear.... Not that Machining Teflon is difficult.

[De Ranged]

Having been down similar paths with various clients.... my view is make the replaceable wearing parts as common as you can, so I'd suggest reaming the arms

Looking at your examples of the different BJ's I think you may find the toyota dyna light truck has a similar BJ taper to what you want, this is what I'm using to make HD tie-rods (I'm reaming the arms and pitman arm to fit these, same fat dia but bigger thin dia)

""

Catch is they don't do a long arm for attaching your drag link and they are short if you go down this path your going to have to build a bent tie-rod with a mount for the draglink

I'm going to be at my shed this evening working on a mates truck so I'll grab a part number for you to try

[Gazzar]

Not much to add, other than maybe a visit to a tractor scrapyard may work, mf165 track rods are about a foot long and are good to turn wheels that are a long way from the axle. They could be cranked, I suppose. Otherwise a plant or truck scrapper would be a good place to hunt moderns stuff to match.

http://www.ebay.co.uk/itm/Massey-Ferguson-Push-In-Track-Rod-End-Outer-165-590-/261948603899?hash=item3cfd5a7dfb:g:ZU4AAOSwNSxVK-Jd

G.

[B reg 90]

I found this web site useful. See link below.

www.vapourmatic.com

They list by part type, so you can look up 'steering joints', then '4wd' then by a very handy 'cranked arm' section. Then it gives you a table of all the joints they do. Pick one you like the look of and it will then tell you what it is fitted to (as long as it is a tractor!)

I found a nice cranked joint. But I did need to ream out the taper.

[Tal]

Why are the holes tapered? Is it purely for doing the nuts up?

I am pretty sure its because It is more likely to be removable in the field with simple tools (military and agricultural vehicles in particular) but I believe its because it allows the joint more movement and adjustment after fitting without failure and like a tapered bearing, can be tightened without having to do a refit

[miketomcat]

If it was a parallel hole it would be impossible to stop it rotating whilst tightening. With a taper a little pressure causes enough friction (normally) for you to tighten.

Mike

[dangerous doug]

This of any use to you?

http://littlemachineshop.com/reference/tapers.php

You might be able to identify what flavour taper you have

[ejparrott]

I am pretty sure its because It is more likely to be removable in the field with simple tools (military and agricultural vehicles in particular) but I believe its because it allows the joint more movement and adjustment after fitting without failure and like a tapered bearing, can be tightened without having to do a refit

If it was a parallel hole it would be impossible to stop it rotating whilst tightening. With a taper a little pressure causes enough friction (normally) for you to tighten.

Mike

That's not quite the point I was working on. I know parallel hole you can't tighten the nut, but the point is, as I said earlier, why don't they use a parallel hole and a clevis TYPE of fitting, one where the pin passes right through and both sides can be accessed

[lo-fi]

I'm pretty sure the tapered hole is more to do with fit than being able to tighten the nut because the taper grabs... Look at it this way: a parallel bolt has a fairly fine tolerance between being interference and clearance. In between is what you'd call a "fitted bolt" - one where the hole is precision reamed to a known dimension, then a bolt machined to fit it exactly. Ever seen your average auto mechanic with a reamer? Not so much. It isn't really automative tech, or not in that environment anyway. The tapered hole "fits" itself. You take out any inaccuracy in fit caused by manufacturing tolerance just by winding the nut on. The other advantage is wear resistance. The parallel joint, if it's not perfect, will allow a small amount of movement under load, and movement leads to wear and more movement. The tapered bolt is held fast in the taper under considerable tension and really *can't* move laterally.

[simonr]

What I would do - and indeed have done - is buy the joints you want, measure the taper as accurately as you can then order a tapered reamer with the same angle. Ream the existing holes to the right size and bolt together. Simples!

If you don't want to buy a reamer, you could just machine down a drill bit to a taper - it only has to drill a few holes after all.

Si

[ToyRoverlander]

As for Heims, I'm using the ones from Ruffstuff offroad in the US, very good quality Heims! After 4years of daily driving, in winter as well, there's still no play in them.

[Fatboy]

Could you not take a cast of the tapered hole, section it then accurately measure the taper angle on an optical comparator? If you don't have access to a comparator, I'm sure someone on here has. You could take the cast and post it to them, measurement should only take 10mins.

[vulcan bomber]

Or just send the old joint?

I can stick one on our shadowgraph at work to find out the important bits.

[ejparrott]

Or, thinking about it, I could give a spare LR TRE to the inspector at work to measure on the CMM, should have thought of that sooner, I'll have a word

[vulcan bomber]

It can also go on our CMM.... Shadowgraph would be ample for this though.

[B reg 90]

To measure taper I clamped a track rod end to my milling machine table with the taper sticking up vertically. Then measured the taper as follows:

Put a lever dial gauge in the chuck and sit it against the ball joint taper at 12 o'clock (top view). dropped table 0.200" and then read off change on lever dial gauge. Repeat on the other side (6 o'clock), then calculate the angle on both sides using trigonometry and average - this means you don't need to have the ball joint sticking perfectly perpendicular to the milling machine table. If you feel super accurate repeat at 3 and 9 o'clock.

Then look up 'Xkut reamers' on internet and order a taper reamer to suit. If I remember rightly there are some slight/tiny differences between the ball joint taper and the taper reamer.

Adrian

[B reg 90]

You could also try AM Steer (www.amsteer.co.uk) -they seem to make and refurbish custom track rod ends if you want to fix your current 'ends'

[FridgeFreezer]

Cheers guys, some good info & further reading to do in all that now I'm back from me hols... going to have to refit the slightly worn one for Seven Sisters next weekend as I'll not have time to sort anything "nice" before then.

ejparrott - I think tapers give a secure/snug fit with zero play once the nut's done up, even if the hole is not perfectly to size through wear or tolerance, whereas a pin + clevis relies on a very close fit (hole diameter) and once it's worn loose it will rattle no matter what you do. If the tapered hole is worn or oversize the pin will just sit a fraction lower in the hole & still give a solid fit.