My E30/R5Turbo track car - Gearbox MkIII

[sean_318i]

Geoff dont stop posting there is a silent majority of us out there reading this thread.
I dont have much time to spend on the zone but I still have a look around every few days, this thread is one I always check for updates and read thoroughly.
Your design process, attention to detail and explanations mean I never need to ask a question, I dont post much anyway, keep it up.

Sean

[Ziggy]

Certainly still reading here! Epic thread.

[GeoffBob]

Thanks Gents for the comments/replies. I will continue to post up on my progress as I go along, albeit at a fairly slow pace these days . At such point as I have to start casting my own materials I may resign from this project, but until that day arrives I am in for the long haul. I think I have already proven that it is possble to make ones own gearbox, it's now only case of ironing out the creases and I'll be back down the local track again. I keep reminding myself of this as self motivation. I have to say that it was incredibly dissapointing for me that my gearbox packed in on the same day as I was testing my new wastegate. I was having so much fun at the time ....

[GeoffBob]

That new design looks much stronger with the teeth facing in-over rather than out over (or is that the selector and the dog ring is still the inner with the larger radii). As you have mentioned previously if you keep an eye on any radii then they should be pretty much indestructible for what you need. I'm pretty sure there is some math which I have never learned (or have forgotton) which will help you calculate the most effective radii (without removing too much material) but I'll leave that ball well and truly in your court as your way smarter than me when it comes to that (I rely too much on SolidWorks to do the hard work for me). :

With reference to the pic I posted earlier: The selector ring (olive-green) is still on the outside with the dog-ring (puke yellow) on the inside. The difference (compared to the prior design) is that the dog-ring is now integral with the gear-hub (pinky-orange) in the centre. IE: there are no splines (to come loose) between the dog-ring and the hub, they are made from one and the same solid. With the splines gone I had the room that I needed to insert the much needed radius at the base of the dog-teeth. The big issue here is that the teeth can survive banging around inside the selector ring due to the excessive backlash. IE: the right-hand face of the dog teeth engage with the left-hand face of the selector-ring teeth during acceleration, and the other way around during engine braking. This is, I am sorry to say, the way a synchroless gearbox works, and without that backlash it would be nigh on impossible to shift a gear.

FYI, I have a FEM modelling tool here at work called "Abaqus" that I am trying to learn. I want to use it highlight any stress concentrations on the parts I designed. I'll get to it one day. For the time being I rely on some fairly simple calculations scribbled on the back of a cigarette box. I have SolidWorks as well, but I am pretty useless with it. I've been using Turbo-CAD since the early nineties so I tend to stick with what I know (it's also quite cheap) but I really should make the change to SolidWorks at some point.

[GeoffBob]

... and if you do leave the forum, I'll swim to S.A and kidnap your heat treatment guy (assuming no body beats me to it at the traffic lights...or kidnaps me at the traffic lights) and I'll hold him to ransom until you post another update.

No worries Chris, I'll be here for a while yet. I was having one of those moments when I needed to feel wanted, and wanted to feel needed.

[billgatese30]

That all makes sense to me now Geoff, seems like a much better design now. You really need to get onto Solidworks though, I had to use normal Autocad the other day and I swear I've forgotten how slow it really was to use. I learned it at college and then used Solidworks when I got to work and realised what a breath of fresh air it is to use.

[appletree]

Talking to yourself Geoff? There's not many who can offer meaningfull inputed to this thread at the level you are now working at. We just sit here reading your posts in ore and post the odd "top progress" "nice work" comment!

I for one am still reading with interest!

Nice work

[GeoffBob]

Talking to yourself Geoff? There's not many who can offer meaningfull inputed to this thread at the level you are now working at. We just sit here reading your posts in ore and post the odd "top progress" "nice work" comment!

I for one am still reading with interest!

Nice work

Thanks Matt Don't think for one moment though that I wasn't in awe of your Getrag 420g project! How's that panned out BTW, are you happy with the result. Six gears must be a dream.

Good to see that you are still around too.

[GeoffBob]

... You really need to get onto Solidworks though, I had to use normal Autocad the other day and I swear I've forgotten how slow it really was to use. I learned it at college and then used Solidworks when I got to work and realised what a breath of fresh air it is to use.

You are so right Chris. I have the sofware and the training manuals here at work, but I never got any further than doing a few of the arbitrary tutorials. Sadly, for someone who started out designing parts on an old fashioned draughtsman’s table, I find Solidworks counter intuitive. TurboCAD is much like drawing with pencil and paper, but on a computer. I do, however, plan to make the transition at some point.

[GeoffBob]

And in today's news .....
My bar of M120 has arrived at the Bohler offices in JHB. From there, Bohler will deliver it directly to ARMA gears in Germiston. As soon as it's with ARMA gears I'll take a drive down to Germiston to deliver the new drawings.

ARMA gears are still the only company I could find locally who are prepared to take on my project for me. I hope to solve my past problems with regular QC visits and no payment until I have signed off on the job. Short of making the parts myself there's nothing more I can do.

[Rav335uk]

BTW, with the exception of the "regulars" does anyone actually read this thread? What I mean is, is it still worth me posting up here? Is my work of any interest to anyone, or should I just f*ck off down the zone pub and take up bickering as my new hobby? I get the feeling I'm talking to myself these days.

Nope, keep posting, I read this too, and understand fook all, but still a good read.

[DanThe]

Keep typing Geoff

[keri-WMS]

I hope to solve my past problems with regular QC visits and no payment until I have signed off on the job. Short of making the parts myself there's nothing more I can do.

Don't forget to take doughnut bribes for the guys on the shop floor....

[billgatese30]

I hope to solve my past problems with regular QC visits and no payment until I have signed off on the job.

The no payment bit in itself should do that, but frequent QC visits are certainly going to help reinforce your standards.

I also have a .pdf version of a solidworks bible somewhere that I got from Uwe. I'll see if I can find it (its not on my laptop) and I'll email it through or upload it if you like.

[gareth]

Did someone say my name?

I've got 81 pages of posts to read... err, this may take some time!

Welcome back Gareth, how's the blonde ?

Fanstistic, hence my slow reply!

The new design looks pretty strong to me

Oh and yes, I am reading, though i've not been on here since i last posted so keep it up!

[billgatese30]

so keep it up!

Sounds like your doing enough of that for the lot of us posting on the internet in the evening

[gareth]

[GeoffBob]

Nope, keep posting, I read this too, and understand fook all, but still a good read.

Cheers Rav

Keep typing Geoff

That I will, thanks Dan.

I hope to solve my past problems with regular QC visits and no payment until I have signed off on the job. Short of making the parts myself there's nothing more I can do.

Don't forget to take doughnut bribes for the guys on the shop floor....

Good Advice, will do.

I also have a .pdf version of a solidworks bible somewhere that I got from Uwe. I'll see if I can find it (its not on my laptop) and I'll email it through or upload it if you like.

Thanks Chris, that would be appreciated. I can PM you my e-mail, but if its bigger than 5MB I’d appreciate if you could upload it somewhere for me to download later.

The new design looks pretty strong to me

Oh and yes, I am reading, though i've not been on here since i last posted so keep it up!

Let’s hope so Gareth, I’m not sure I have the energy or the money to go through this again if the dog-rings fail a second time. It is definitely a better design though, I could kick myself for not doing it this way the first time. Live and learn, as they say.

so keep it up!

Sounds like your doing enough of that for the lot of us posting on the internet in the evening

Oh to be young and in love. The memories I have!

[GeoffBob]

Sorry, missed this one earlier:

I have no doubt many are readig this, with 99% of us learning and hence have little to add. I'm amazed how inefficient helical gear teeth are at full chat, based on your flywheel dyno figure being way too high!

Agreed, that figure was way too high for my gearbox, but probably realistic for helical gears. To drop a 100hp over a set of spur-gears is unlikely, especially when I could reach under the car (after the dyno test) and touch the gearbox without burning myself. But yes, helical cut gears are renowned for their inefficiency due to the axial directed force that results in additional friction. I have no doubt that replacing the helical gears with spur gears on a road car would result in a substantial fuel saving. The noise would, however, be unbearable. I also have no doubt that the only way I was able to achieve the wheel figure that I did is because of reduced losses in the gearbox. The losses in the diff are, of course, still as before.

Home designed gearbox. . . That's just bloody awesome!

Thanks Mate!

I use bohler for a lot of material at work, specifically, hardenable M340, 22CR Duplex and 25Cr Super Duplex.

Good to know, I may have questions in the future. M340 was actually recommended to me for my gears provided I was prepared to go through the process of induction hardening the gear teeth after through hardening the bulk material. I was tempted to go this route, but eventually opted for case hardened M120. Although the M340 would have made better gears, the hardening process is too detailed for the locals.

[GeoffBob]

And in the news today ...

My lump of M120 carbon steel has been delivered to ARMA Gears in Germiston. I'll be off down there either Monday or Tuesday to deliver the new drawings. Bohler e-mailed me a copy of the material certificate.

The manufacturing process will be as follows:

1) ARMA to machine the blanks from M120 Bohler steel, as supplied.
2) Send the blanks to Bohler Hardeners to have them normalised (annealed). This helps alleviate problems with the material distorting later on in the process.
3) Back to ARMA for detailed machining (hobbing of the gear teeth, milling the dog-teeth etc.)
4) Back to me to shrink fit the gears over the dog-rings and then weld the seam closed (I have special TIG rods on order from Bohler specifically for this job).
5) Back to Bohler Hardeners for case-hardening.
6) And finally back to ARMA for surface grinding and polishing.

My vernier gauge and I will be there to yay or nay each step of the process.

[keri-WMS]

Hardening welds - that's an interesting one (outside my experience), might get Gareth excited! Is there any risk of runout in the shaft as a result of the welding? (you'd miss any bend in the shaft if you were checking diameters etc with a vernier, you'd need a jig I'd have thought? Or run it on on a lathe to check it's true?)

Keep us updated, I'll be reading and maybe adding the odd daft comment!

[GeoffBob]

Hardening welds - that's an interesting one (outside my experience), might get Gareth excited!

All taken care of Keri Bohler M120 can be welded using Bohler DCMS-IG welding rods. The parts must be preheated to 300'C before welding and put back in the furnace after welding for controlled cooling. The hardening of the pieces is then permitted (or so I am told ).

Is there any risk of runout in the shaft as a result of the welding? (you'd miss any bend in the shaft if you were checking diameters etc with a vernier, you'd need a jig I'd have thought? Or run it on on a lathe to check it's true?)

No chance since each piece will be ground to the final dimensions after welding and hardening. Also, each gear will be shrunk fit to each dog-ring by heating the gear and cooling the dog-ring, and then dropping the gear over the ring. Once the gear and ring are at the same temperature the gear will be well and truly at one with the ring. You wouldn't be able to remove the gear from the ring even if you tried (not without breaking the gear). Welding the two together is, therefore, little else other than a precautionary measure. As it has been explained to me, any stresses that develop in the weld and its surrounds as the weld cools will be removed by the heat treatment process that follows, although it is unlikely that any stresses (symmetric or non-symmetric) will develop as a result of the controlled cooling (normalising) in the furnace post welding.

Watch this space to see me eat my words Gareth, your input would be valued if you know differently to the above.

[keri-WMS]

Good stuff - sounds like it's all under control, welding bits at 300c sounds like fun!

[gareth]

All i have to add to the above is: Don't forget to wear oven gloves over your welding gloves!
It all sounds about right to me (am am no expert in welding processes though)

Maybe work out a pattern to weld though. ie in sections, not just right round the gear, so the additional heat is distributed evenly while the two 'rings' are being joined. say 12 o'clock, 4 o'clock, 8 o'clock etc etc?

[GeoffBob]

All i have to add to the above is: Don't forget to wear oven gloves over your welding gloves!
It all sounds about right to me (am am no expert in welding processes though)

Maybe work out a pattern to weld though. ie in sections, not just right round the gear, so the additional heat is distributed evenly while the two 'rings' are being joined. say 12 o'clock, 4 o'clock, 8 o'clock etc etc?

Will do Gareth. Thanks for the advice.

[GeoffBob]

Well, I delivered my new drawings (dog-rings and gears) to Veron Pappas at ARMA gears today and all went extremely well. I have asked Veron to do nothing else (at this time) other than machine the blanks from the raw material for me. I also got to see my lump of M120 carbon-steel. Large and heavy is probably the best way to describe it. In all other respects rather mundane. Put it this way, if it were lying around in your shed you'd probably throw it away (if you could lift it), it certainly doesn't look at all worth what I paid for it.

I have to add that I am pleased with how Veron has bought into the new way of doing this job. He is more than happy to have me take care of the heat treatment and quality control process. I got the feeling that this is as much a learning process for him as for me, which is not to say that he doesn't know how to make gears, but rather that a job as detailed and involved as this is not the norm for his workshop. They survive, like many, on brute-force mining work, where every component is typically over engineered by a factor of 10. My small and delicate automotive gears are something a bit different to him, and is (I suspect) the reason why the other gear-makers I approached wouldn't touch the job. I do, however, get the feeling that he wants my project to succeed, and that this stems from the fact that he is himself a race-car-driver.

Other news is that the Bohler DCMS-IG TIG welding rods I ordered arrived today. These are the rods I will be using to weld the gears to the dog-rings before sending them for hardening. The rod datasheet is located here if anyone is interested. The chemical composition of the rod is similar, but not identical, to the Bohler M120 steel. Most notably, the rod contains a higher molybdenum content. I don’t foresee this as causing a problem.

[skipunda]

Love the R&D thats been discussed between members throughout this thread. Really nice!

[billgatese30]

I couldn't open the pdf for the welding rods Geoff, however, Molybdenum is typically added to welding rods when welding similar materials as it increases the toughness of the weld and makes it more ductile which is often very advisable when it is going to see further heat treatment (particularly if is going to be quenched, rather than tempered) so that the weld doesn't crack. I would imagine this is why they advised this rod seeing as you explained the further heat treatment steps. You may be able to tell this from any tensile/impact test results data on any of your data sheets or you may not, depending on the state of the material when sampled (rod material once it has been used in a joint etc rather than as virgin metal).

[DanThe]

Dont think you mentioned but - re the shrink fitting of the gears, what is the difference in the two dimensions before the heating/cooling etc?

[GeoffBob]

Love the R&D thats been discussed between members throughout this thread. Really nice!

Agreed. If I haven't said it already, I am extremely grateful to all zone members who have helped guide my project.

I couldn't open the pdf for the welding rods Geoff, however, Molybdenum is typically added to welding rods when welding similar materials as it increases the toughness of the weld and makes it more ductile which is often very advisable when it is going to see further heat treatment (particularly if is going to be quenched, rather than tempered) so that the weld doesn't crack.

Thanks Chris. What you say makes sense. I will of course be sure to cool the welded gears in a controlled manner in the furnace, also to avoid cracking. FYI, I have posted it up that data-sheet here as well if it is still inaccesible. File size is just under 1Mbyte.

Dont think you mentioned but - re the shrink fitting of the gears, what is the difference in the two dimensions before the heating/cooling etc?

0.1mm +/- 0.01mm on the diameter Dan. Steel has a coefficient of area expansion of around 0.000024 per degree Celsius. Conveniently (as it works out) a hole through a disc/ring of steel will expand the same as the plug that was cut from the disc/ring to make the hole. In other words, the area of the centre-hole through the centre of a gear will expand by a factor of 0.000024 per every degree of temperature increase. A gear with a centre-bore of say 50.00mm thus has an area of 1964mm^2. Raising the temperature of the gear by say 250’C will thus increase that area to 1975mm^2, which corresponds to a diameter of 50.15mm, which is sufficient to slide it over the dog-ring with an OD of 50.10mm.

[rrs]

Another one here just to say carry on journalling, I can't pretend to understand more than a small part of the reams of information in this thread but found it a fascinating and your patience and attention to detail is astounding.

[Jesus325iTouring]

WOW! Now this is an epic thread,I can't believe its been running for nearly 2 years and I never knew
I've not read all of it yet,what with my new addition to my house hold,but I can see several sleepless nights coming up so will be the perfect time!

Geoff,you are a hero,end of story.

[GeoffBob]

Another one here just to say carry on journalling, I can't pretend to understand more than a small part of the reams of information in this thread but found it a fascinating and your patience and attention to detail is astounding.

Thanks Mate, will do. Your comment is appreciated.

WOW! Now this is an epic thread,I can't believe its been running for nearly 2 years and I never knew
I've not read all of it yet,what with my new addition to my house hold,but I can see several sleepless nights coming up so will be the perfect time!

Geoff,you are a hero,end of story.

Good to meet a fellow fan of the R5 Jesus and congrats again on the newborn (Does that make God a grandfather). I think you had an honorary mention back on page 1 already, so someone must have known of your affinity for these cars. As B7 mentioned, not much of the original R5 left, and with good reason I guess. Building a car that I dreamt of from cars that I loved is something I just couldn’t resist trying my hand at.

Like a few others, I have only just discovered this thanks to Jesus' R5 thread... (have never ventured into motorsport/trackday forum.. ) Just consumed 3 hours of my life reading it

All I can say is EPIC!! Keep it coming.. (subscribed)

All this talk about metals, hardening quenching etc takes me back to a distant previous life where I was a metallurgist (circa 1972), designing all sorts of metals for various purposes... however, soon got tired of being cooped up in a lab so broke free and got out into the fresh air

Welcome to my thread Will, pleased to heave you on board and thanks for taking the time to read through. I have been following some of your threads elsewhere on the Zone and believe that we have a common appreciation of Toyota gearboxes? Please feel free to contribute any suggestions on materials processing if you feel so inclined. This whole thread is a learning process for me and I welcome inputs/suggestions.

[GeoffBob]

Well, I must have been feeling generous today as I gave away my old Toyota Hilux pick-up truck. Nearly 30 years old it is, and belonged to my late Dad. What the picture below doesn't show is that the load-box is badly rusted through from all the garden rubbish that was left to rot on the back before being hauled to the tip. God knows how many miles it did. Only has 5 s digits on the clock and I lost count of how many times they ticked over. Was on its second engine and even that was on its last legs. Didn't smoke excessively, but still used a fair bit of oil during it's last few years. Truth is, she lost her pride of place (not to mention her covered parking) to the new Hilux. Since retiring her I decided to strip her down and do a rebuild, but I never did get around to it, and so she just stood and collected rust and dust, and that's no way for my Dad's old wheels to go. Anyway, a mate of mine has had a hard time of it of late. He had to sell his Hilux double-cab when his second was born premature and the bills mounted. He's brilliant with cars and especially good with Toyota's, so I gave it to him. If anyone can bring the old Hilux back to her former glory he can. I considered fixing her up to sell her but the money I would have got back would have been less than the cost of getting her to sellable condition, so I figure giving her away is a fair deal (no scrapage scheme down here) and I really don’t want to see her on the tip. I’m just wondering how much I am going to regret this when I wake up sober tomorrow? So long old Hilux.