Johny's Electric Vogue

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Post by StudentEV » Mon, 27 May 2013, 20:13

Ah I see, so there's coupler and the joint. Yeah I also can't imagine anything being wrong with the coupler so I guess I mean the joint.

What I was thinking was something with less give, similar to a lovejoy or even something like this:

Image

Though I'm fairly sure this means you'd need to re mount the motor to have a fixed shaft and perfect angle from motor to diff, with rubber mounts so it has some give, not an ideal solution.

Also, the joint you have is the one used on most driveshafts, right? So it's unlikely to be the cause, but maybe your particular joints are busted or something? My thought is that if there is too much give it might start to shake at high speeds, which is counter-intuitive because it's more likely to vibrate/be clunky at low speeds if there is. I guess the balancing should show the results.

I bet you are about sick of the problem and just keen to keep driving the car!
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Post by weber » Mon, 27 May 2013, 20:34

There is a worry that the grub screws pressing on the key might be causing a small parallel misalignment between motor shaft and coupler, but I assume you measured runout on the coupler flange when attached to the motor?

Could it be misalignment between the coupler and the yoke. There are of course two kinds of misalignment, angular and parallel offset. Since the coupler is turned from a single piece it's hard to imagine its flange would not be at right angles to its shaft hole. However you could use the dial gauge or chinagraph pencil arranged axially to check this, with the yoke detached. And one assumes the same of the yoke flange. So that makes angular misalignment seem unlikely. But what aligns the yoke flange with the coupler flange? I assume there is a turned projection from the yoke flange which is a location fit in the turned hole in the coupler flange. Can you scrape the paint off the outside edge of the yoke flange and check its runout when it's bolted to the coupler on the motor?
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Post by Johny » Mon, 27 May 2013, 20:53

weber wrote: There is a worry that the grub screws pressing on the key might be causing a small parallel misalignment between motor shaft and coupler, but I assume you measured runout on the coupler flange when attached to the motor?
I checked the coupler face and flange outer edge (just 'cause I could) with the dial gauge when I had it set up. The coupler was turned up in a lathe - pretty simple job. I also would have seen runout in the slip-yoke shaft outer if any of that had been out of whack. I agree that the grub screws could push it out, but again that would have shown up on the dial gauge.

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Post by Johny » Thu, 06 Jun 2013, 17:47

This post was an exact copy of my blog posting today until I edited the blog to improve clarity slightly.
---------------------------------------------------
Reading back over the blog when I first installed the tail shaft I kind of skipped over some of the messing around I had to do to get it fitted.

One of the reasons I didn't blog all of it was that it seemed like a criticism of the guys that made the coupler and tailshaft and the problems were sorted out pretty quickly - but maybe they weren't after all.

Here is the whole story.

The first ever time I installed the tailshaft, it took me a longer time than I would have thought possible to realise that the four bolts that hold the front tailshaft flange to the motor coupler didn't actually line up. The holes in the motor coupler, while being the correct Pitch Circle Diameter (PCD), were arranged equidistantly around the circle. The universal joint flange on the front of the tailshaft was arranged as a rectangle. This is pretty standard for universal joint (UJ) flanges - at least with cars that I have played with.

This picture isn't of mine but shows what I mean. The two holes on the right are closer than the two holes across the top.
Image
That being the case, the first drive of the Vogue had the front of the tailshaft being held to the coupler with two M8 bolts 180 degrees from each other as all four bolts could not be fitted.

Obviously I wasn't going to leave it that way, so before the second drive I removed the coupler and tailshaft and took them back to the guys that made them and they added some holes and tapped them out to M10. (The original M8 tapped holes were left alone).

When I got it all back and managed to find some fine thread M10 bolts of the correct length, I took another huge period of time under the car before I decoded that there was no way I could get these standard hex bolts in past the universal joint cup holder (the bits jutting out). So a day or two later I bought some M10 Allen head machine screws.

Again I messed around for an hour or so trying to get these in with no success. They fitted through the tailshaft (UJ) flange OK but would not all thread into the motor coupler when I offered it up. At some point I realised that the tailshaft flange holes were imperial 3/8 inch - that's 9.525mm.

So I pulled the tailshaft out completely, held the tailshaft as best I could in my workmate, and hand drilled the holes out to 10mm - the biggest drill I had. I cleaned up the facing side of the flange with a 1/2 inch drill bit and ensured there were no burrs.

Once the holes were drilled out, I could almost get all the bolts in by hand. Importantly I could now place the tailshaft flange on the coupler flange, mate the spigots up (the 60mm diameter sections used to correctly locate the flanges) and insert and tighten the bolts up. There was always one or two bolts that I had to pull in with the Allen key the last 6mm or so but it all looked correct.

I explained this to the guys that made ther tailshaft and coupler but they weren't too concerned and have had the tailshaft back twice since then.

So now we are up to this week.

When I picked up the tailshaft on Manday night, it was explained that the balance was fine and they hadn't changed much. It fitted it Tuesday night and it behaved pretty much the same way as before. However, this time I had arranged a system were I could control the motor speed while lying under the car so could have a "play" without having to ask someone else for help controlling the speed. What I found was, even though earlier tests showed the front of the tailshaft rotating without excessive runout, that was not the case on the slip yoke. The UJ flange rotated true but the inner part of the slip yoke did not.

I whittled a chunk of wood and tried moving the UJs in their housings (in the direction that would remove the runout) - no give at all.

For some reason I decided to remove the four M10 bolts and track down the two M8 bolts and washers that I had used on the first drive.

Once I had the tailshaft bolted to the coupler with only two M8 bolts, there was an immediate and substantial improvement. I made a further slight improvement by loosening the bolts and using the tiny bit of play in the spigot to move the mating flanges in a direction that would help.

That's how I drove it on today - a lot better. Not perfect yet, but better.

It appears that there is a concentricity problem in the front slip-yoke and UJ combination.

If the tailshaft is being held by the front flange during balancing I would think it would be balanced out.

So we know what it is - now to fix it completely.

A note here. I measured runout months ago and concluded that the tailshaft was fine. The closest I can normally get to the front of the tailshaft is about 300mm from the slip yoke, and it's a lot better at that point. I've got a lot braver with rotating machinery (while still being careful) over the time. A whole lot of factors have conspired to create this problem and make it hard to track down. My inexperience hasn't helped.
Last edited by Johny on Thu, 06 Jun 2013, 12:10, edited 1 time in total.

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Post by weber » Thu, 06 Jun 2013, 20:06

Hi Johny. This is all good additional information, but I'm a little confused. Some of it seems to contradict other parts of it, and/or seems to contradict some things in your other recent posts.

First some terminology to make sure we can understand each other. A single universal joint (UJ) has two yokes, each of which has two ears (your cup holders). In this case, at the front end of the tailshaft, the input yoke is a flanged yoke and the output yoke is a slip yoke.

We seem to have it narrowed down to one (or more) of the following 4 things:
(a) Rotational imbalance in the flanged yoke.
(b) Rotational imbalance in the slip yoke.
(c) Misalignment (eccentricity) between the flanged yoke and the slip yoke.
(d) Misalignment (eccentricity) between the motor coupler and the flanged yoke.

(a) and (b) would seem to have been ruled out by the whole UJ assembly having just been balanced along with the shaft, however it seems possible to me that a slight imbalance could be cancelled out by a slight eccentricity. However this seems very unlikely since presumably this pair of yokes had a successful career in some other vehicle before coming to you, except maybe if one yoke got rotated 180 degrees relative to the other when a new center (the cross-shaped thing with its 4 bearings) was installed. A previous successful career would also suggest that (c) (eccentricity between yokes) is very unlikely, unless there is significant play between the circlips.

In regard to (d) (eccentricity between coupler and yoke) I asked a question about how that was located in my previous post. You seem to have answered that now by implying that although it is supposed to be located by the 60 mm spigot and socket, the socket was made too large in the coupler and it is being defacto located by the 10 mm bolts in their tight-fitting holes and this is causing (d). Is that correct?

I suggested measuring runout on the yoke flange as opposed to the coupler flange. You wrote:
Johny wrote:I also would have seen runout in the slip-yoke shaft outer if any of that had been out of whack.
This is not the same as measuring runout on the yoke flange, due to the possibility of (c) but it did imply that you had measured runout on the slip yoke shaft outer and found none. But now you write:
What I found was, even though earlier tests showed the front of the tailshaft rotating without excessive runout, that was not the case on the slip yoke.
Please explain the apparent contradiction here.
The UJ flange rotated true but the inner part of the slip yoke did not.
What do you mean here by "the inner part of the slip yoke"?
I whittled a chunk of wood and tried moving the UJs in their housings (in the direction that would remove the runout) - no give at all.
So this is the operation jonescg suggested a while ago. Do they fail to move because the circlips are precise (as they should be) or because they are rusted or otherwise siezed in place. i.e. do they move if you remove the circlips?
Once I had the tailshaft bolted to the coupler with only two M8 bolts, there was an immediate and substantial improvement. I made a further slight improvement by loosening the bolts and using the tiny bit of play in the spigot to move the mating flanges in a direction that would help.
This implies (d), eccentricity between coupler and yoke.
So we know what it is
We do? What is it?
Last edited by weber on Thu, 06 Jun 2013, 10:11, edited 1 time in total.
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Post by Johny » Thu, 06 Jun 2013, 20:15

Whew! I tried pretty hard to sum it up and fill in the gaps I had left out but I see that I have still glossed over some parts.

All parts of the tailshaft are brand new.

My conclusion is that there is eccentricity between the yoke and the UJ flange. I can slightly alter this using the available 0.3mm or less of movement in the spigot alignment.

The 10mm bolts are pulling the spigot alignment off just a tad but that it not the primary problem - it may not even be a problem. Using the 8mm bolts in the larger holes let me "play" with the alignment slightly.

The "outer" of the slip yoke is not machined hence I referred to the part of the slip yoke attached to the tailshaft as the inner. I was warned not to bother about the slip-yoke outer by the tailshaft makers.

I do not believe that they balanced the tailshaft by driving, or coupling up to, the slip-yoke end of the tailshaft. So I think, while it's balancexd, when I drive via the flange, the whole tailshaft is eccentric. By fiddling with whatever lattitude I get with the front flange I can change it.

It's exciting because this is the first time I have been able to make ANY difference.


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Post by Johny » Thu, 06 Jun 2013, 20:20

weber wrote:We do? What is it?
It's the tailshaft. I didn't pin it down any tighter than that - it's the first solid fact.
BTW I don't pretend that I haven't been confusing in my reporting along the way but rest assured it wasn't malice - just confusion.

Edit: When I want to type rest, I type reset. Perils of the job...
Last edited by Johny on Thu, 06 Jun 2013, 12:11, edited 1 time in total.

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Post by Johny » Thu, 06 Jun 2013, 21:58

weber wrote:
Johny wrote:I whittled a chunk of wood and tried moving the UJs in their housings (in the direction that would remove the runout) - no give at all.
So this is the operation jonescg suggested a while ago. Do they fail to move because the circlips are precise (as they should be) or because they are rusted or otherwise siezed in place. i.e. do they move if you remove the circlips?
Sorry I should have done a point by point reply. Anyway, no they are nice and secure.

I have edited my post on the blog to improve clarity a little bit.
Thanks for the prompting and clarification weber.

Edit: Removed stutter
Last edited by Johny on Thu, 06 Jun 2013, 12:08, edited 1 time in total.

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Post by acmotor » Fri, 07 Jun 2013, 07:10

Johny wrote: .....
All parts of the tailshaft are brand new.....


Just some are slightly butchered. Image

Great news that you are making progress though.

I do read that folk have suggested the very problems you are uncovering now and were told that it is all correct. I also read that the 'tailshaft masters' have let you down. Clearly you need to be ultra critical of the detail.

Like a good crime story, the more questions are asked the more you let on. Image

On the home run now.
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Post by Johny » Fri, 07 Jun 2013, 15:23

acmotor wrote:
Johny wrote: .....
All parts of the tailshaft are brand new.....


Just some are slightly butchered. Image
Not quite. The front flange holes do need drilling out further and I haven't done that for fear of "butchering" them. I will leave that to someone else to do with better jigging.
I do read that folk have suggested the very problems you are uncovering now and were told that it is all correct.
...
...
Clearly you need to be ultra critical of the detail.
When I read back over everything that I still maintain it is correct but contradictory in places - I agree. Still more to know. Detail? The 10mm bolts weight 27 grams each - never posted that "detail".
... I also read that the 'tailshaft masters' have let you down.
Hardly. We still haven't determined to true cause of the problem and they have never turned me away. Jeff has already lined up Saturday week to briung the portable balancing gear out to my place and "get to the bottom of it" - at no cost.
Like a good crime story, the more questions are asked the more you let on. Image
I still have to reconcile why the flanges look aligned and measure so, but changing the bolts to smaller ones have made such a big difference.

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Post by acmotor » Fri, 07 Jun 2013, 18:16

No worries Johny, I'm just being devil's advocate.

My thought is that a tail shaft flange to flange including unis and spline presented to a balancer should be balanced flange to flange. Simple me for expecting the obvious. Image

I'm not certain the question of the uni caps position was satisfactorly resolved ? Can you examine that one again ? You said firm or tight.
Johny wrote: Jeff has already lined up Saturday week to briung the portable balancing gear out to my place and "get to the bottom of it" - at no cost.


That will be good ! It always beets balancing just the parts.

Your experience with the vibration and eventual remedy will be valuable to all of us.

Right now though you probably curse why this part of the conversion has taken so much effort.
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Post by Johny » Fri, 07 Jun 2013, 20:10

acmotor wrote:My thought is that a tail shaft flange to flange including unis and spline presented to a balancer should be balanced flange to flange. Simple me for expecting the obvious. Image
I spoke to him again today and he swears on his Mother's grave (she's not dead yet) that they DO do (do do?) it that way.
I'm not certain the question of the uni caps position was satisfactorly resolved ? Can you examine that one again ? You said firm or tight.
They are fine. The Unis drop under the weight of the flange but aren't loose. The caps have no slack.
Johny wrote: Jeff has already lined up Saturday week to briung the portable balancing gear out to my place and "get to the bottom of it" - at no cost.


That will be good ! It always beets balancing just the parts.
Yes. I was going to cancel it but based on today's converstion with him we'll go ahead (at this stage). Not this weekend - the next.
Your experience with the vibration and eventual remedy will be valuable to all of us.
Yes. I apologise if I'm getting testy.
Right now though you probably curse why this part of the conversion has taken so much effort.
!@#$%^&^

On a good note. We just went to lunch at the Wheelers Hill Hotel - big hill. At the top of the hill coming back down (heading east along Ferntree Gully Rd) I had 45kM remaining range. Rolling in the driveway at work I had 50.4kM remaining range. Unfortunately I lost 10 going uo though.

I also climbed my worst nightmare gradient just outside the pub with two passengers coming back - Hotel driveway into Jells Rd just North of Ferntree Gully Rd then heading South for a few tens of meters. (they helped coming down the big hill too as I only had one going up).

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Post by acmotor » Fri, 07 Jun 2013, 21:07

Good regen (DC files eat your heart out !).

( the p is next to the o, at least on my KB ) Image

Re UJ needle bearing caps, sorry to labour on that point but the caps are press fit with usually a circlip to stop them comming out.
If they are not pressed in evenly or circlip position does not match particular UJ body there is potential for off centre situation. Also, if the spider has any play radially in the caps this can cause problems.
Johny, It might just be me but it is not clear that this has been checked from you descriptions. Weber was also flagging these caps.

IFFFFFF the assembly was balanced as a whole then this would be less of an issue but radial movement may still occur as the balance RPM would need to be known.

The balancing machine that must have a bearing face at each end to bolt the UJ flange to ? Can we see some pics ?

If this is all hastling you then take it as a further incentive to put the problem to bed. (as if you need one). Yes, the frustration is showing ! Image
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Post by Johny » Fri, 07 Jun 2013, 21:21

acmotor wrote:Re UJ needle bearing caps, sorry to labour on that point...
I checked them quite thoroughly when I had the tailshaft out last. I have rebuilt UJs in tailshafts before (which why I don't choose to now) and they are good. I can not detect any lateral movement in the UJ body (centre X) and yes the cups are held with circlips which are properly seated and hard up against the cups. I agree that this is a likely area for the problem which is why I attacked them with a wooden drift.
The balancing machine that must have a bearing face at each end to bolt the UJ flange to ? Can we see some pics ?
If I end up back there I promise to take pics of the machine flange holding mechanism. I always just drop off the tailshaft and pick it up a few days later. No while-you-wait. It has to be scheduled for the machine.
If this is all hastling you then take it as a further incentive to put the problem to bed. (as if you need one). Yes, the frustration is showing ! Image
Thanks Image

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Post by TooQik » Fri, 07 Jun 2013, 23:41

Hi Johny, I've been reading through your driveline vibration issues to see if I could spot any obvious cause and read the following statement you wrote back in March...
Johny wrote:Last night I removed the driveshaft and ran the motor with coupler still attached. The vibration kicked in at 2000 RPM (50 km/h), faded a bit as the speed increased then kicked in again at 3800-4000 RPM (100 km/h). I removed the coupler and ran it again with exactly the same result.
From your above post it is evident that the problem lies somewhere in the front so any more tailshaft balancing/checks etc would be chasing ghosts. I would be checking all mounting points, bolts and nuts for the motor cradle itself. I had a similiar vibration/knock once when a gearbox crossmember bolt worked loose. A quick tightening of the offending bolt and problem was gone.

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Post by Johny » Sat, 08 Jun 2013, 00:01

It was shortly after that I removed the eMotor and had the rotor balanced. The blog has more details. The vibration label on the right of the page helps navigation.

Oh if it were just a loose bolt perchance...

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Post by TooQik » Sat, 08 Jun 2013, 00:10

I did read about the rotor being balanced but you didn't mention (or I missed) whether you actually ran the motor up again without the drive shaft attached to determine whether the vibration was still evident. If you did and it was gone, then yes vibration is definitely further downstream.
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Post by weber » Sat, 08 Jun 2013, 05:47

Johny wrote:It's the tailshaft. I didn't pin it down any tighter than that - it's the first solid fact.
BTW I don't pretend that I haven't been confusing in my reporting along the way but rest assured it wasn't malice - just confusion.

Edit: When I want to type rest, I type reset. Perils of the job...

I certainly never imagined any malice, reset assured. Image

But I don't see why it has to be in the tail shaft. Why couldn't it be misalignment between the motor shaft and the tailshaft? You describe it as improving when you changed that alignment.
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Post by weber » Mon, 10 Jun 2013, 18:18

Johny wrote:The front flange holes do need drilling out further and I haven't done that for fear of "butchering" them.
Call me a butcher, but I'd just clamp the flange in a vice (with soft jaws) and [Edit: Here I gratuitously insert the word "hack" so that coulomb's later elliptical construction is valid.] use a 10 mm bit in a hand-held drill and wobble it around a few degrees off normal to enlarge the hole. The formula is

D = d/cos(theta)
where D is the new hole diameter,
d is the drill bit diameter and
theta is the angle of the wobble.

And therefore theta = acos(d/D)
e.g. if we want an approximately 10.6 mm hole we wobble our 10 mm drill out to roughly acos(10/10.6) = 19 degrees off normal.

But as I read it, you also have a problem whereby the socket in the motor coupling flange is too big for the spigot of the UJ flange, and so doesn't serve to locate them relative to each other with sufficient accuracy. You mention 0.3 mm of play. It probably should be less than 0.05 mm.

I also read that this is a blessing in disguise, because you get less vibration when you push the spigot over against one particular side of the socket. Does that beneficial direction happen to be moving the centre away from the grub screws?

What happens if you unbolt the UJ flange from the motor coupler flange, rotate one of them 180 degrees and bolt them back together? Does the beneficial direction of offset stay the same relative to the motor coupler (e.g. still away from the grub screws) or does the beneficial direction of offset stay the same relative to the UJ flange (e.g. now towards the grub screws)? This will tell you whether the fault lies with the motor coupler or the tailshaft.

In any case I'd mark the two flanges so they always go together the same way. In particular I'd mark them at the side of the coupler flange that the UJ is best pushed towards. Then call me a butcher again, but I'd put the coupler in a vice and use a hammer to peen near the edge of the socket at two points about 120 degrees either side of the aforementioned mark, until it was a tight fit on the spigot of the UJ flange.
Last edited by weber on Mon, 10 Jun 2013, 15:48, edited 1 time in total.
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Post by Renard » Mon, 10 Jun 2013, 19:59

weber wrote:
Johny wrote:The front flange holes do need drilling out further and I haven't done that for fear of "butchering" them.
Call me a butcher, but I'd just clamp the flange in a vice (with soft jaws) and use a 10 mm bit in a hand-held drill and wobble it around a few degrees off normal to enlarge the hole. The formula is

D = d/cos(theta)
where D is the new hole diameter,
d is the drill bit diameter and
theta is the angle of the wobble.

And therefore theta = acos(d/D)
e.g. if we want an approximately 10.6 mm hole we wobble our 10 mm drill out to roughly acos(10/10.6) = 19 degrees off normal.

I'm sorry to say call-me-a-butcher would be a good epithet, if you follow that formula. But since it's a wet and grey afternoon here, and the shed looks cold, I'll point out that the angle you specify should depend on the thickness of the material.
I suggest:
D/t = d/t cos(theta) + tan(theta)
where t is the material thickness.
For your figures of 10, 10.6 and 10mm thickness, theta = 4deg.

But even that formula supposes that you achieve a conical hole; in practice the end of the drill bit will simultaneously widen out the bottom half of the hole, so one should take 0.5 x theta. Difficult to manage in practice.

(Sorry Johny.)
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Post by Johny » Mon, 10 Jun 2013, 20:17

Just relax guys - I'll buy a 10.5mm drill. It's difficult enough as it is using a hard drill to do this.

Weber, when I say there is some movement in the spigot, I couldn't see the movement, just hear it when I rattled the loosened flange side to side.
Earlier when I said:
"I made a further slight improvement by loosening the bolts and using the tiny bit of play in the spigot to move the mating flanges in a direction that would help."
It was so slight that I should not have mentioned it. Without an actual method of measuring vibration it gets a little hard to pick slight improvements once that big improvement was made. I haven't had time for any car stuff this weekend (other half put back out).

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Johny's Electric Vogue

Post by weber » Mon, 10 Jun 2013, 21:06

Renard wrote:I'm sorry to say call-me-a-butcher would be a good epithet, if you follow that formula. But since it's a wet and grey afternoon here, and the shed looks cold, I'll point out that the angle you specify should depend on the thickness of the material.
Image

Now what do you say?

Interestingly, although I had practiced this for decades, I was only forced to work out the trigonometry recently, due to someone whose intuition caused them to make the opposite mistake to yours. They thought the narrowest part would not be enlarged at all.
Difficult to manage in practice.
The purpose is only to produce a clearance hole, so the diameter, and hence the wobble angle, is not critical. Although a possible issue in this case is imbalance if you remove significantly more material from one hole than the other.

If the flange really is 10 mm thick you would probably be better off just buying an 11 mm or 7/16" (11.1 mm) bit and drilling straight. I just wanted an excuse to post that formula.
[Edit: 10.5 mm would be fine. I hadn't read that when I posted the above. I was just going for a readily available size.]
Last edited by weber on Mon, 10 Jun 2013, 11:15, edited 1 time in total.
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Johny's Electric Vogue

Post by weber » Mon, 10 Jun 2013, 21:42

Johny wrote:Earlier when I said:
"I made a further slight improvement by loosening the bolts and using the tiny bit of play in the spigot to move the mating flanges in a direction that would help."
It was so slight that I should not have mentioned it. Without an actual method of measuring vibration it gets a little hard to pick slight improvements once that big improvement was made. I haven't had time for any car stuff this weekend (other half put back out).
Sorry to hear about your wife's back problem.

When you wrote:
For some reason I decided to remove the four M10 bolts and track down the two M8 bolts and washers that I had used on the first drive.

Once I had the tailshaft bolted to the coupler with only two M8 bolts, there was an immediate and substantial improvement.
I assumed this substantial improvement was also due to a change in alignment between the two flanges. I assumed the tight 10 mm holes were pulling it into a bad alignment that was being allowed by the slop between the spigot and socket.

So what's your theory as to why this caused a substantial improvement?
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Johny's Electric Vogue

Post by Johny » Mon, 10 Jun 2013, 21:58

There is a theory that I was warping the 1/4 (or 5/16) inch thick flange on the UJ when I tightened down the 10mm bolts.
All along I have said that the runout appeared to be fine on both the motor coupler and the UJ flange. There is something about tightening up those 10mm bolts when the holes were not big enough for clearance and the coupler holes were not in perfect alignment. Not sure what though.

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Johny's Electric Vogue

Post by Renard » Mon, 10 Jun 2013, 22:06

weber wrote:

Now what do you say?


Nice diagram.
I was calculating the maximum hole diameter. You've calculated the minimum.
Renard

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