# Taper Lock Bushing Info



## madderscience (Jun 28, 2008)

The taperlock coupling that was made for my car was a 'wobbler' as well but at least it was made from steel as opposed to cast iron.

A few minutes on a lathe to turn down the face of the coupling (against which the flywheel would mount) fixed it for me. Seems to me the problem is for the normal usage of a taperlock hub that surface isn't required to be all that precise, so the manufacturers don't try.


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## Pb Cruiser (Oct 29, 2007)

On the subject of taper lock bushings I'm getting ready to have my motor shaft turned down to 1.00". This will enable me to use a 1008 bushing with an ID of 1". I need to use the smallest bushing possible because the bolt circle diameter on my Geo flywheel is 52mm and the OD of the hub that I have machined cannot be any larger than 68mm. Will using the 1008 bushing provide the necessary strength that is needed in this area? The flywheel is attached with 6 10mm bolts and I don't want to run the risk of the hub splitting. I'm considering using a standard taper lock sprocket and having it machined to fit the flywheel; this in order to cut costs. Is this a good idea as long as the sprocket is steel instead of cast iron? Also what is the diameter of the small taper end of a 1008 bushing?


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## Carroll_1 (Dec 18, 2007)

Pb Cruiser said:


> On the subject of taper lock bushings I'm getting ready to have my motor shaft turned down to 1.00". This will enable me to use a 1008 bushing with an ID of 1". I need to use the smallest bushing possible because the bolt circle diameter on my Geo flywheel is 52mm and the OD of the hub that I have machined cannot be any larger than 68mm. Will using the 1008 bushing provide the necessary strength that is needed in this area? The flywheel is attached with 6 10mm bolts and I don't want to run the risk of the hub splitting. I'm considering using a standard taper lock sprocket and having it machined to fit the flywheel; this in order to cut costs. Is this a good idea as long as the sprocket is steel instead of cast iron? Also what is the diameter of the small taper end of a 1008 bushing?


Sorry, I don't have any experience with the 1008 bushings. We've been using QD (quick disconnect) flanged bushings and I've just been calling them taper lock bushings. My bad. I would assume the same precautions would apply to the 1008 bushing. Tighten evenly and in an orderly sequence, and test for runout before installing. I don't have specs available for the diameter, but it looks like they use an 8 degree taper. I agree, a steel coupler would definitely be better than a cast iron piece.

Craig


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## Pb Cruiser (Oct 29, 2007)

Thankx for the info. Oddly enough I sat down with a machinist today to discuss options and we agreed that a flanged QD bushing would be the least expensive option and also the easiest to fabricate. He's also going to turn down the armature shaft for me to eliminate the splines, cut it to length and mill a keyway. He asked me " You're building an electric car, aren't you"? Drat, he's onto me. More to share later. Terry.


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## Thaniel (May 25, 2008)

So would do you recommend thread locking the taperlock retaining screws in? I'm using a taperlock (standard style not QD) and can not think of why I would not thread lock the screws in. However I've not had any experience before with a taperlocks.

Pb Cruiser 1008 has a fairly low torque rating. I don't have the numbers handy. Sounds like your going with a QD style now though anyway. (I'm using a 1610 on mine but my bolt pattern is a bit larger in dia)


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## Carroll_1 (Dec 18, 2007)

I don't see any problem using threadlocker, but I would use a removable product. I use blue Loctite Removable Thread Locker 242 on all of my coupler locking bolts and/or setscrews.


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## JRP3 (Mar 7, 2008)

Have you continued your testing on taper lock and set screw couplers?
I'm currently debating what to use.


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## Carroll_1 (Dec 18, 2007)

Yes we are continuing our testing. Here's my opinion based on what we've seen so far. Remember though, just my opinion.

We've produced both clutch style and clutchless style couplers built both with taper lock adapters and built as set screw type. Either style can be produced to do an adequate job. The key factor seems to be manufacturing accuracy. I'll tackle the taper locks first.

As I said earlier, we've used the QD style taper lock adapter for our taper lock designs. We've encountered two main problems: 1) we've had some difficulty receiving consistent product. There are a number of mfgs, styles, and materials of this product. Some versions have a slight dimensional variation, some have significant variation and performance. We're trying to produce repeatability during multiple part runs and the variations have been real productivity killers. 2) machining the mating taper on our coupler halves has proven to be very demanding. Although we utilize a CNC turning center (Haas SL-20), actually machining a perfectly round and true coupler with an accurate taper matched to a true centerline, with accurate threaded flywheel bolt holes (or a splined clutch hub) and holding a +/- .0005" tolerance is a challenge. The bottom line is, they are hard to produce, must be very carefully installed, and even more carefully tested prior to assembly. If you get all that correct, they are a great solution.

Over the past few weeks we've manufactured several setscrew style coupler designs. Once we've documented the exact required mounting location, we either design the coupler to positively locate against the motor's drive end inner bearing race, or if the design requires it, we produce a seperate spacer ring to slide over the motor shaft first, to locate the coupler. Manufacturing an accurate set screw style coupler still requires sound machining methods, but is easier than machining a taper. A good set screw style coupler is all about the shaft bore. We try to hold the shaft to bore clearance from .0003" to .0005". (that's three ten-thousandths to five ten-thousandths of an inch) Any tighter is pushing an interference fit, any looser is well, just looser. It can be cut close with either an indexable drill or a boring bar, but the final sizing has to be done with a reamer. Pretty standard machining.

So back to my opinion. I think both styles will work great if care and attention is paid to manufacturing methods as well as installation. I know that the most carefully machined taper lock can easily become a wobbler if it isn't installed very carefully and then tested. I also know that an "easy to install" setscrew style coupler can possibly fail if it's not machined to exacting tolerances. Personally, I think the setscrew style coupler is simpler, and that's mostly what we've been producing lately.

One last thing. A clutchless style coupler can stand to be a little looser toleranced than a clutch style coupler. The clutchless style is less than 3-1/2" diameter and weighs about 4 lbs. If it's a little out of round or has some face runout, it generally won't be a big deal. As long as it's balanced pretty well it won't vibrate. On the other hand, a clutch style coupler needs to be very accuate. If you get a few thousandths runout on the face, by the time you bolt the big old heavy flywheel and pressure plate back on, the runout will be greatly increased. It won't take long to feel a wobbly out-of balance flywheel. 

Hope some of this made sense.

Craig


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## JRP3 (Mar 7, 2008)

I only see the taper lock couplers on your site. Are you selling the setscrew type? I assume they would be cheaper since they are easier to make?


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## Carroll_1 (Dec 18, 2007)

I haven't listed any of the new set screw couplers we've produced as we haven't had machine time to run more product. We've invested in several new coupler designs and produced prototypes of them to add to our library, but firing up our CNC equipment for additional one off pieces just isn't cost effective. We've tried to build for what we believe to be popular models, but picking the right models has been a crap shoot so far and there hasn't been a demonstrated "most popular". I'm also being very cautious to not list products that we can't produce in just a few weeks. In a perfect world I'd prefer to only list products we acutally have on the shelf as I feel that credability in this industry is vital. I've seen too many cases of flashy announcements followed by a failure to produce. At this point my business is only a few months old and we're working hard to improve a number of areas.

Although the set screw couplers are easier to machine, we do have the extra secondary operations of broaching the keyway and drilling/tapping the setscrew location, so we have been selling them for the same price.

Craig


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