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How to 'drill' a splined hole...


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This is a useful technique if you want to make a spline (male or female) but don't have a broach to cut it properly.

It only works for things with even numbers of splines - but is still very useful as most splines seem to have even numbers of 'teeth'.

Although not as strong as a proper spline - they work surprisingly well. I have used this to connect the motor on my electric Freelander to the gearbox and that has to handle 400Nm.

First drill a ring of holes (half the number as the number of splines on the original). You have to settle for half the number of teeth because the 'drilled' splines are not pointy enough.


Then drill out the middle:


In the case of a winch motor, you need 10 x 4mm holes around a 14.7mm diameter then drill the middle out to 14.7mm.

Although I've used a mill in this case because I'm drilling 50mm deep holes very close together and needed to be as accurate as I can - I have done this using a pillar drill, marking out the centres with a pair of dividers (compasses).

Can you guess what I'm making? I actually mentioned the idea in another thread wondering if it would work - and the answer is, Yup it works brilliantly!


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This is what it's all about!

Although this is certainly not the first twin-motor conversion by joining two motors end to end, all the previous rely on cutting a spline or a keyway in the rear end of the first motor. This means it's not a standard, off the shelf motor. When it catches fire half way through a challenge - you're shagged unless you brought your Mill, shaper or spline broach with you to spline the back of a replacement motor.

This allows both motors to be absolutely standard and off the shelf.

It's an intrinsic part of the next thing I've been making:


This is a geared up, multi motor adapter for a Tds winch. As you can see there is space above the drum for a second motor behind the first one. The winch is 15cm narrower than a standard Tds - so can have a longer drum. The fact that the motor has been moved to the opposite end means the drum can contain a Delta-Tek style freespool.

As it stands, the winch could have one, two, three or even four motors! With a freespool, you would be limited to three however! ;)

As a single motor winch, it allows you to fir a freespool and a Bow2 motor (probably the best motor on the market at the moment) which is unfortunately too long to fit between the chassis rails of a LR on a standard TDs.

While I'm probably not the first person to think of this - I am probably the first person to do it!


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Is it compatible with Bowyer's air freespool?

With a delta-tek style freespool I presure you could still get 4 motors on it?

Just for giggles, could you put 5 motors on it, with the fifth in the stock TDS position? :P

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This may answer your question:

Well done Steve - Have an O Level!

The aluminium housing has a spline cut in both sides so you could mount one motor poking down through the surface of the Workmate. The only trouble with this is that it partially obscures your headlight if mounted on the front. A third motor can be added on the back of the one pictured with the adapter I've been machining this weekend.

The fourth would mount where the standard Tds motor goes - although this precludes a DeltaTek style freespool.

I suppose if it were mounted on the front, because it's narrower than standard, you could move the whole thing to the left so it doesn't cover the headlight. Or I suppose normally keep two motors on it - and on challenges, bolt on the third as you're probably not mothered about the headlight.

Drum wise, it can be a bit bigger diameter (the same as David's big drum version) but you gain more by increasing the width. The increase could be as much as 50% on width alone.

When I was making the first multi-motor Tds, the idea for this adaption occurred to me. Likewise, while I was making this - an even better idea sprang to mind. This time for a complete winch. I don't want to say too much at this stage - but it has several big improvements of what we are using at the moment. It is kind of a hybrid of an 8274, a Tds, a Husky, a Delta-Tek freespool and an automatic gearbox combining the best bit of each. Watch this space!


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