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[Nick W]

My Laser DIY Alignment Tool is now in the prototype stage:








And the parts:



And the bad news is: it doesn't work! Yet.


The problems are: the cheap 5mw laser module isn't powerful enough to use in daylight; the power leads are just taped across a CR2032 battery; and the mounting post isn't long enough.


Those are fixable, by buying a better laser(I'm tempted to go straight to a 100mw version) and a switched battery holder, then making another post. The post you see in the pics was already an offcut which I faced and threaded to suit; a longer one won't take long now I've sorted my technical issues.  Once I know how long the post needs to be, there's no need for it to screw into the base. It would just be pressed and epoxied into place which requires fewer operations.


So far the prototype owes me £4 for the laser module, and I only paid that much because I wanted it quickly. A better one will be about £25 which isn't too bad. The aluminium I had in stock for just this sort of job. Development will continue.

[05omegav6]

Promising start

[Nick W]

It's a terrible photo, but here's the general idea:





You can barely see the red cross, so a more powerful laser is definitely needed; my plan is to graduate a horizontal line for the toe, and a radius for the camber. That's once I've figured out where to position the flag, and worked out the distances.

[Diamond Black Geezer]

Keep up the good work.

Once finished, just needs laser-etching 'Nick W Tools Ltd England' on it and you've got a marketable product!

Well impressed so far

[Nick W]

I've machined a longer post, which will put the laser 120mm away from the wheel - twice as far as the original.





The post is larger as well as longer, so I might have to reduce its size a bit. The laser is bigger too, at 16mm diameter. I went with a 250mw one as the listing suggests it has a 15metre focusable range and was only £2 more than a 100mw version.


While the lathe was setup for 1.5mm pitch threads I made myself a decent sized wheel fitting stud, as the ones I had are both plastic and very short:





That's 1/2" rod, threaded M12x1.5 and the end rounded off, so it ought to be plenty strong enough for the heavy 17" wheels. I must remember to put it in the car before I lose it

[05omegav6]

There might even be a slot for it in the spare wheel foam 

Laser guided geometry system looks to be developing nicely

[terry paget]

That wheel fitting stud looks very useful, especially for wheel changing on wet nights.
I am not clear exactly how you will set camber and toe-in using your laser tool. What is your plan? 

[Nick W]

That wheel fitting stud looks very useful, especially for wheel changing on wet nights.
I am not clear exactly how you will set camber and toe-in using your laser tool. What is your plan?

The flag will have a vertical/horizontal cross marked on it, the centre of which will be at the wheel centre-height and the same distance away from the car's centre line as the laser. The 'vertical' part of the laser cross will read off a graduated arc to measure the camber, and where it crosses the marked horizontal line will display the toe. This will require careful placing off the flag, and some trigonometry to work out the graduations.
The intention is to be able to measure the camber and toe for all 4 wheels with an absolute minimum of setting up. That will involve ensuring that the flag is in the same place each time, and I expect to use a permanent feature(like a mounting bolt, slot etc)under the car to do that.


This sort of job was traditionally done with a string-box around the car, and a lot of extremely fussy setting up, measuring and calculating at each alteration. The commercial 4-wheel alignment rigs use the same principles but the setting up is simplified, and the measuring/calculations hidden from the operator.  All of which allow it to be profitably used on many different vehicles.My apparatus is vehicle specific; the custom fixtures should mean the calculations only have to be done once, and the results read directly.

[Nick W]

There might even be a slot for it in the spare wheel foam 

Laser guided geometry system looks to be developing nicely

That's long gone; I'm using the space for a first aid kit, socket set, screwdrivers, tyre-inflator and foam, hiviz vest etc.

[05omegav6]

Stuck to the jack with velcro

[terry paget]

That wheel fitting stud looks very useful, especially for wheel changing on wet nights.
I am not clear exactly how you will set camber and toe-in using your laser tool. What is your plan?

The flag will have a vertical/horizontal cross marked on it, the centre of which will be at the wheel centre-height and the same distance away from the car's centre line as the laser. The 'vertical' part of the laser cross will read off a graduated arc to measure the camber, and where it crosses the marked horizontal line will display the toe. This will require careful placing off the flag, and some trigonometry to work out the graduations.
The intention is to be able to measure the camber and toe for all 4 wheels with an absolute minimum of setting up. That will involve ensuring that the flag is in the same place each time, and I expect to use a permanent feature(like a mounting bolt, slot etc)under the car to do that.


This sort of job was traditionally done with a string-box around the car, and a lot of extremely fussy setting up, measuring and calculating at each alteration. The commercial 4-wheel alignment rigs use the same principles but the setting up is simplified, and the measuring/calculations hidden from the operator.  All of which allow it to be profitably used on many different vehicles.My apparatus is vehicle specific; the custom fixtures should mean the calculations only have to be done once, and the results read directly.

Many thanks. The only lasers I have ever seen project a spot with a narrow coherent (parallel) beam. Your laser appears to provide a vertical line; clever. The only wheel alignment I have watched has been at tyre shops, with the car sitting on a ramp with slits or mirrors attached to the front wheels and at a height enabling track rod adjustment. The ramp was presumed  horizontal, though all measurements were relative to the other wheel on the same axle. Your method appears to make measurements and settings relative to the vehicle's horizontal and vertical axes; commendable and challenging. I await developments and wish you luck.

[Nick W]

The better laser arrived, so I now have this:





A comparison:





The new one is 16x68mm and 250mw compared to 12x30 and 5mw. In daylight it projects a nice clear cross along the hallway, unlike the original which had about 1metre range. It came with a 5volt 1amp mains power supply, so my plan is to use a USB powerbank. I've ordered a cylindrical one with an on/off switch, and intend fitting it into another hole in the post. This will keep the whole thing entirely self-contained.


Next step is to do the maths for the readout,  which I've been putting off for some reason.

[Diamond Black Geezer]

Keep it up. Looking very good thus far. 

[Nick W]

The powerbank arrived - it seems I had changed my mind, and ordered a more powerful rectangular one that I can use for other things - so I soldered a USB connector on to the laser wires, and have this:



The cross is much clearer than it looks in the photo.


And I drew a quick cross on the flag to give an idea of my thinking:







Things to do:


1)  align the laser cross with the mounting post - I need to find a better spirit level than the £2 plastic thing I use for shelves. We've got one somewhere.


2) The laser needs to be parallel with the ground - the mounting post is square so a spririt level will set that.


3) The readout flag needs to be more robust than the current floppy plastic, g-clamp and offcut of steel channel manage.


4) The markings need to be drawn accurately, and some way of ensuring that the upright line is vertical. A plumb bob should do.