[JMay]

As the title states a simple tyre grinder that is mostly 3dp with the addition of some parts obtainable from the local hardware store and the slot spares box.

   

The motor pod and axle assy pivots on a 5mm rod and the height above the sanding disc or paper is controlled by the knob (with a nut insert) which has a bolt from the base up through it and held under compression by a spring. The rod has a clip ring so the pivot can be withdrawn and the pod removed for servicing etc.

Needs a low rpm boxer motor (NC5 here) with good torque 9:30 gearing and single flange bearings. 



   

   

   

It is not a Hudy but it will grind a pair of tyres equally at a pace determined by the power supply and motor heating. 

STL files below.

Cheers JMay.

EDIT: From feedback I revised the Pod to take complete inline axle assemblies that use double flange bearings avoiding the need to remove wheels from knurled axles.  Revised STL file below. 

   

Revised Pod with bearing retainer STL file

Base plus axle retainer.stl Size: 1.81 MB  Downloads: 12

[Kevan]

Another great option on a budget 

[MrFlippant]

Is this meant to be a simple scuffing machine, or is it meant to TRUE the tires?

[Kevan]

It looks like it would both Greg.

[JMay]

Mr Flippant,

It is a machine that depending on the nut, can.. 

1. Rip the tyres to shreds
   
2. Spray chunks across the room
   
3.  Melt tyres
   

or if built with care and consideration and operated by someone who knows what they are doing will 'TRUE' tyres i.e. the end product will be 2 tyres of equal diameter concentric to the axle with a smooth finish. 

Try reading the text, it is not a Hudy but a simple machine that any one can make if they have a printer and some spare parts.

If you don't like the design then respectfully I suggest you supply your own STLs to the forum.

[MrFlippant]

Respectfully, I read the text, and examined all the photos closely before I posted for clarification on the purpose of the device. My only concern is that the sanding surface appears to be stuck down with what might be double sided foam tape, or looped over tape. At the very least, it does not appear to be firm or flat. For tires to be true, that surface would need to be firm and flat. I hope you take this feedback in the way it was intended, which is not to knock your device, but to help you improve it.

[woodcote]

Thanks again John for posting more files that SlotRacer members can access free of charge 

This tyre grinder looks another great project for slot car enthusiasts who have a printer - or might be getting one for Christmas. Perfect for some festive fun - and nicely trued tyres for 2022.

[JMay]

Mr Flippant,

Difficult to reconcile post 3 with the ‘explanation’ in post 6, I always welcome constructive criticism and post 3 was not constructive in any way shape or form, and frankly came across as arrogant hence my reply.

To address your concerns the surface of the base is going to as flat as the printer setup, if less than perfect then it is a simple task to add an aluminium plate and compensate if required in the height of the pivot. In use the sanding medium is pushed against the base creating a flat surface to the degree of the previous point. I have used round sanding discs which are rigid and various grades of sanding paper without issue, the key is the application which is the responsibility of the user. Bottom line it is a simple unit that can be printed and then developed further.

I keenly await the free issue of your designs to the 3dp forum.

JMay

[JasonB]

Looks good to me.

[Kevan]

Greg has a Tire Razor reciprocator add on freely downloadable on thingiverse.