Quorn Belt Guard

[John PurdyParticipant @johnpurdy78347]

Now that I have a 3D printer I decided I should print a belt guard for my Quorn Mk1. I have only been using it for 10 years without. To be honest it was the article in the last issue of MEW by Alan Bryan on “3D printing in the Home Workshop” that got me thinking about it.
Next I guess I should look at a wheel guard. Not sure how crash resistant it would be out of PLA (PETG?). Perhaps make it with 4 or 5 wall loops, 50% or more infill, and a total thickness of 4-5 mm it would be strong enough to resist a burst wheel?

The small hole at the left end was for an 1/8″ pin with a 60 Deg. point to register in the end of the motor pulley to aid in positioning the guard centred on both pulleys to spot through for the mounting bolts.

John

[Grindstone CowboyParticipant @grindstonecowboy]

I don’t think I’d completely trust any of the usual 3D printing materials as a wheel guard if a stone were to explode. Unless you go for one of the fibre reinforced one, then PETG might be your best bet as it won’t shatter to quite the same extent as PLA or ABS.

Rob

[BazParticipant @baz89810]

If you want a guard make it out of metal, as thick as you can manage, I have seen a couple of grinding wheels shatter and it is not pretty.

[noel shelleyParticipant @noelshelley55608]

ONLY use steel for a wheel guard 1.6mm +, printed plastic will not contain an exploding wheel spinning at 3000rpm or more. Noel.

[John HinkleyParticipant @johnhinkley26699]

John (Purdy)

How disappointed you must feel to have received those negative comments.  I know how much time and effort goes into making something like that.

I had initially posted a response with a proposal to line the guard, but having looked at your photo again, I realise that it’s NOT a wheel guard at all – it’s covering the drive belt as you state in the thread heading.  I misread that, too.  I would have thought that PETG might be better choice or even carbon or glass fibre reinforced filament.

Neat looking design, by the way.  The finish appears clean as well.

John H

 

[John Hinkley]

On John Hinkley Said:

John (Purdy)

How disappointed you must feel to have received those negative comments.  I know how much time and effort goes into making something like that. I hate to admit it, though, but I’m sure they’re right.  Metal is the way to go.

On a more constructive note, is there sufficient space within your design to add a sheet steel liner to your plastic guard to at least afford some degree of anti-shatter?

Lacking the skill and fabrication facilities to produce a sheet metal cover and without the experience or training to know any better, I would probably have followed the same route as you did, maybe utilising either PETG or glass or carbon fibre reinforced filament.

John H

 

Better to feel disappointed than to spend half a day in casualty having bits of grinding wheel picked out of what’s left of your face. OK you can’t bend a bit of metal into a circular shape and you don’t have any mates who can weld, get yourself down to the local iron mongers and look for a nice thick stainless steel saucepan, her indoors tells me you can get 4 or 5 inch diameter ones, and cut it down to suit, it may not be ideal and I make no claims that it will work and cannot recommend that you do it as I don’t want your lawyers banging on my door if it goes pear shaped, all I do know for certain is that I would rather have something steel surrounding my grinding wheel than a bit of 3D printed plastic.

[John HinkleyParticipant @johnhinkley26699]

Baz,

Your response is to my original comments.  My later reply, which was a (heavily) edited version of the first, as quoted in your reply.
In my edited reply, I pointed out that it is not a wheel guard but a belt cover as stated in the thread title, which I failed to read properly. It seems I wasn’t the only one!

John H

Further edit:  Oh dear! I’m really getting my knickers in a twist!  I re-read John Purdy’s post and now realise that it was displaying his belt guard and went on to postulate the viability of a similar arrangement for the wheel guard.  THAT was to what the subsequent responses were referencing, a fact that I hadn’t appreciated.  If I offended anyone, I apologise.

John H

 

[Graham MeekParticipant @grahammeek88282]

Hello John,

That is a very nice belt guard. Is the machine light a home brewed thing or is it commercially available?

Regards

Gray,

[egaParticipant @ega]

If the safety issue can be resolved, then a 3D printed *wheel* guard could presumably incorporate a vacuum extract connection.

I felt distracted by the noise of my shop vac when used with my own Quorn and resorted to drilling a hole in the workshop wall so that the vac could function in the next room.

[baz]

On baz Said:

Better to feel disappointed than to spend half a day in casualty having bits of grinding wheel picked out of what’s left of your face. OK you can’t bend a bit of metal into a circular shape and you don’t have any mates who can weld, get yourself down to the local iron mongers and look for a nice thick stainless steel saucepan, her indoors tells me you can get 4 or 5 inch diameter ones, and cut it down to suit, it may not be ideal and I make no claims that it will work and cannot recommend that you do it as I don’t want your lawyers banging on my door if it goes pear shaped, all I do know for certain is that I would rather have something steel surrounding my grinding wheel than a bit of 3D printed plastic.

With the same disclaimer as Baz … May I suggest that a thick deep-drawn Aluminium saucepan might be an even-better starting point.

The  material is obviously ductile and should therefore absorb energy.

MichaelG.

[John HaineParticipant @johnhaine32865]

John, please could you share the print files?

[John PurdyParticipant @johnpurdy78347]

Gray

The machine light is a re-purposed old reading light of my grandfather’s (circa mid 1950s) with the goose neck removed and re-mounted on the top of the switch box. It uses a 12V #93 car parking light bulb, the transformer and a two position switch are in the original brown box seen on the back of the switch box. I had been using it sitting on the bench but it was never in the right place or always getting in the way.

John

I though about publishing the files but I am not sure how much use they would be, as others Quorns would have to have the same centre distance between the motor shaft and the spindle for it to fit. Also the mounting holes would have to be in the same location. If you want the files just PM me your e-mail address and I will send you both the FreeCAD and .stl (or .step) files.

As far as my comments on the WHEEL GUARD goes I was just thinking out loud and they seem to have enlisted some very definite opinions! My initial thought was to make a cast aluminum one, which I think, is probably the way I will go.

John

[John PurdyParticipant @johnpurdy78347]

Please excuse my grammar. In my comments above on the wheel guard “enlisted” should have been “elicited”. It didn’t sound right when I wrote it but couldn’t think of the right word, duh. Spelling was never my high suit!

John

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