Vertex Double Pulley CNC made in Aluminium T2,5/19-8


Are you in?

  • Yes
  • No

0 voters

since I have the Vertex the Belts/Pulley issue is the most unlikely thing in my opinion. I just couldn’t get along with the grinding belts. So now I have decided to orden a couple CNC made and therefore I have created a technical sheet and a new pulley.

  1. It would be very helpful if someone could verify my technical sheet.
  2. It would be very helpful if someone could print the pulley and give me a feedback on it’s design, because my printer is waiting for spare parts.
  3. Are there any backers for this Project? Yesterday I did the first Request for Proposal, the company says 50€ for a single piece and about 15€/pcs if I order 100 pieces.

So how many do we get together? If there will be enough people I will take the risk and put the 99 I don’t need on Ebay, so everyone can buy them as they please.

There is the CAD files and Pulley 20 T2,5/19-8 Technical Sheet.pdf … 9ggaa?dl=0

Also I will upload it to but I have to wait 24h with a new account.

I will continue asking CNC company’s till I get the best price and quality, keep you guy’s in the loop.


PS: The German word for pulley is “Riemenscheibe”


So your idea is to just make the toothed length 3.5mm more wide…
Not sure it’s THE solution. The belts won’t be wedged and “Forced” rubbing against each-other, that’s for sure.


The construction will always cause some movement of the belt running either upward or downward.
You can’t exactly position the motor pulley perfectly aligned with the rod, that’s the biggest factor and will possibly cause it to make contact anyway.
Also going from 15.5mm (orginal flange to flange) to 24mm (flange to flange) in length will cause the shim side pointing to the bearing to rub against the bearing holders.
(I had grinded a few mm’s from the bearing holders to prevent this, mine flange to flange is a total of 20mm)
So It’s pretty essential to resize the total thickness where you thread in the grub screw yours is 6mm thick. Grub screw is 4mm long so take ~2mm or something.
(the original thickness that’s threaded is only 1.75mm)

IMHO it’s better to add a shim in between so the belts can’t make contact AT ALL!
So while you’re busy producing some fancy custom pulley I would go a step further than only increasing the length with 3.5mm…
That’s my opinion, after experimenting with them myself for a annoyingly long time.

My Setup for over 10 months!

I did this with 2 single belt pulleys, which I trimmed off and have the grub-screw hole positioned in-between 2 tooth.
Works great so far…
The biggest issue I have experienced are that the grub screws are hardly ideal this way, they need to be flattened/shortened a bit so they are completely countersunk with the bottom of the tooth, that makes them really tricky to handle and not ruin them entirely!
But it runs amazingly and unexpectedly smooth like you have never seen before!

Kind Regards!



thanks for you input. I also thougt about the middle shim like this modell but I had a discussion with a friend who is mechanical engineer about that and he told me that it would be much more work and with that more cost for a CNC to produce the pulley with a middle shim. So that’s why I chose this disign. But I will include that question withhin my search for a producer. Also I though it should be easy to print a shim and glue it in the middle.

The thread thickness for the screw should be no problem if it is pointed to the right side. But you are right with the bearing holder, the pulley with belt has a diameter of 16mm, so I change the size of the “left” shim to 17mm since 1mm should prevent the belt from slipping of. Would that be enough? How many mm have you grinded off?

Template T2,5/16-5 Type OF



And I don’t want produce a “fancy” item, it just should be a good thing for all of us who have the same problem. And thank’s again for sharing your solution :slight_smile:


I can’t give an exact number I have grinded off, I did something like in the pic below.

One more issue: If you want to have the grub screw on the right-side like in your picture, you will restrict the printhead movement.

My conclusion was the following: At first glance it looks like you got enough space on both sides, but actually putting it on reveals a whole new can of worms to handle…

Sorry for my bad choice of word :stuck_out_tongue: fancy I meant in a good way :wink: No guerilla style like mine :stuck_out_tongue:

Kind Regards


Yeah the movement… I forgot/ignored that because I didn’t used the whole space ones. I will check that.



Hey again,

the bearing holder needs to be modified in order to gain 5 mm with possibility that it is necessary to grind the self-locking nut till it’s flat as the holder.

I messured:

Rod to Wall = 8,5mm
Rod to Holder = 3,5mm --> Necessary for the thread thickness and for the screw —Orientation will be to the left :wink:
Holder thickness = 5mm

Is there anything else to think about? I will change the plans tomorow.


Yeah somehow the Spambot inactivated my “Luzz” account… Whats the words blacklist? When it will be activated again? Two days?

Here are the drawings with and without a shim in the middle.

The CAD files found in the Dropbox link from the first post.


Dang, see that’s what I meant with “Fancy” pulley!
Pretty much looks perfect, only drawback off-course will always be the bearing holders.
But if you’s start making the ones with a shim, I’m buying a few Immediately.

Good Job!

Kind Regards!


Looks really good :slight_smile:

i would also directly buy a couple of those with a shim.

Keep up the good work :slight_smile:

best regards



Yeah thanks

please lets not hype the pulleys with a shim to much, I just draw that to complete the task of “doing it right”. In the last two days I was spending most of my day finding and contacting companys.

Guess what they said? Two possible answers:

  1. We can’t do that at all
  2. We can do that without the shim

Still some answers open…

So I guess we should think more about “pimping” the pulley by printing a shim and glue it in the middle. Would be a little more work but still worth the affort. Run it without the shim also would still be better than with the normal pulley.

I will keep you in the loop.

PS: I could do that my job, kinda like it :slight_smile:



that should be the new bearing holder.


Hey, today I got the first offer for the middle shim version, it says 15€ for one by production of 100pcs.

So then it would be 30€ + Shipping for two pcs.

Still waiting for a couple more offers.

A Company in China would produce the “without middle shim” version for 3€/pcs. That’s definetly the best price but it’s not secury what I really would get for the money.





the last price offer has gotten to me. Mostly I asked company’s in German for production of the 100pcs. The price range has been from 25€ to 10€ for one pulley with middle shim. Also I asked companys in China, the best price was 7,5USD/pcs.

That would be then 20€ for 2pcs + Shipping. Good price when you compare to the original for 30€/2pcs + Shipping from England.

But for 4 people that have voted til today I will not gone order the pulley’s. It’s just too risky. If there will be more people that join in here I will consider it again.