What is the required mm??

I keep buying the wrong size bearing for the 608zzf, does anyone know the exact mm size for the 48x30 longmill? I cannot seem to reach customer service for my life…

Will this link help? I’m really not sure how to use it but when I click where the bearings go and then measurements it says, diameter 15.875 mm

LongMill Benchtop CNC MK2 | Custom V-wheels (onshape.com)

Sorry if this was no help to you. At least you know someone read your question.

Here is the link for the Flange Bearings

LongMill Benchtop CNC MK2 | 608ZZ Deep Groove Flange Bearing (onshape.com)

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EDIT: This information is for the 30x30 bearing only.

Using the measuring tool on @Swinly’s link for the flange bearing I got the following measurements.

Non Flange part:

  • 22mm in diameter
  • 5.5mm in thickness

The flange:

  • 25mm in diameter
  • 1.5mm in thickness


  • 8.02mm in diameter

EDIT: Reading my own post I realized that the bore is for 8mm lead screw and I think that bearing is only for the 30x30. I will try to find the one for the 48x30 and report back.

@Danmedancnc According to the bill of materials you want two 6001zz flange bearings for the 48x30’s T12 lead screw. I could not find that bearing on OnShape but the bearing number should help you to get the correct bearing.

Does it have to be flanged or will it work just fine without it?

My problem is their are 7,8 and 10 mm holes for the 608zzf and I cannot get an answer from anyone which one it is

What axis is the bearing for? I have been thinking it was the X axis but I just reread your OP and it doesn’t mention which axis it is for. The X lead screw is 12mm and the Y and Z are 8mm lead screws.

If it’s for the X axis you don’t want a 608zzf you want a 6001zz as shown in the bill of materials.

The following is an excerpt from the bill of materials, the 608zz is for the 8mm lead screw. The second is 6001zz for the 48x30 X axis with a 12mm lead screw.

608ZZ Flange Bearing deep groove, C5 clearance
6001ZZ Flange Bearing deep groove, for T12 lead screw, qty of 48x30 x2

I found these for the X axis on Amazon. They don’t say ZZ but I looked that up and ZZ just means metal seal on both sides and these bearings appear to have metal seals on both sides.

And for the Z and Y axis I found these 608zzf bearings with the 8mm bore.

And yes it needs to be flanged to keep the lead screw in place.

I hope this helps. If I may ask, what happened to the bearings that came with your MK2? If they were missing or the wrong size I would try to contact Sienci. I know you said you couldn’t get a hold of support but not sure if you called or used that form so I put a link in case you need it.