[reefy86]

having my plates sent of to be milled and drilled so i really dont want to make any mistakes here. so if i go of the bk12 ballscrew support here then the hole diameter according to the spec sheet is 6.6mm so then when adding tapped holes in cad (solidworks) and i select m8 tapped hole it gives me 6.8mm not 6.6mm is this correct or should i manually change the m8 from 6.8 to 6.6mm?

hope im making sense here

[peteeng]

Hi Reefy - what thread pitch? If its course metric then an M8 is 1.25mm pitch. This gives a nominal pilot hole of 8-1.25= 6.75mm Also is your file set at 0.01mm ? If set at 0.1mm it maybe rounding up the pilot dia. Another tap chart says 6.7mm another says 6.8mm. All work if into steel go the big size if in aluminium go the small size. Peter

https://parts-badger.com/drill-tap-referencing/

[reefy86]

Hi Reefy - what thread pitch? If its course metric then an M8 is 1.25mm pitch. This gives a nominal pilot hole of 8-1.25= 6.75mm Also is your file set at 0.01mm ? If set at 0.1mm it maybe rounding up the pilot dia. Another tap chart says 6.7mm another says 6.8mm. All work if into steel go the big size if in aluminium go the small size. Peter

https://parts-badger.com/drill-tap-referencing/

Hi sorry for being dumb here but how to I find out if its set to 0.01 or 0.1mm in the file? All I do in solidworks is go to hole wizard change type to tapped hole and size to m8 that's it. It's aluminium I'm using so if the BK12 support is asking for 6.6mm what would you guys set the tapped hole as if it was you? Again sorry for sounding dumb

[mactec54]

having my plates sent of to be milled and drilled so i really dont want to make any mistakes here. so if i go of the bk12 ballscrew support here then the hole diameter according to the spec sheet is 6.6mm so then when adding tapped holes in cad (solidworks) and i select m8 tapped hole it gives me 6.8mm not 6.6mm is this correct or should i manually change the m8 from 6.8 to 6.6mm?

hope im making sense here

Would have to see the Support drawing, they normally have clearance holes for SHCS 6.6mm would mean that is for a 6mm SHCS so your taped hole size would be a max of 5 mm for 6mm Capscrew

[mactec54]

Hi sorry for being dumb here but how to I find out if its set to 0.01 or 0.1mm in the file? All I do in solidworks is go to hole wizard change type to tapped hole and size to m8 that's it. It's aluminium I'm using so if the BK12 support is asking for 6.6mm what would you guys set the tapped hole as if it was you? Again sorry for sounding dumb

Do you have the Support Housing you would be best to use 1/4-20 UNC cap-screws ( Should fit and still have some clearance ) this would need a .200 Holes Tap size holes, for this cap-screw, as 6mm cap screws are not as good in Aluminum