I have the 770MX with the BT40 spindle. I am trying to set the tool “0” reference height using the Tool Height Setter Dial Indicator (or any other flat surface), so that I can set my tool heights following the Tormach manual instructions. What surface on the BT40 spindle do I touch to the indicator to touch off to (ie set z height) so that I can touch off the other tools to find tool length?
This is a pretty good video on this topic. You don’t need the ball you can just move the tool setter under the spindle nose to set the height. Tormach’s also got good youtube videos on this topic.
You can touch off the spindle on the drive dogs or the space between them. I believe Tormach recommends touching off on the dogs but it really doesn’t matter. I always touch off between the dogs, mostly because I didn’t see the Tormach recommendation before I started doing it that way. Been working perfectly fine for me going on 2 or 3 years now.
Thank you, both videos helped. I understand now that the main cylindrical base of the spindle is the reference, not the flanges/drive-dogs. I think I understand that touching off to either of the main spindle surface or the drive dogs and then the tools will be correct because it is all relative.
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Ya I touch off on the main part of the spindle, not the drive dogs, but it probably doesn’t matter.
Scott
Hello @Tanya_Garcia-Nolen
The official answer is that you can use either the dogs or the spindle. However, there are a few things to keep in mind when deciding what you want to use:
-Whichever you are using for tools, you have to use for all your tools, and you also have to use for work offsets. If you are picking up all your work offsets with a tool, then this point is a little irrelevant, but if you want to use the machine to pick these up then this is something to keep in mind. Not all parts allow the clearance to engage the whole spindle to their face.
-The dogs can get scuffed or worn over time and are not always the exact same height as each other. If for whatever reason you need to reset the height of the indicator, this will create discrepancies in your tool offsets.
I’ve seen people that don’t like using either because they are worried about damaging the spindle during touch-off, so they hold a 1-2-3 block against the spindle, which also works. Whatever you use matters less than making sure you are always using the same thing.
I hope this info helps you out.
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