04-08-2012, 11:16 AM
Wong,
Flat and level, a surface plate is normally very flat, it can however be slightly higher (not level) on one side due to how it was mounted.
This doesn't mean the surface plate is not usable, it is still very flat just not quite level. So one places a marble on it and it runs off - still flat.
If your lathe slopes a bit towards the headstock, or tail stock, or even towards or away from you it does not matter. Like you have mentioned the bed must have no twist in it.
If the lathe is just bolted down to something without shimming under the lathe "feet" it is very easy to introduce a twist in the bed. So one does have to be a little careful. This is were a machinist level does come in very handy.
That said, bolting your lathe down will help with dampening the vibrations especially at the higher speeds.
DaveH
Flat and level, a surface plate is normally very flat, it can however be slightly higher (not level) on one side due to how it was mounted.
This doesn't mean the surface plate is not usable, it is still very flat just not quite level. So one places a marble on it and it runs off - still flat.
If your lathe slopes a bit towards the headstock, or tail stock, or even towards or away from you it does not matter. Like you have mentioned the bed must have no twist in it.
If the lathe is just bolted down to something without shimming under the lathe "feet" it is very easy to introduce a twist in the bed. So one does have to be a little careful. This is were a machinist level does come in very handy.
That said, bolting your lathe down will help with dampening the vibrations especially at the higher speeds.
DaveH