speeding
- Thread starter T.allan
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PowerTool
Established Member
General rules are - smaller diameter,higher speed;larger pieces,slower speed (the issue is the speed of the surface of the timber as it goes past the chisel)
Also,out-of-balance/unusual shaped pieces need to be on slower speeds to reduce vibration.
And generally,you get a better finish from the tools if at a higher speed.
Andrew
Also,out-of-balance/unusual shaped pieces need to be on slower speeds to reduce vibration.
And generally,you get a better finish from the tools if at a higher speed.
Andrew
Bodrighy
Established Member
All that Andrew said plus...when finishing e.g. sanding, slower speeds are better ass a faster speed will often result in surface cracks as the wood is dried out by the friction. Wood is rarely totally dry and so sanding friction can dry the surface out.
Pete
Pete
CHJ
Established Member
Also on a balanced piece with differing densities or voids, the higher the speed the more even you are likely to cut the surface because of the shorter reaction time you have to influence the tool position.
Natural tendency with all of us when starting turning is to press the tool into the work to severely, if there is a hole or soft spot at slow speeds you tend to push the tool further into the wood when you hit them, this results in a chattered or corrugated surface. At higher speeds the tool has less time to advance into the soft spot.
Think car travelling on a corrugated road surface, at higher speeds the suspension does not have time to respond and the ride feels smoother as the tyres skip the tops without falling into the hollows.
Natural tendency with all of us when starting turning is to press the tool into the work to severely, if there is a hole or soft spot at slow speeds you tend to push the tool further into the wood when you hit them, this results in a chattered or corrugated surface. At higher speeds the tool has less time to advance into the soft spot.
Think car travelling on a corrugated road surface, at higher speeds the suspension does not have time to respond and the ride feels smoother as the tyres skip the tops without falling into the hollows.
Mornin' T.allan.
All the above, but if you are used to turning slow speed just increase it slowly. Then only as fast as you are comfortable with. As with all this turning lark, we all have our personal preferences.
Mine is as fast as the lathe will go, (as long as it stays on the floor) :lol:
All the above, but if you are used to turning slow speed just increase it slowly. Then only as fast as you are comfortable with. As with all this turning lark, we all have our personal preferences.
Mine is as fast as the lathe will go, (as long as it stays on the floor) :lol:
Mark Hancock
Established Member
All the above plus when deciding on what speed to use consideration has to be given to the lathe/bench/stand set up. On a heavier cast iron bolted down lathe you can turn at higher speeds than on a sheet metal wonder mounted on a cupboard standing on a wooden floor.
Also some tools do their job better at certain speeds eg for hollowing tools from 500 to 1000 rpm.
Also some tools do their job better at certain speeds eg for hollowing tools from 500 to 1000 rpm.
robo hippy
Established Member
Speed translates into feet per second, or meters per second. A small spindle at 3000 rpm is traveling at a slower mps speed than a 3 cm (I think that is about 12 inches, we Yanks don't really know how to think metric yet, at least not us older ones) bowl at 800 or so rpm. For cutting purposes, I prefer higher speeds as the wood cuts easier and cleaner than it does when I cut at slower speeds. I also am a production turner, so time saving is important to me, and I push my tools. I have a friend who comes over once in a while who turns on a Legacy Ormamental lathe which does all sorts of fancy spirals and such with router attachments, and has a high end speed of 200 rpm. That is the speed he uses on my lathe. It would drive me crazy to turn that slow, but that is what he is used to. When starting, I would recomend that you start slower, as you will probably find that more comfortable, and if you want to, GRADUALLY increase the speed. A frequency drive which offers true variable speed and torque at all speeds is really nice, and I can't imagine how I got along without it now that I have it. The stepped pulleys work, and are what I learned on, but can be difficult for bowls, because if you have a blank that is perfectly balanced and centered, that is more of an accident or luck than anything else. Starting a chainsawn blank at 500 rpm can be rather exciting on a light lathe.
For sanding, I prefer as slow as I can go. I turn green to final thickness, and let the bowls dry and warp before sanding. You can't keep a power sander on a warped bowl at more than about 20 rpm, and can barely keep hand sanding in contact with the wood at those speeds either. Fortunatly, my lathe could be adjusted to go that slow. Sanding at slower speeds seems to do a better job as well, you don't skip over the wood as much. I also keep my power sander at slower speeds. It has a max speed of 1200 rpm, and I put a piece of cork under the trigger to keep the speed at closer to 600 rpm. The surprising thing to me was that there was no difference in how much time I spent sanding.
robo hippy
For sanding, I prefer as slow as I can go. I turn green to final thickness, and let the bowls dry and warp before sanding. You can't keep a power sander on a warped bowl at more than about 20 rpm, and can barely keep hand sanding in contact with the wood at those speeds either. Fortunatly, my lathe could be adjusted to go that slow. Sanding at slower speeds seems to do a better job as well, you don't skip over the wood as much. I also keep my power sander at slower speeds. It has a max speed of 1200 rpm, and I put a piece of cork under the trigger to keep the speed at closer to 600 rpm. The surprising thing to me was that there was no difference in how much time I spent sanding.
robo hippy
