Stupid Question

[Cwalker935]

OK, I should know this but I do not. Should I be changing speeds, between, turning and sanding, or sanding and finishing? What speeds do you use throughout your pen-making process? I do not have varaible speed lathe and tend to turn, sand and finish at the highest speed. I have read other posts about finishing which call for reversing during certain finishing stages, I do not have a reverse and assume that I would get the same effect by flipping the tube from end to end on my mandrel or when TBC. I do change speeds for drilling. Sorry for what may be stupid questions, but I am self trained for the most part and have not seen these questions specifically addressed anywhere. I did find a thread from 2005 which seems to advocate faster is better with the exception of when applying CA.

 

[D.Oliver]

I'm no authority, but I sand and apply CA at a much slower speed than I turn at. I'm guessing 1300-1400 rpm for sanding and 500-600 for applying CA. But I would say do what works for you. If you're getting good results keep on doing what your doing at the speeds you're doing them at.

 

[stonepecker]

I sand at the lowest speed I can. I stop the lathe between grits and sand accross the blank/piece I am working on. I wipe all dust away or blow it away from the work between grits. Same thing with MM.

Applying finish such as CA .......S L O W ........keep it off the equipment and walls. Other finishes .... whatever I feel comfortable with.

Buffing, high speed.

 

[monophoto]

Absolutely - your finishing speed should be exactly 23.7r/min slower than your sanding speed.

Seriously - there is no single answer to that question.

Sanding is more efficient with the lathe running, but obviously, there are times when you must sand with the workpiece stationary. But when sanding with the lathe running, you need to work at slower speeds to avoid excess friction that leads to excess heat - you want to sand the wood, not burnish the surface. I tend to sand at speeds ranging from the bottom of the range on my lathe (about 275 r/min) up to about 750 r/min. But I don't think there is anything magical about specific speeds within that range.

Sometimes, it is better to apply finish with the piece stationary - that is especially true when using an oil finish that must soak into the wood. But there are times when running the lathe is recommended - for example, when applying a fairly thick finish (such as poly), running the lathe at a very slow speed helps level the surface and prevents the runs and drips. Likewise, slower speeds are useful when using a finish that is wiped on, and then wiped off. But very high speeds are called for when applying friction finishes that require heat to polymerize the finish.

 

[Edgar]

This is not advice - it is simply what I do and it works for me.

I have a 5-speed mini-lathe. It's not too difficult to move the belt to change speeds, but it does take time so I try to minimize speed changes as much as possible.

After lot's of experimenting, I've pretty much settled on doing almost everything in 4th gear (2200 rpm) - turning, sanding & finishing.

At that speed, you have to use a light touch for sanding to avoid burnishing as noted above. I use either Mirka goldflex or Mirka abranet - both are easy for me to control and avoid overheating at that speed. The added advantage is that when you have a good sanding technique at that speed, you can get it done really quickly.

I mostly use a friction polish but sometimes use Craft Coat. Friction polish is easy at that speed but Craft Coat took a little practice. I pretty much use the technique that Ed Brown demonstrates in his video at Exotic Blanks, but I've gotten to where I can apply it at 2200 RPM and get nice, consistent results.

I do slow the lathe down to 1st or 2nd gear when I apply a CA finish, but that's rare. I do all my blank drilling on my drill press, so that's not an issue for me.

Every once in a while, I do feel the need to slow the lathe down a little for certain blanks if they don't respond well when I start turning them at 2200.

FWIW
Edgar

 

[JimB]

I turn at high speed, sand at low speed and for a CA finish I start at slow speed and end at high speed. I have a variable speed lathe so it is easier.

 

[toddlajoie]

I'm with Ed, Moving belts is a PITA, so it I don't HAVE TO, I don't. Mine live in the middle/High range (not even sure what the RPM is) and the only time it moves is when it moves to the slowest belt for drilling.

IMO, if you have to slow down to keep the CA on the blank, you're putting too much on at a time. I did things that way for a while thinking it would build faster, and it did, but it also built up less even and required more sanding, which is counter-productive to building up faster.

As for sanding at higher speeds, again IMO (and YMMV...:biggrin with a light touch to reduce heat buildup and paper loading, you can sand the same amount in much less time.

 

[raar25]

I turn and sand 99% of my pens at the same speed 3500 rpm. Since the barrel is only 1/2" diameter by the time you sand the surface speed is only 4500 in/min. That is the same as sanding a bowl at 120 rpm. Use good paper that is not clogged or abranet and clean it often. I use a medium pressure and can tell when I am pushing too hard because the paper gets hot. I sand all man made materials wet also which takes care of heat.