Took a few sanding abrasives for a test run

[Neil Strong]

Note: this thread is a re-posting of material posted in another woodturning forum.

I have been giving a few different abrasives a 'test run'. Nothing too technical, just integrating them into my normal work flow and noting some times and observations.

This was just a suck-it-and-see on a few abrasives that came to my attention. Any omissions are coincidental and don't imply anything in particular. I'm just sharing what I discovered in my workshop doing what I predominantly do, making bowls and power sanding them to a level acceptable to the galleries where I sell my work, ie to about #400, plus a bit extra if required depending on the piece and the wood. The few exhibition pieces that I make from time to time get extra attention but that is not the level of finish I'm referring to here. I'm just sharing what I found in case it's of any value to anyone else, without any pretense of expertise or objectivity.

With the exception of a brief period of using Noretake's Astra Dot, Norton's Champaign and some Kingspor, I have been using various no-name velcro backed abrasives purchased in rolls from variuos suppliers from which I have cut my own disks. Economical but perhaps not as efficient as some of the newer abrasives or maybe even value for money. So, I thought it was about time to try out and compare a few other options.


For me, efficiency is more important than durability (but not at any cost... :rolleyes: ). By efficient I mean how quickly and predictably I can get to desired level of finish. Cleaning out clogged abrasive, stopping to swap spent abrasive papers, having to go back to eliminte out-of-range renegade grits, having to spend extra time repairing the surface after an overly aggressive prior grit, all come into the efficiency equation and not just how rapidly the abrasive cuts the wood.


A reminder that there are two flexible abrasives grit size standards (ANSI/CAMI in USA & FEPA, the 'P' ones, in Europe). For example #180 in both systems is about 80 microns, whereas the USA #400 is 23 microns but the Euro P400 is only 32 microns. And, should you go from USA #400 to P600 (26 microns) you will be going back to a coarser grit, not a finer one. This needs to be kept in mind if making comparisons or abrasives are being mixed from different manufacturers.

There is a lot of other technical stuff to know about abrasives, none of which I've attempted to cover here.


The abrasives I tried:

My current batch of No-name Alox 2" - all grit sizes
Vince's Blue Flex* 2-3/8" - #100, 150, 220, 320, 400
Vince's Ceramic* 2-3/8" - #120, 180, 220
3M Scuff Brite pads* - aprox #320, #800, and #1200
Vince's Cera~Max* 2-1/2" - #120, 180, 280, 400
Norton's Dry Ice 2" - #120, 180, 240, 320, & 400
Noretake's Astra - single dot - #120
Kingspor - various

* These abrasives also required an interface pad like this (http://www.vinceswoodnwonders.com/Firm%20and%20Soft%20Inneraface%20Pads%20.htm) to fit the standard 2" mandrel.


Next post on: How quickly did they finish the job?

[Neil Strong]

How quickly did they finish the job?

Starting with the next available grit above #80, each grit was worked through until I got the best finish I could at #400. Very subjective, I know, but from experience I expect that my standard would satisfy most turners. Each piece was inspected under 40x magnification and with a bright LED light after the last two grits to check for any residual scratches not readily visible to the naked eye.

A new set of disks was used for each surface, except for the Dry Ice where I only had one set of each grit. These were gratis so I could include them in the test run.

The lathe ran at about 1500rpm and the disks at 3000rpm for the lower grits and the lathe progressively slower for the higher grits (down to 250rpm). A very light touch was used.

A separate duration test was conducted and reported in a later post.


Abrasive: Vince's Ceramic Grip to #220

Wood: Oak, Diameter: 9" bowl, Surface: outside, Time: 35 mins + #320 buff for 8 mins, total 43 mins
Wood: Oak, Diameter: 9" bowl, Surface: inside, Time: 30 mins + Vince's Blue to #400to for 20 mins, total 50 mins
Silky Oak, Diameter: 7.5" bowl, Surface: outside, Time: 25 mins + Vince's Blue to #400 for 7 mins, total 32 mins


This ceramic was very aggressive, removing a lot of wood very rapidly but leaving a rougher surface than the grit rating would indicate which then required an effort to remove with the follow up abrasives above #220, and as a result the overall time to completion wasn't that good.

The sample Ceramic Grip kit included #320, #800, and #1200 Scuff Brite pads to complete a piece after the Ceramic #220. I didn't find these pads very abrasive or sufficient to complete a piece on their own. Closer intervals between the grit sizes may have worked better. These pads may have also allowed for renegade lower grits to be re-introduce and to re-scratch the finish, but I didn't have time to confirm this with further testing.

I also found that the white #1200 will burn if allowed to dwell on stationary wood... :-(

The Ceramic Grip and Blue Flex 2-3/8" disks and the Cera~Max 2-1/2" disks all provide more abrasive than standard 2" disks (roughly 50% more) which is nice to have, especially on the outside of bowls, but I found them to be too large for the inside of small and medium bowls. They also require an interface pad to run on the standard 2" mandrels. There are some claimed advantages to using these adaptors, including saving the hook surface of the more expensive mandrel and selecting different densities of backing for different applications, but these may not be advantages that are seen as important to every turner.


Abrasive: No-Name Alox

Wood: Blackwood, Diameter: 7" bowl, Surface: outside, Time: 40 mins
Wood: Blackwood, Diameter: 7" bowl, Surface: inside, Time: 43 mins

The coating on the grit quickly wore off the No-Name abrasive but there was no clogging evident. The rate of wood removal began to slow towards the end of each grit. Going by the nominated grit size, the grit intervals were not predictable. With some effort the end result was satisfactory but slow.


Abrasive: Astra Dot + Kingspor

Wood: Mango, Diameter: 10.5" deep bowl, Surface: Outside, Time: 30 mins


I only had 3" disks for these abrasives so only used these on the outside of the test bowl.

The surface left by the #120 Astra Dot (the finest I had above #80) was the roughest of any left by the #120 abrasives. I then proceeded on to the #120 Kingspor which was needed to clean up the rough surface left by #120 Astra Dot. I was, however, reminded how grippy the Kingspor is. Too grippy for me to consider as an option with my fast and light technique. The time to get to an acceptable finish was better than the two previous tests, but not so pleasant getting there IMO.

Running up through the Astra Double after the Single Dots and then onto the finer Champaign often used after those may have been a different experience, but I didn't have those to hand so can't comment on that option.


Abrasive: Dry Ice

Wood: Blackwood, Diameter: 12" platter, Surface: outside, Time: 35 mins
Wood: Blackwood, Diameter: 12" platter, Surface: inside, Time: 30 mins

Quick and aggressive, but loaded up chronically. However, surprisingly it had the best #400 that I tested, doing a good job of removing the #320 grit abrasions and also leaving minimal visible marks itself. The time taken to clean out the clogged abrasive was included in the overall times, which left it under performing despite its rapid rate of the abrasive cut.

The Dry Ice comes as a standard 2" disk, so didn't need any adaptors and would also work quite well inside smaller diameter bowls.


Abrasive: Vince's Blue Flex

Wood: Mango, Diameter: 10.5" deep bowl, Surface: inside, Time: 30mins
Wood: Blackwood, Diameter: 9" bowl, Surface: inside, Time: 35mins
Wood: Oak, Diameter: 8.5" bowl, Surface: outside, Time: 24 mins

The Blue Flex had a firm bite with minimal or no clogging. They did not feel as if they were nearing exhaustion towards the end of each grit and I expect they would kick on for a bit more than just one surface of a bowl of this size. The duration test will give a reading on this. It required my best efforts to get a satisfactory finish at #400 to avoid some fine residual abrasions, the sort that are just discernable with the naked eye under strong angular light. In defence of Blue Flex, they also supply a #280 between the #220 and #320 which I chose to skip when I was buying. The addition of this extra grit may have given a better outcome at #400.


Abrasive: Vince's Cera~Max

Wood: Cherry pine, Diameter: 8.5" bowl, Surface: outside, Time: 23 mins
Wood: Cherry pine, Diameter: 10"diam deep bowl, Surface: outside, Time: 20 mins
Wood: Cherry pine, Diameter: 10" diam dee bowl, Surface: inside, Time: 20 mins

This abrasive is a blend of ceramic and traditional alox. The claimed benefit is the best of "ceramic for long lasting wear and aluminum oxide for even grit consistency".

The Cera~Max worked quickly and smoothly, with minimal or no loading, but again I found that I had to concentrate to eliminate all residual abrasions at #400. There is a #360 disk that wasn't included with the sample pack and expect that this could make a noticeable difference to the quality of the final finish, albeit at some cost to the time required to finish the job. Given the speed of this abrasive, the addition of another grit to more readily get a better finish would add just a little extra time (3 to 4 minutes) and still leave it as the fastest abrasive I tested.

Cera~Max disks are 2.5" diam. My sample pack didn't come with the 2.5" interface pad so they overhung the supplied 2-3/8" adaptors. Had I been able to use the matching 2.5" interface pad I may have got even better results on the speed and endurance tests.

Next post on: Durability

[Neil Strong]

The purpose of this test was to see how long each abrasive make would effectively work or how long before the backing failed. What might still be 'effective' for one person may have long gone past that point for someone else. For this test (but not necessarily how I work) the criteria was to use the abrasive until I could no longer feel a positive bite or until the stream of sanding dust coming off the wood dropped to about 1/3 of the initial volume. The two things usually happened about the same time. The volume of dust coming off the wood was observed at the mouth of the dust extractor hose intake which was positioned next to the work piece. A light coloured wood (Cypress) was selected so the dust from this could be clearly seen against the dark interior of the extractor intake. The outside of the same shallow 20" bowl was used to test all abrasives.

The #80 abrasives were initially selected for this endurance test, but after nearly 45mins on the first disk and about 10mm off the outside of the 20" bowl I gave that idea away. It was becoming an endurance test on me too. So I selected #180 instead, a better idea as this is about the mid-point in the normal sanding range and where the majority of the ground work is done for a good finish. And, all of the #180 abrasives should be predictably rated at about 80 microns, irrespective of the rating system.

Here are the times for the #180s.

Dry Ice #180: 18 mins
Ceramic #180: 18 mins
Kingspor #180: 10 mins
Blue Flex #180: 9 mins
Cera~Max #180: 9 mins
No-Name #180: 8 mins

As I did not have any Astra Dot #180 I ran a separate test with a fresh Astra #120 and compared this to Vince's #120 Ceramic and Cera~Max. All three abrasives were cut to 2"diam so I could run it on my standard 2" mandrel to avoid the interface pad cooking problem experienced during the #180 endurance test run, reported below.

Here are the times for the #120s.

Cera~Max #120: 70 mins
Astra Dot #120: 38 mins
Ceramic #120: 31 mins

In the case of the Cera~Max I gave up before it did. It was willing to keep going, I wasn't! It had made its point and I was ready to go home... :-)

A longer run time was expected at the lower grit, but what was not expected was the significant switch in performance between the #180 and #120 Cera~Max and Ceramic. For want of an explanation, the composition of Cera~Max is predominantly ceramic in the lower grits but progressively switches over to alox in the higher grits. So at #180 the Cera~Max was behaving more like an alox abrasive than a ceramic.

Not obvious from the raw times was the difference in how much wood each of these #120s was removing. The Ceramic and Cera~Max began by removing at least twice as much wood as the Astra. Not surprising given the difference in the amount of grit on each. At about the 13min mark the Ceramic was down to removing about the same as the Astra did initially. And, the Cera~Max kept removing wood at a rate exceeding that of the Astra for the full duration of the test. So the Astra removes wood more slowly but persists for longer than the Ceramic, by a bit, but it didn't start to compete with the Cera~Max on rate of removal or duration.

There had been no observed difference in the rate of wood removal during any of the #180 endurance tests.

Another observation was that the Astra Single Dot threw the dust the least distance from the disk of any of the abrasives. This in part came from the dust not clinging to the wood and being slung away. The dot pattern would be the reason for this. As a result the dust extractor inlet was able to capture most of the dust before it escaped. This feature may be important to some.

Two other things to report. In the aborted #80 test run the backing on the Dry Ice disk failed at the 40 min mark. It was the only disk backing to fail during any of the tests. I also had two of the required interface pads cook during the duration test. The velcro layer started to separate from and move on the foam interface layer resulting in buckling and risk of total failure. Admittedly the #180 endurance runs were a harsh test exceeding normal practice, but worth noting anyway for anyone who might push these limits. @$4 a pop it's a consideration.


184688 184689


I had intended to repeat the durability test run on a decent piece of hardwood, but at this point my enthusiasm flagged. The results could be different if I had. Perhaps another time.


Next post for: Emma Chisset and some personal conclusions

[Neil Strong]

Emma Chisset and some personal conclusions

The other part of the equation, Emma Chisset:

Vinces's Blue Flex, if purchased in packs of 100 - @12c
Vince's Ceramic - if purchased in packs of 50 - @48c
Vince's Cera~Max - sold in packs of 50 - @17c
Norton's Dry Ice - if purchased in packs of 50 - @41c
Noretake's Astra Dots - sold in packs of 10 - @84c
Noretake's Astra Dot - disks cut from roll - @10c
Norton's Champaign - disks cut from roll - @10c
No-name Alox - disks cut from assorted rolls - @<5c

Note - these are all ex-supplier prices, no shipping costs included. There could also be other suppliers that I didn't happen upon who may offer a better price point and change the price/performance sweet spot for you.

The required interface pads for the three abrasives from Vince is another cost consideration that needs to be taken into account along with the fact that you are getting about half as much abrasive again as a standard 2" disk.


Some personal conclusions

On speed alone, the Cera~Max is very attractive, while its durability excels at the lower grits it sits acceptably along side the other lower priced options at #180. I also quite liked the feel of the Cera~Max on the wood and the finish. The durability of the required interface pads is still a question, as is the size. Those 2.5" disks will need to be cut down to go inside smaller and medium sized bowls. The economics of doing that is another consideration.

The pure ceramic options (Vince's Ceramic and Norton's Dry Ice) sure rip off the wood quickly but leave a surface that requires extra time to tame with non-ceramic abrasives. My results indicated that the overall time to completion wasn't significantly improved by using them. Their extra cost was commensurate with their durability but there is a question over the durability of the Blue Ice backing. Its propensity to clog was also a negative for me.

If speed is not such a factor for someone then Astra Dot is worthy of consideration, especially if you cut the disks yourself from rolls. Using a full set of Atra Single and Double Dot disks may also give a different result. It's non-clogging performance in wet and oily woods is a feature that may be an additional attraction for some turners.

I'm giving Kingspor a miss myself because of its grippy-ness but others may not mind or may even like this.

The abrasive I'm still not decided on is the Blue Flex. I think I need to get the missing #280 that I left out of my order to see if that makes any difference on the overall time to get to a good level of finish. I'm also going to have to give the interface pads more of a trial under normal working conditions.

So, for me, the price/performance sweet spot is looking like Cera-Max, and possibly Blue Flex, with a few questions still to be answered.

Whatever I decide, I don't think I will be staying with my current No-Name abrasives. Yes, cheap but not very efficient.

Your mileage may be different, but hope this has been of some use to you.

And, finally, some words from an acknowledged sanding expert, Bill Neddow,

"just remember, the sandpaper business is very competitive. You get what you pay for. Those extra cents you pay for the more expensive papers translate into longer lasting grit, better glues, backings and velcro and a more consistent grit pattern - which cuts down the potential for those frustrating scratches that suddenly appear at times.

I know of only one shortcut that actually saves money – cutting your own disks." See his article, "Sandpaper: New Grits, New Techniques, and Results of 10 Years of Testing", in Woodturners America *here (http://www.woodturnersamerica.com/index.php?option=com_content&view=article&id=99:sandpaper-new-grits-new-techniques-and-results-of-10-years-of-testing&catid=65:editorials)*

[John Keeton]

Great review, Neil!!! Glad you got to try the Cera-Max - I haven't had an opportunity yet to use them. I suspect your production greatly exceeds mine, and with the more artsy stuff I do, I mostly hand sand with sheet goods.

While I have not used nearly all the brands you have used, the Blue Flex has served me very well, and my very limited use would mirror your comments on them. The cost difference with the Cera-Max is not significant in dollars, but it is nearly 50% when viewed as a percentage - pretty significant. I would want to see at least that much more in time saved. For me, that is the real test factor. I cannot replace my time, and at my age, every extra minute is valuable. Wish I had back all the minutes/hours/days I wasted in earlier years!!

Again - thanks for the review! Very well done and very broad in scope.

[bob svoboda]

Great review and very helpful, Neil. Thank you for taking the time and making the effort to share this study.

[Bernie Weishapl]

Thanks for sharing a great review. Very helpful.

[Reed Gray]

I am curious as to the high speeds you use. Vince is the one who convinced me to sand with slow drill speeds, and slow lathe speeds, though with my warped bowls, speeds above 30 rpm are impossible to use. I have found the slower speeds to be more effective, and perhaps even a bit faster. I wonder how slowing down the speeds would effect the results. I didn't notice much difference between Vince's ceramic and blue flex discs and the Norton Dry Ice discs for durability and cutting ability. Astra Dot wasn't even close. I had no problems with the Norton Dry Ice clogging up. I do use the LDD soak which makes a noticeable difference in ease of sanding, and probably contributes to the discs not loading up. I have no problem sanding out a 3 bowl cored set (14, 12, 10 inch bowls) with one set of discs. While the discs can 'feel' dull, they still cut well. I do use the 3 inch discs. As Mike Mahoney said, a 3 inch disc has twice the surface area as a 2 inch disc does.

robo hippy

[Neil Strong]

I am curious as to the high speeds you use. Vince is the one who convinced me to sand with slow drill speeds, and slow lathe speeds, though with my warped bowls, speeds above 30 rpm are impossible to use. I have found the slower speeds to be more effective, and perhaps even a bit faster. I wonder how slowing down the speeds would effect the results. I didn't notice much difference between Vince's ceramic and blue flex discs and the Norton Dry Ice discs for durability and cutting ability. Astra Dot wasn't even close. I had no problems with the Norton Dry Ice clogging up. I do use the LDD soak which makes a noticeable difference in ease of sanding, and probably contributes to the discs not loading up. I have no problem sanding out a 3 bowl cored set (14, 12, 10 inch bowls) with one set of discs. While the discs can 'feel' dull, they still cut well. I do use the 3 inch discs. As Mike Mahoney said, a 3 inch disc has twice the surface area as a 2 inch disc does.



Robo Hippy, I've noted your well informed comment before about slower being better. Most highly experienced woodturners that I know, particularly those that do spindle work, advocate this as well. I have worked with both fast and slow speeds and so far I have found that fast works better for me, particularly in the coarser grits. However, I'm always open to change my ways, if there is a better way. Must admit that I had settled on the faster speed based on the quality of the finish and not the time taken to get there, so might add the slowmo method for a few of the front runner abrasives to see if I can detect any difference. If both you and Vince advocate the slow/slow technique it's certainly worth taking another closer look at it.

Interesting observation about the LDD preventing loading.

John - I'm with you on needing to save wasted time/energy as I watch my hourglass indicate that I'm getting closer to the end of my run. And, spending any more minutes than I need to standing there mindlessly sanding is one thing I would really like to eliminate...:D

[David E Keller]

Thanks for taking the time to post this, Neil. I'm glad you like the ceramax discs because I just ordered a boat load of them. I've been using Vince's blue discs, and I've been pretty happy with them. After talking with him, I decided to give the ceramax discs a try.

[Harry Robinette]

Neal
Very nice job allot of good stuff.You should check out Bill Neddow's site, He's done a 11 or 12 year study of sanding high and slow speed also documented almost every sand paper there is.He's done Demo's on the abrasive system's at Cincinnati Symposium the last couple of them.You and him should get together and collaborate that should get sanding time down to 30 sec.or so.
Thanks for all the info.that had to be allot of work.
Harry

[Neil Strong]

Neal
Very nice job allot of good stuff.You should check out Bill Neddow's site, He's done a 11 or 12 year study of sanding high and slow speed also documented almost every sand paper there is.He's done Demo's on the abrasive system's at Cincinnati Symposium the last couple of them.You and him should get together and collaborate that should get sanding time down to 30 sec.or so.
Thanks for all the info.that had to be allot of work.
Harry

Thanks Harry for the pointer to Bill Neddow's article on High Speed Sanding (http://www.johnjordanwoodturning.com/John_Jordan_Woodturning/Bill_Neddow_-_High_Speed_Sanding_23.html). A very interesting read. Certainly a case of Bill forgetting more than I ever knew!

I did laughed when I read that Bill uses and recommends Tim Skillton's sanding pads... as I have for years. But, then, Tim just lives down the road from me so that might be expected, besides it being a very good bit of gear. So good that I have one for every grit, in 1", 2" and 3"... :o

[Vince Welch]

Hi Neil,

Nice comparison and thank you for taking the time and effort. A couple of things come to mind that I want to touch on.
1. The Scuff Brite non woven pads are not designed too remove material but to burnish at high speeds rather than remove material and I think you came to realize that. It is one of the only products I offer that advocate speed. The maroon leaves more of a matte finish, grey burnishing more in the 800 mesh range (a bit more sheen) and the gold burnishes at 1200 where you will see sheen. Perhaps I need to point this out on the site better.
2. You are correct concerning the lower grit of the Cera~Max Discs holding more ceramic then lessening to completely A/O in the higher grits.
3. Concerning speed... I was also in Cinn years ago when Bill presented and have read his article and postings concerning speed and with all due respect I am in complete disagreement with Bill concerning this topic. I have worked with people in solid surface shops IE bathroom vanities, cabinets, etc etc for years and what I have found is slower is better. The guys in the shops understand this and practice this in addition also using a soft innerface at higher with a light touch. Here is the reason! You basically have two things going on when sanding... One cutting/scratching... whatever you wish to call it... Second you have skidding/skating... whatever you want to call it. The whole idea is you want to maximize your cutting and minimize your skating over your surface. The way this is accomplished is by lowering your speed especially as you get into the higher grits! That is to say obviously 400 grit is far less aggressive then 80 grit. Because 400 is less aggressive then 80 grit if you try to sand (400) at the same rate of speed(80) there will obviously be much more skating and skidding taking place. Skating and skidding increases heat/melts Velcro, and wears the discs dramatically. Yes... there is dust flying at the high speeds and it might even look like you are getting a lot done but the percentage of actual sanding vs. skidding is what is being addressed! Efficiently is where it is at! Yes you are creating more dust at higher speed b/c of the surface contact but at what point is your percentage of skidding more then your percentage of cutting/scratching? What I talk to people about is maximizing one's efficiency and minimizing ones frustration (burning up discs and Velcro while obtaining poor sanding results). Simply put high speed and too much pressure create friction... friction creates heat...heat fractures abrasives prematurely and melts Velcro... etc etc. Initially, it might seem that a sanding at a slower speed is a longer process but if you are able to raise your sanding success rate to 9 out of 10 times and maximize your disc life your sanding frustration has decreased and your sanding understanding/education has increased! We talk about tool finesse knowing your turning tools when they need to be sharpened etc... I invite you to practice your sanding finesse just the same way as your tool finesse. Keep the drill close to your body... try not to allow to get sanding catches (yes there is such a thing...) come to know when the disc you are using are not cutting like it should and replace it the disc. Use air to blow dust from your project in between grits. In talking with the thousands of folks over the years I believe many people are focused more on tool finesse not having stop to consider sanding finesse and the benefits. How can you tell when the discs are cutting or not cutting when you have all your speeds (lathe and drill) wide open?!?! You can't! Well... unless you wait till you finished sanding only to find sanding marks that you were hoping would go away by the time you hit your sanded with your last grit and they didn't! At that point if you are like me your frustration is high and your success is low.
Well I guess I more then touch on the topic but that is why we have SMC and we all check in. Feel free to call me 1-877-284-8969 if you have any question that I can answer.
Vince
P.S. Oh Bill says use light pressure.... that I agree with!!! LOL! V

[Neil Strong]

Thanks Vince for the detailed input on speed.

I'll give the slowmo another go and see what happens.

Just to get a benchmark of what you would call slow, what lathe and abrasive speeds are we talking about at say #80, #220 and #400 on, for example, a 12" bowl?

[Reed Gray]

I have several of the Sioux/Milwaukee angle drills. I run them with a piece of cork under the trigger, so max rpm is in the 600 range. I seldom max it out to that level. My warped bowls are impossible to keep any abrasive on at speeds above 25 rpm. I had Brent English help me reprogram my phase converter so it will go that slow. My old PM3520A would go that slow as well. The B model shuts off at 50 rpm. I did call PM and asked them about that, and they told me that the motor would overheat and fry the electronics. I told them I had sanded out thousands of bowls at those low speeds, and it ran cooler than when I was turning. They told me that was not possible. Go figure.... If I do have a problem spot, I will turn the drill speed down lower in the 100 or so rpm. It really does seem to cut better. One side benefit is the bearings in my drills last longer. At the slow speeds, I get 400 to 450 bowls (from 3 to 16 inches), and at the high speeds, it was 300 to 350.

From Steve Antonucci," Use sandpaper like my 4 year old uses toilet paper."

robo hippy

[Neil Strong]

I have several of the Sioux/Milwaukee angle drills. I run them with a piece of cork under the trigger, so max rpm is in the 600 range. I seldom max it out to that level. My warped bowls are impossible to keep any abrasive on at speeds above 25 rpm. I had Brent English help me reprogram my phase converter so it will go that slow. My old PM3520A would go that slow as well. The B model shuts off at 50 rpm. I did call PM and asked them about that, and they told me that the motor would overheat and fry the electronics. I told them I had sanded out thousands of bowls at those low speeds, and it ran cooler than when I was turning. They told me that was not possible. Go figure.... If I do have a problem spot, I will turn the drill speed down lower in the 100 or so rpm. It really does seem to cut better. One side benefit is the bearings in my drills last longer. At the slow speeds, I get 400 to 450 bowls (from 3 to 16 inches), and at the high speeds, it was 300 to 350.

Thanks for that, Robo Hippy.


From Steve Antonucci," Use sandpaper like my 4 year old uses toilet paper."



.... :D

[Vince Welch]

Hi Neil,
That is a good question! When I sand a 10-12 inch bowl (thanks for not using metric on me) I always start with 80 maybe 100 grit! Generally, the speed is around 600 RPM. Truly, that is probably a bit fast to start sanding with and for that I am guilty. However, I have plenty of discs laying around and am able to swap discs as needed but also I progress through grits taking small steps such as 80, 100, 120, 150, 180, etc etc and as I progress I slow my lathe speed down each grit change. So, by the time I am sanding at 120 grit I am around 400 RPM or so... to be honest I am not really sure exactly what speed I am sanding because I focus my attention on the pull or resistance of the disc against the material I am working. Keep in mind this will all vary slightly depending on the wood species you are working with. What I do know is I always seem to land on 50 RPM when I get to 220 or 280 grit. 50RPM is the slowest my lathe will spin without me making computer changes which I do not wish to perform. Here is the thing... 320 grit is a very fine grit!!! Many turners do not think of 320 as such because often we can sand to 600, 800, 2000 etc. But flat wood workers usually sand only to 220 grit at most and often only 180 grit. My point is this... having the lathe spinning while sanding at high grits such as 320, 400 grit is not necessary because we know sanding at 320 and 400 grit we are no longer removing deep scratches or even scratches that are visible to the naked eye... they should be gone! We removed those scratches with the lower grits 80-150 grit. 180-280 grit took care to medium scratch marks. At 320 grit and beyond I often turn off the lathe and rotate the piece by hand. At this point all I am doing is fogging or clouding the piece as I call it and compressed air is very beneficial at this point to remove the dust from the wood pours.
While I am here let me also talk about Pneumatic Random Orbital Sanding. Pneumatic sanding can be valuable at the higher grits but not designed to be used on lower grits such as 80-180ish. People talk about getting a smoother sanding finishes using pneumatic sanding and that is great but here is something important to understand. Random Orbital Sanders (ROS) generally have about a 2.5mm orbit. That 2.5mm orbit works great when you get to your fine sanding because the sander provides a finesse sanding action that removes fine and very fine scratches but to remove deep scratch marks a rotary action works much better and is the right application for the job. Also, note that ROS require a lot of CFM and a minimum 60 gallon compressor is recommended. You can use a 30 gallon but anytime your compressor is running more than 15-20 minutes per hour you risk derogating the motor life of your compressor especially of the unit is a oil free compressor as so many are at that capacity. This information was told to me directly from Cambell Hausman representative who manufacture most of the compressor tanks here in the states.
So with all that said, I want to say thank you Neil! I applaud your time, energy, and efforts regarding providing good information. Thank you again! Moreover, to back up what I have stated in this thread I want to offer anyone who wishes to take advantage of the information on this thread to do so by getting free samples of discs to try when you place your next disc order. What I ask is that you read this thread again and curtail your sanding. Slow things down a bit and use the fresh discs I provide! All of them from start to finish and you are the judge! I am confident that you will be pleased with your new results! This may cost me a lot of money but more importantly it is about education and helping one another. Vince
P.S. Neil are you aware that your water swirls the wrong way when going down the drain in Australia? LOL JK! Vince

[Neil Strong]

Thanks Vince for the detailed response.

My current lathe goes down to 30rpm which should be a fair test.

Just one last question, what speed do you run your sander at?

Got that water swirl thing completely wrong! The last time I was in the US I thought yours was swirling the wrong way down the drain, which helped to explain a few other mysteries about the Stateside way of life...:confused:, but if your right, I'm back to being even more mystified...:D