VISUAL Drill Speed differences

[leehljp]

I posted the below on cmcfalls" "Drill Press Speed", but feel that this picture deserves its own post. Chigdon's encouraging response made me think about doing this.


Below is a pict of drill speed results done by an on-line engineer friend of mine on another forum. It is clear to see that the overall speed increase makes for smoother cuts. That test was done in soft pine which will exaggerate the problem of roughness. It does not reflect what will happen in most of the woods that are used in pens. It does reflect the what using the wrong speed for a given wood or PR. PLEASE NOTE the chart below the picture as it gives the correct speed for different density woods in relation to the bit size.

The above paragraph was edited for Dario and Redfish who could not understand my Japanese form of English.

The original link is from BT3Central and was posted by LChien; The pict above is posted with permission from him. To see the original link Click here!.

Please don't think that 3000 RPM is the best for all wood and all sizes as there are variances - see this:
Recommended Drill Speed Chart for Different Wood and Bit Size:
http://www.woodmagazine.com/wood/story.jhtml?storyid=/templatedata/wood/story/data/85.xml

(The size above was increased so that no one else would miss it.)

 

[redbulldog]

Hank:
Thanks for the information, and another chart for my collection.

 

[Dario]

No disrespect to you or your engineer friend Lee, but soft pine is a poor material for the test.

Though the pic looks very convincing...it actually is misleading IMHO.

EDIT: The linked chart does make more sense and note that most woods we use may even be harder than hard maple...so slower settings than shown may work even better.

 

[redfishsc]

Dario is right about most of our pen woods being harder than hard maple. Hard maple is on par with ash and red/white oak, yet woods like bubinga and cocobolo and ebony are light-years harder.

By the way, interesting test. I may have to try to duplicate this on some hard maple I have laying around the shop.

 

[leehljp]

Originally posted by Dario
<br />No disrespect to you or your engineer friend Lee, but soft pine is a poor material for the test.

Though the pic looks very convincing...it actually is misleading IMHO.

EDIT: The linked chart does make more sense and note that most woods we use may even be harder than hard maple...so slower settings than shown may work even better.

I am Puzzled: RedFish, Dario, did I not make it clear that the picture was from a woodworking forum and demonstrates the need for right speed for the right wood and right bit size?

I don't think that I implied that "this is the speed and wood" that pen turners should all use, or did I?

I fail to see a problem. Please bare in mind that wood working and pen turning all deal with huge amounts of variables and therefore common sense helps in recognizing the differences in principles versus absolutes. I never stated that faster is always better or that pen turners should guage this as their wood of choice. The principle that can be derived from the visual picture is to realize the wisdom of choosing the correct speed in relation to the diameter of bit and wood of choice. Hope this helps.

AS for the picture and chart, it is right on -
Chart: 1/4 to 3/8 in drill in soft pine is listed as 3000. Exactly what the picture shows.

So, the right speed produces the best results and it does for soft white pine too! I do not understand your concern that soft pine is a poor material for a test. It is wood and soft pine is noted in the chart. WWs often use cheap and handy materials for tests and the cheaper material results prove to offer good analogies and tests too. I knew very well the first time I saw that picture 2 years ago that I should not use those speeds on rock hard maple, but the picture in pine made me more aware of the different speeds.

The picture does tell that that wrong speed can lead tear out and in many cases for pens - blow outs. Some of the blowouts in my opinion are due to the smaller <b>mass</b> as Eagle made note in one of his posts. I think that blowout will result at times even with the right speed for the bit and wood - because it is the nature of certain oddball wood grains that we use.

One speed is not optimal for all situations. One speed with one bit size is not optimal for all woods either. But the Picture does grab our attention and make us think. The<b> wrong</b> way to use that picture is to think "faster is always better" or that soft pine is the definitive wood.

 

[ctEaglesc]

The picture shows interestiong results.
One thing I noticed right off the bat.
The holes were drilled cross grain.
Most of is drill end grain.
Just a note and not a comment on the test.

 

[chigdon]

Maybe I am missing something here but it was my understanding that the engineer who did this test was using soft pine cross grain so you could see the differences in the effect on the grain with the naked eye as opposed to snakewood that would probably need a microscope to tell the difference.

I agree with one primary rule here -- if what you are doing is working, don't change. All I know is when I bumped up my drill speed I stopped having blow-outs.

 

[Dario]

Originally posted by leehljp
<br /> <b> It is clear to see that the overall speed increase makes for smoother cuts. That test was done in soft pine which will exaggerate the problem of roughness. But it is clear to see that slower speed (or dull bits) will have more a tendency to "tear" the wood, catch and cause blow outs. </b>

Lee,

The test may be right on for the material (which penturners hardly use)...but as I said the pic is misleading especially coupled with your comment.

There will be lots of people who will see the pic, read your comment and that is it. Face it, not everyone stay online as long as others do (me for example) and consider the other factors.

If the test was done with cocobolo...do you think it will persuade others to slow down? At first glance with this, they will speed up. What's bad is (as I said)...it looks very convincing. Thus the misleading comment.

 

[ctEaglesc]

What kind of bit was used?

 

[leehljp]

Originally posted by Dario
<br />

Originally posted by leehljp
<br /> <b> It is clear to see that the overall speed increase makes for smoother cuts. That test was done in soft pine which will exaggerate the problem of roughness. But it is clear to see that slower speed (or dull bits) will have more a tendency to "tear" the wood, catch and cause blow outs. </b>

Lee,

The test may be right on for the material (which penturners hardly use)...but as I said the pic is misleading especially coupled with your comment.
There will be lots of people who will see the pic, read your comment and that is it. Face it, not everyone stay online as long as others do (me for example) and consider the other factors.
If the test was done with cocobolo...do you think it will persuade others to slow down? At first glance with this, they will speed up. What's bad is (as I said)...it looks very convincing. Thus the misleading comment.

I guess the real problem here is that some people do not have any common sense or can't read the whole thing. CONTEXT Context! It is in the Context and Written to boot!

QUOTE: <b>Please don't think that 3000 RPM is the best for all wood and all sizes as there are variances - see this:
Recommended Drill Speed Chart for Different Wood and Bit Size:
http://www.woodmagazine.com/wood/story.jhtml?storyid=/templatedata/wood/story/data/85.xml</b>

 

[leehljp]

Hey guys,

Use some common sense here. This was a simple test that was done over two years ago. For your benefit, perhaps I should go back in time and tell the guy that his picts would be viewed on a pen forum in the future and therefore he should do his test on a nice burl. If there is a problem with it being done cross grain, or in pine, I do not think it would be a waste for you guys to do a test on a $50.00 piece of wood to show us what correct examples are. I would appreciate seeing it and I am sure everyone else would love to see it too.

Dario,
you have plenty of wood, so it would be very gracious of you to do a 5 speed test like this in cocobolo, one test in an amboyna burl with the grain going every which way, one in hard maple. It would be nice to see it a 5 speed test done in zebra wood end grain, angled and cross grain too.


Eagle,

While I do not know what the engineer used specifically, I do know that he keeps his bits sharp (Drill Doctor) and IIRC - he generally uses or sharpens to 118°. He usually buys his bits from MLCS, but I do not think that the ones used here were brad point. I would like to emphasize that he and most on that forum go in for very strict tolerances - i.e. not prone to house framing tolerances but more like a hundredth of an inch (in wood for those who cannot understand context. I know that a hundreth of an inch is not that good in the metal world but wood moves more than that with humidity changes, So a hundreth of an inch in wood is very good.)

 

[ctEaglesc]

So a hundreth of an inch in wood is very good.)

LOL
remember your talking to a <b>GUY</b> whose bits are all buggered up and "eyeballs the tube to the butt end of the bit to determine if its'"Close enough" for Government work to select which but to use.
"This aint rocket science" and I don't need to drill a hole THAT exact to glue in a friggin tube.[]
Edit for usual reason... I can't type

 

[Marc Phillips]

LOL
remember your talking to a gut (drink less beer [] ) whose bits are all buggered up and "eyeballs the tube to the butt end of the bit to determine if it's "Close enough" for Government work to select which but to use.

*whew* ... I am glad to know I am not the only one who does that []

 

[leehljp]

Its good to see a sense of humor here. [] Some guys get so hung up on wording that it almost ain't worth helping. BTW Eagle, I wasn't making that "hundredths of an inch" comment about you, just at those who get persnikity about the exact wording. And it ain't easy for a redneck who does half his thinking in a Japanese context. [)]

 

[Dario]

Originally posted by leehljp
<br /><b> Its good to see a sense of humor here. [] Some guys get so hung up on wording that it almost ain't worth helping.</b> BTW Eagle, I wasn't making that "hundredths of an inch" comment about you, just at those who get persnikity about the exact wording. And it ain't easy for a redneck who does half his thinking in a Japanese context. [)]

I agree on this one 100%. [] Seems some people are so hung up, they got one track minded and can't see/hear what the other person is trying to convey. [)]

FYI, My english is probably worse than yours. I am also Asian...from your poor neighbor (Philippines)...so I did understand your post perfectly even before the edit []

Great info on the linked chart though...hope more people use it. Thanks for sharing![^]

 

[ctEaglesc]

Originally posted by Marc Phillips
<br />

LOL
remember your talking to a gut (drink less beer [] ) whose bits are all buggered up and "eyeballs the tube to the butt end of the bit to determine if it's "Close enough" for Government work to select which but to use.

*whew* ... I am glad to know I am not the only one who does that []

I don't think that is possible, I have sober over 13 years(but I am not supposed to count.)

"Close enough" for Government work to select which but to use.

That should be "bit" as in drill bit.[^]