Letter to RPM conversion chart

[JPG]

"W" s/b 5100

[reible]

"W" s/b 5100

It was a test. You passed.

I fear a lot of things are not understood or glossed over. I noticed the glitch in the curve and sure enough I messed up but I was too lazy to fix it so I thought I'd just leave it in there and see if any one would 1) notice, 2)correct me, 3)have no idea what I was showing and not ask about it.....

We use to have to make up these multi million dollar proposals for funding of prospective projects. Several of us would work on them, usually with a very short time frame so we started having fun with it. We did that by hiding our initials in graphics and adding things like "shop towels" as line items. You know 2 million for circuit packs, 1.5 million for personal, 800K for new labs, and of course $25 for shop towels. We were always pretty successful so either no one of the big shots noticed or loved our humor. Never had anyone ask us to removed these easter eggs.

Ed

[JPG]

Actually there is an abrupt slope change between W and fast.

A gander at the porkchop reveals the reason(motion gets 'over the center/90° point).

Also the control sheave is bottoming out(belt is bottoming out).

[ERLover]

rieble/Ed, have you not noticed, nothings gets past JPG, imagine being one of his kids growing up and trying to BS the "old man".

[JPG]

rieble/Ed, have you not noticed, nothings gets past JPG, imagine being one of his kids growing up and trying to BS the "old man".

Yes they were more successful BSing the "old lady".

But not by much!

[jsburger]

rieble/Ed, have you not noticed, nothings gets past JPG, imagine being one of his kids growing up and trying to BS the "old man".

Yes they were more successful BSing the "old lady".

But not by much!

[ERLover]

Most moms know, they are just a bit more forgiving to there children.

[Ed in Tampa]

I have a question. Perhaps it is dumb but I am curious.
Who cares about what the RPM is? My dial has setting for doing every process and that is where I set the dial. Why should I care about the RPM?

When I turn I decide if 750 is slow enough, if it is I then use the speed that results in the best cut in that piece of wood. Each piece is different and knowing RPM would not help.

If I am drilling I look on the dial where it says drilling and set the speed in that range. If the feed rate isn't good I adjust speed up,or down until it is cutting right. Again depending on the material, drill sharpness, my heavy handedness on the feed and lub all effect the speed. Knowing that setting that may change with each piece being drilled means nothing.

I agree you must know the highest and lowest speed to make sure the machine can handle the project but who cares if you are sawing at 3420 versus 3460?

[charlese]

Good point, ED! Maybe I should have said, Good Question!!

Back when I had the dial up, headstock, I never could give a hoot about RPM. Still don't, really! but the PowerPro headstocks display RPM rather than letters. Therefore the mention of RPM.

There are buttons to push that give "standard speeds" for individual operations. The ones I use mostly are 3450 which is for sawing and 1300 and something for sanding. (I said 1300 something, because can't remember the exact number without looking) I just look at that button the same way I would look at the letter area on my old headstock.

There is an up and down pair of buttons that allow changes in rotation to make an operation feel; right.

[reible]

Time for a fictitious story since we all know this doesn't happen in real life, or does it?

So I just came home with a box of new drill bits. They are not twists bits and they are not brad point but rather some bullet pilot-point bits. I'm planning on drilling some hard maple with them. The hole I need is 3/8" and I have a bunch of holes to drill.

I've been using standard twist bits and know that the 3/8" bit should run at some where near "G". I also know that if this were a brad point bit it would be better run at "A". But these bits are not either of those.

So what letter do I use to drill these 79 holes? Well I could go with the "A" or I could go with the "G". So one of the big selling points on these new bits is how fast they can drill. So that "G" is sounding good. I drill the first hole and find that it is nether wonderful or fast.... Dang wasted my money on these.

But wait, perhaps I'm drilling at the wrong speed. I'll have a go at "A". Worse! Now how can that be?

Wait I saved the package maybe it has a speed chart??? Sure does, now what letter do they want me to drill at? What no information on shopsmith speed letters just these dumb rpm settings. Great! or should that be not so great?

According to the chart hard maple with the 3/8" bit needs 3000 rpm. Is that near "A"? I have no idea. Is it near "G"? Again no idea cause I don't have a way of finding the relationship of letters to rpm.

Oh yea just the other day someone ask for such a chart and I saved it to my computer. Let's see 3000 rpm is "P"! Boy am I glad I saved that chart now. OK I set the machine at "P" and drill, wow what a difference!

Well after reading what I wrote I sure can see why I don't need that chart anymore so highlight and delete that worthless file.............

OK now the wife just got home with this mirror thing she wants me to mount in the bathroom. What it needs a couple of 1/8" holes drilled in it??? The guy at the home center sold her a special drill bit that drills glass??? What not a shopsmith speed letter to be found, that's OK I used "P" last time and this bit is so much smaller it'll work.

Twenty minutes later I have to confess to the wife that her new mirror was defective. Yes it broke when I tried to drill it. Well it could have been that cheap glass bit I guess at least I know its not my fault. "You paid $75 for that!" Moral of the story is that its never your fault but sometimes you pay, twice. And next time you drill at 750 rpm not 3000 rpm, at is an "A" not a "P".

Still don't give a hoot? Well that is what fictitious stores are for.

Ed

I have a question. Perhaps it is dumb but I am curious.
Who cares about what the RPM is? My dial has setting for doing every process and that is where I set the dial. Why should I care about the RPM?

When I turn I decide if 750 is slow enough, if it is I then use the speed that results in the best cut in that piece of wood. Each piece is different and knowing RPM would not help.

If I am drilling I look on the dial where it says drilling and set the speed in that range. If the feed rate isn't good I adjust speed up,or down until it is cutting right. Again depending on the material, drill sharpness, my heavy handedness on the feed and lub all effect the speed. Knowing that setting that may change with each piece being drilled means nothing.

I agree you must know the highest and lowest speed to make sure the machine can handle the project but who cares if you are sawing at 3420 versus 3460?