HSD Spindle RPM Range

[ironsides]

Hello to HSD spindle owners,

My PRSalpha 48 X 48 with a HSD spindle has been ordered and will be here 2nd week of Sep.

I would like to know what the Max/Min rpm's are available for the HSD Spindle. I couldn't find it on the SB web site?

Thanks n advance.

George

[david_white]

0-18k rpm

[ironsides]

Thanks David,

Is there a lose/gain of torque at the high and low end of the rpm speed range?

George

[thewoodcrafter]

Man, I would think they have a power curve graph on there website.

But most spindles develope max HP between 10,000 and 18,000 RPM. Below 10,000 the power starts dropping off.
Every manufacturer and model has differences of course.

[knight_toolworks]

you can't run the spindle too slow or it will grind away. not sure of the limit but I have done it a few times and it is very bad.

[mitch_prest]

run it too low and you will break the bit... speaking from experience...

[ironsides]

I was thinking of hole drilling, when I asked about the lower RPM's.

I don't intend to buy a drill head and so I expect to do some hole drilling <.50 dia using the spindle.

George

[mitch_prest]

depending on what else you are doing at the same time.. you could just as well put in a 1/4" bit and use it both to cut out and drill ... you won't need to drop the spindle speed to do that..

mitch

[ironsides]

Confession is good for the soul!

Because the SB is still at the factory, I have been thinking about what the Deck material should be when I take delivery.

I plan on strictly mechanical clamping of the work. I plan on using two 1.75 X 24.0 X 48.0 Maple block slabs (Butcher Blocks) as the Deck material.

I plan on drilling a series of 29/64 dia holes thru the slabs and installing .375-16 "T" Nuts on the bottom to hold the work pieces.

This means that my first job will be drilling hundreds of 29/64 dia holes in the Deck, so using a bottom cutting end mill is out of the question.

George

[cnc_works]

George, you have just described the system I have used on my PRT96 for the last several years. Yes, there have been times I would have liked a full table vacuum system, but they have really been very few and very far between. I have built a purpose focused vacuum jig from time to time and that has worked just fine.

I have a 2" between holes pattern throughout my 48" x 96" and it has been a very useful and functional hold down method. I cut the pockets and the through holes for the t-nuts from the bottom of the sheet, then flipped it over, fastened down to my 1/2" aluminum base, then aligned and just cut holes through another piece of mdf to match the first sheet, and glued it down. Now I can surface it as often as I want and when it comes time to replace it, I just have to cut holes in another blank piece of 3/4" mdf and glue it down again without having to mess with the t-nuts again.

Then with an assortment of various lengths of brass rod and some brass nuts and washers holding down slotted 2" x 1/4" aluminum bar I have a very flexible hold down system. Also, it is good to have some assorted sizes of mdf that approximate the height of your work piece for the opposite end of the aluminum hold down to keep it level. And believe me the brass/aluminum saves $$$ when you hit a clamp. The only thing I regret is that the holes are not through to the bottom, so I have to blow the debris out of them before use because it doesn't fall through. I'm use to that by now though, so no big deal.

Donn

8725

[gene]

Also if you run a spindle too slow it will overheat and stop until it cools down.

[cnc_works]

Sorry, I kind of hijacked the thread a little. Probably should have started a new one.

Donn

[ironsides]

Hey Donn,

Thanks for the image and info. Great minds run in the same direction.

I will post an image and results of my intention when it is finished on a new post.

I have two more weeks to wait for the machine.

It will probably be several weeks before I get the deck idea finished.

Thanks all for your remarks about the spindle questions.

George

[Gary Campbell]

George...
A couple of notes...

A bottom cutting end mill with a spiral down toolpath may be a better solution than simply drilling that depth with a drill bit. This puts much less load on the spindle than a drill bit would. Bottom cutting end mills remove material much faster at spindle speeds than a drill bit does at drilling speeds.

Large pieces of Wood, such as Maple ,may not be dimensionally stable enough to serve as a good machine bed if you are cutting parts that have an accuracy requirement. Maple is subject to fairly large movement with humidity shifts. This movement may be increased with the addition of "hundreds of holes" that are unsealed.
Gary

[gene]

Hi All,
I have a pattern that i cut , pocket and drill on a piece of 3/4 oak fibercore . When i cut this pattern the bit wants to burn the wood when in the drilling only. the plunge is 2 ips and i am using a 1/4 compression bit to a depth of .5" The bit cuts and pockets fine and feels sharp the rpm are set at 14000 , What do you think ? I even set the drill to be the first step in the sequence. this has confused... ( I know thats not hard to do though) Thanks

[knight_toolworks]

14000 may be too fast for everything. 8000 would be plenty for the drilling operation.

[beacon14]

Compression bits are not really designed for drilling and are notorious for burning when used for drilling. If you can stand for the hole to be slightly larger than the bit diameter, you can use a spiral plunge and get better results. Even if the hole is only a few thousands larger than the bit the spiral plunge makes a huge difference. A straight or downcut bit may also give you much better results, but both will also work better with a spiral plunge.