Let's design a spindle!

[Cold Fusion]

I am interested, thanks to the advice of the board, in making a spindle capable of being driven by a Porter Cable router. This will probably be the best starting point as far as a motor goes because of the horse power and variable speed.

Now as far as the collet system and bearings, I really have no idea there. I would like to get the rpms down to a speed which will produce a proper chip load at slower speeds such as 10-15 ipm.

Of course I won't be able to machine a lot of this stuff, so if someone with a lathe is interested in helping out, please let me know.

Now comes the critical question. Do the more experienced machinists think that we can produce a spindle of higher rigidity and quality then the Porter Cable one available right now?

Enough ramblings for now. I'll start thinking about a design and get it in CAD so we can at least have something to look at while we theorize.

[Dan S]

CF

One quick question what is your first name? So I can stop calling you CF, its got to be getting old.

My first thoughts would be try and keep the spindle it’s self under 11/16” in diameter. This would allow it to be turned on a 7X12 mini lathe, which would greatly increase the number of people who can make them, or make one for you. It could be made out of mild steel, and use a simple collet system. I think if you try and design it to use off the shelf collets, it is going to get really expensive. A housing could be milled out of aluminum.

I think the real problems will come with trying to gear down the router safely, and finding bearings that are up to the task.

Can anyone else speak to this?

CF what cad are you using I use rhino2.0 and AutoCAD so we can exchange ideas if you want.

[JRoque]

Good one Cold Fusion! I also bought a Porter Cable router for lack of a real mill spindle. I like your idea of using the PC motor as drive.

Can't say much about how to get started but would think that an R8 collet is a good option. For a bearing, what about a car wheel bearing? Not sure how accurate they are but they can certainly take a beating.

By the way, is the 10K RPM of the router your only issue with using it as the spindle? If it is, we can probably work on a speed control that slows it down while keeping the torque. The PC is, after all, a brush universal motor when you take out the Atmel based speed control that comes with it.

Regards,
Julio

[Cold Fusion]

Hey Dan,

My name is Andrew McCalip. I have access to Rhino and Solidworks. How about we stick to Iges if possible? That way I can generate solid renderings easily with Solidworks.

Good thought about the size. Now here's a question back at you. What size end mills will we want it to accept? I was thinking no larger then 1/2". Will we use a compression collet or a set screw system?

I don't think finding the bearings will be a problem so much as making a design that properly uses them.

[Cold Fusion]

Julio,

It's not only the torque issue, but also of basic rigidity. Sometimes I can plainly see where router has sometime made the bit deflect resulting in poor cut quality.

[Dan S]

Andrew

I'm at work at the moment, but i will sketch some stuff out here on paper, and then throw it into cad when i get home tonight.

-Dan

[JFettig]

What about grabbing a mini mill front part head asembly and make a mount and pully setup and run r8 collets?

-edit- you can get these parts from littlemachineshop.com

I am currently making a new mounting plate and pully system for my 1.5hp motor Im putting on my mini I have been running it belt drive and I thought about doing this, grabbing a router and kicking up the speed a little more. The only thing is that the bearings in there can only handle about 7000rpm, I replaced mine with bearings that can handle 10,000rpm. If you look hard, maybe you can find some that can go higher than that. Right now I am running a 3/8" belt 1" pully on the motor and 2" pully on the spindle.

Jon

[DAB_Design]

If I can chime in with something....I wouldn't recommend an R8 taper. My machine has an R8, which is nice because they are readily available. But here are the problems I have with them. They are too long. If you have a limited Z travel, you'll run into problem with getting the arbors out of the spindle. Just a guess, but I think they are around 6-7" long(depending on bore diameter). I'll actually measure one later and post a few different lengths.

Second, the set screw type arbors are cheap, which is good. About $11 or so. But the collet arbors are more expensive. Looking on HF right now, they have a collet holder with wrench for $27 (no collets), and they also have a set of 1/8 to 5/8 with 1 holder and wrench for $83. To get a good set of holders and collets so that you aren't changing tools out all the time, would cost quite a bit.

I like the idea and would like to help with what I can, so I'll be lookin in on this thread.

What about an interchangable gear box or something like that. What type of reduction would the router need? I'm not too familiar with routers, but aren't they somewhere in the 10-15k rpm range?

[Cold Fusion]

Well, an interchangeable gearbox is not needed because the speed can be ajusted on the router itself from 10k-27k.

[Dan S]

After thinking about it, it will be simpler and easier to just by parts instead of making them. How about these? All that would be needed then is a way to mount it and get the power from the router to the spindle.

http://www.littlemachineshop.com/pro...ProductID=1508
http://www.littlemachineshop.com/pro...ProductID=1637
http://www.littlemachineshop.com/pro...ProductID=1948


The only other thing I can think of, is that we need a set up that won’t destroy the router so if we want to do work in wood or lexan, all we need to do it un-mout the spindle and mount the router. Maybe a pulley or gear than can be put into the router collet and then into the router


-Dan

[witold]

You can expect problems with heat! Even with only 10000 RPM heat build up can be quite significant. I am building spindle /not ready yet/ and because of overheating I already had to make many changes! Be very careful when it comes to choice of the bearings. Cheap ones will burn in no time.

[broken003]

anybody know where to get bearings that are rated over 10K RPM?