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View Full Version : High speed spindle with a Roto-Zip??



Hot Bob
02-08-2010, 02:55 PM
I need to do some work in brass using a 1/16" end mill. I'm thinking that a high speed spindle is in order here. I'm leaning toward using my Roto-zip which is variable speed 10k-35k I believe. Has anybody done this? I did a search but didn't turn up anything. Anyone see any reason it wouldn't work?

Bob

jacampb2
02-08-2010, 03:26 PM
Yes, it works, not quite as robust as a good palm router, but they work. See the digital machining section, I had a post about mine while looking for high speed spindle options.

Later,
Jason

BobWarfield
02-08-2010, 04:19 PM
Many species of aux spindle will work:

http://www.cnccookbook.com/CCHighSpeedSpindleAddOn.htm

Cheers,

BW

Doozer
02-08-2010, 04:29 PM
In a rotozip I don't think the bearings are securely mounted in the housing. I know inside a Dermel tool, the bearings are in a rubber sleeve in the plastic housing. Not good for precision location, but OK for a hand tool. Open up the rotozip and see how it has its bearings mounted.

--Doozer

derekm
02-08-2010, 05:12 PM
A trend T3/t4 router is quite easy to mount . The mounting point is rigid. The packge is small and the power more than enough 850w(over 1 hp!) speed varable upto 32,000 rpm and the price reasonable $130

http://www.amazon.com/Trend-T4EK-850-Watt-1-1-HP-Variable/dp/B001UQ5OX6/ref=sr_1_1?ie=UTF8&s=hi&qid=1265667069&sr=8-1

The router motor is easily dismountable from the router plate

Hot Bob
02-08-2010, 05:24 PM
In this case the work really doesn't need great accuracy. I already have a roto-zip that has been sitting doing nothing for years so I'd like to use it. I'm already bad enough about going out and buying new tools every time there's a chance I might use them.

Bob

Doozer
02-08-2010, 05:34 PM
It is not about needing accuracy or not, the spindle is going to be loose and it is going to chatter like a bitch. Using your rotozip just because you have it around and don't use it for anything else is not a good reason to mount it to your mill. If you don't use it, it is a SUNK COST. If it will not work well for what you want, and you use it for that anyways, that is foolish.
But do check the bearing mountings. It might be OK.

--Doozer

jacampb2
02-08-2010, 06:17 PM
I went through two rotozips before I bought the palm router. The first one, a first generation rotozip worked remarkable well but I normally had to rebuild it w/ new bearings every 1-2 months. It is not meant for constant use. The bearing arrangement is like this, the lower spindle bearing is constrained in the case in a molded pocket, it has a snap ring and is pressed on the shaft. The upper bearing is in a rubber sleeve and IIRC has a snap ring holding it on the shaft, it is also in a molded pocket, but the rubber sleeve allows it to float around a bit.

The second rotozip was a new model "craftsman" branded one, and I rebuilt it at least twice before I bought a palm router, it had the exact same bearing design, and even the same bearings. I only replaced the first because I drove it through the mill table and bent the spindle...

Anyhow, the design has virtually no runout (it really can't at 30K RPMS) but it does have a bit of end float. It never posed any problems with the acrylic engravings I do, but it did show up when milling PCB's. The bearings are just common electric motor grade bearings, so they don't stand up real well to high RPMs, I probably ran mine about 10-15 hours a week, and I think that is why I saw such a short life span. I replaced it with a Bosch Colt palm router, and that is a much better tool, but it still has a little bit of float in the Z axis. I eventually built my new high speed spindle that is belt driven by a full size router and seems to be a lot better.

Later,
Jason

darryl
02-08-2010, 06:22 PM
This is probably deviating a bit, but we once used a die grinder a lot. It was a Makita, and a good machine. I've considered using dremels and the like, then always wondered if this wouldn't be the better tool to use. The output shaft is supported on its own two ball bearings, and isolated from the motor itself by a drive coupling. I think you could grip the business end of it fairly easily and have a fairly solidly controlled output shaft. Might be something to keep an eye out for at garage sales, etc- I think it's a cut above when it comes to that kind of tool.

I would definitely check the integrity of the bearing mountings on that roto-zip. Maybe you could fill cavities with epoxy, or something, to enhance the rigidity of the bearings in it. I've never had one of those apart, so I can't say how good they really are, but it might be fine for your application. What is the size on the business end- will it take 1/4 inch shafts, or are you limited to 1/8 inch?

I agree with others- a laminate router or other palm sized machine with the 1/4 inch collet would be the better choice, but it's also a matter of play in the shaft. A larger machine with sloppy bearings would probably be a worse choice than a smaller capacity one with tighter bearings.

jacampb2
02-08-2010, 06:40 PM
The rotozips used to only come with a .125" collet, but they sell .1875", and .25" collet as well as a .3125" (IIRC) collet for the newer models. My Craftsman one came with the full range of collets, I think it is under $20 for the set of rotozip ones too if the OP doesn't have them.

In all honesty, this was the only thing that I found the rotozip was useful for. I dinked around with mine for a bit when I got it, but it is like trying to freehand cut w/ a router w/ no base, it was more trouble than it was worth.

I have a Metabo die grinder and it is awesome, a bit more bulky than most of the options, but mine has two tapped holes and a flat machined on one side of the spindle housing. It would be super simple to mount, but I'm thinking the length might prove troublesome to mount and still retain all your Z travel.

Later,
Jason

studentjim
02-08-2010, 08:37 PM
Hot Bob, check your pm's

Hot Bob
02-08-2010, 10:21 PM
Just to clarify; this is for use on a manual mill. I just need to be able to run smaller EMs without worry that I'll feed too fast and break them. The setup would most likely not see more than a couple hours a month. I'm not trying to cheap out here but it doesn't make sense to invest a lot in this for what will be very limited use. Based on the feedback here, it sounds like it will work. The float in the z-axis won't be a problem on the parts I'm doing as long as it isn't over about .005".

Bob