Is a 12 HP Colombo Spindle "Overkill"?

[tuck]

I'm thinking of upgrading to a spindle router, but the cost is a major concern. Looking on eBay for used spindle routers, I found these:

http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=spindle+router&category0 = (http://search.ebay.com/search/search.dll?cgiurl=http%3A%2F%2Fcgi.ebay.com%2Fws%2 F&fkr=1&from=R8&satitle=spindle+router&category0 =)

Man, he's got a bunch of them, but they are all 12 HP. The prices look right. What do you guys think?

[Brady Watson]

I think that while it's very appealing in the cost savings department, that it is not what you are going to want on a ShopBot for a few reasons:

1) You don't know the history of the spindle and may get one that needs rebuilding $$$

2) A 12HP spindle weighs quite a LOT more than a 3HP or 5HP one and you will need to seriously reinforce the Z's T-rail and add more V-rollers. You will need a 10:1 gearbox on an Alpha to be able to move the Z up as well as overcome the counterweight spring force. A standard 1:1 is not adequate.

3) You will need a 50 or 60 Amp 3ph breaker dedicated to the spindle alone.

4) You will most likely need to stiffen or replace the gantry supports to compensate for the increased deflection that the added weight will exert on the carriage in the center of the table in the Y direction.

5) You may have to slow speeds when cutting intricate parts and shapes due to the large increase in weight & rolling inertia (even with Alpha & feedback)

6) Your X, Y & Z rails will wear out much sooner than normal due to the increase in weight.

7) You will not be able to take advantage of the full 12HP on an Alpha since you can barely use all of the power in a 5HP when cutting at 10 IPS.

It's a false economy in my opinion...You are better off saving the money for a spindle in the 3-6HP range than using a 12HP one.

-Brady

[dirk]

I agree, also note that description states "needs bearings"

[tuck]

That makes perfect sense to me, Brady, and I don't even have an Alpha. Mine is a PRT about 8 years old! :-0 I'd might as well by a heavy-duty industrial CNC to make it work.

Thanks for your input.