Ignoramus12820 fired this volley in news:34WdnVDmwp7NufDRnZ2dnUVZ email@example.com:
I know that the head on one of my vendors' CNC router - by itself - cost over $700.00. It is rated for 5000 hrs continuous duty at 45KRPM before requiring a bearing overhaul -- which is a factory-only job.
They claim it's good for five re-builds, minimum, if the chuck is never crashed into the work.
This "head" isn't a router in the conventional sense. It's just a motor with mount pads and a collet-style chuck on a fairly short shaft. Nothin' much to look at. But it's virtually silent running at 40K under no load. It runs on a dedicated speed controller, and is purportedly a multi-phase motor. The controller was extra $$, and misbehaved badly for speed regulation and control until swapped out twice by the factory rep.
Don't remember the brand, but it's the one the ShopSabre folks recommend for the machine.
Probably ok for continuous shallow duty. Notwithstanding, for 100 bucks how can you go wrong? You have 10x that in the holder/bracket and that great camera. Don't sweat it; if it blows up get a PC 690, known to run forever at medium duty levels.
Somebody is talking out of somebody's rear orifice. While you're not generally going to find one at the business end of a $100,000-$300,000 commercial CNC machine, where a $5000 spindle motor is not a big expense, tens of thousands of $2,000-$15,000 homebuilt or kitbuilt CNC routers run them with no particular problems.
Other than being LOUD due to the universal motors, quality wood routers can be used rather extensively. If you can arrange to feed it clean air (possibly force-feeding it - ie, put a duct and blower on it), so much the better. If you actually service/replace the bearings per schedule (IIRC Porter-Cable specs 100 hours on the 690) better yet.
CNC wood router folks have used them for quite a while - the folks with money do like to step up to much more expensive and powerful (and quieter) spindle motors, but in bang/buck the router does fine. I've run mine for hours at a stretch, and so have a lot of other folks with CNC routers. Even if you simply run it til it dies and replace, the bang/buck is good, but servicing it properly the bang/buck should be better.
Unless you have a specific need for the small size, pick a normal router over a laminate trimmer/palm router/whatever.
A 690 mounts nicely to a chunk of channel with a big hose clamp, by the way. Just take the base off.
Crapsman, B&D need not apply...
Get good, comfortable hearing protection - you'll need it.
In (non-cnc) router table service, it's not uncommon to switch one on and run hundreds of feet of molding though a router, so running them for hours at a stretch is not some oddity that only CNC router folks do. The cooling air on a 690 makes one heck of a breeze...
Yes. I was thinking about it as I was walking to work.
I realized that, say, 30,000 RPM is not that big of a deal for a small spindle on this Bosch Colt. It is not like it is a 2.5" Bridgeport spindle with huge bearings and huge linear speeds. The spindle bearings are probably 3/4" ID or there abouts.
The manual on it calls for a factory rebuild (read bearings replacement) every 300 to 400 hours.
If I can get 300, or even 200, hours out of it, this is all I really need. It is a lot of hours for a hobby use. Considering that a very fast head like this can complete projects very quickly due to high feedrates possible, 200 hours could complete a lot of projects. Similarly, because it works so fast, it would not need to stay running for very long, before it completes the assigned task.
I thought for a moment yesterday that I will use my big 2.5 HP router, but I am backing out of this, it is a little too big and there are complications with overhang, etc that would impact accuracy too much. Plus it is inconvenient to mount.
This Bosch Colt looks very appealing, because of ease of mounting, reasonable power, etc.
I think that I could use it with a 10A solid state relay, because, IIRC, it has a soft start.
Here it is 300 hours. Not really a problem.
Just what I hoped to hear.
What about something like this:
I think that it can be taken out of the base and then mounted in some kind of a round clamp. I have a CNC mill, so I can make an aluminum clamp that fits perfectly.
690 is something like this, right:
That could also work. Any comparison with the Bosch one?
Well, that is very nice to know right from the horse's mouth, so to speak.
You have compressed air available and the router will be fixed on the machine, so just adapt it for forced cooling air. Fabricate a manifold to introduce the cooling air (via a filter and a throttling valve) to the top intake of the router. You'll benefit both from the cooling action of the decompressed air, as well as a clean air source.
You know Pete, this is a good idea. It definitely needs a good filter, but it is a great suggestion. It may be that I can find a "turbine" for paint sprayers that would deliver more air at the pressure that I need, as opposed to a compressor.
After a lot of thinking, etc, I have decided to bite the bullet and bought this Bosch router:
Bosch 1617EVS 2-1/4 HP Variable-Speed Router
It is only marginally more expensive than Colt, and should be trivial to mount in a clamp, due to its round body. The speed range of 8,000 to 25,000 RPM is also ideal for me. Soft start is also a huge plus. It comes with a 1/2 and 1/4" collet.
I know of a few CNC's (General Gorilla) that use those 2.25HP (1/2" shank!!!!) Bosch's in school settings. Aside from the noise, they're holding up very well. Shopbot also sells a 3.25 HP universal motor PC router body that also seems to run quite well.... but they do offer rebuild-kits matter of factly. I run an Elte 3HP 3phase spindle off a VFD and it runs quietly and full power at any speed....and cool.
I have put 100's of hours on a PC 690, used for wood as well as high density polyethelene (hdpe) with 1/2" diameter bits running 3 inches/ second (60% cut, 1/4" max depth per cut).
Wore the brushes out, replaced them from the ShopBot spares kit, original bearings still working just fine. The dust collection does pull the exhaust air from the collet end (the only danger I saw was the sparks from brush end of life and fine sawdust mixing ... no fires or explosions, thank you very much.
I tend to run the 690 on the middle of the 5 available speeds ... no noise reduction, just adjusted everything for shavings per bit manufacturer.
I used to work in a place that used router tables to trim plastic. The routers were working continuously for up to three hours at a time. Only thing they ever needed was normal bearing replacement. Porter Cable 690 routers.