I've used the 2.2 KW water cooled Chinese spindle with good success for a few years. As Danny mentioned, the power at low RPM isn't very good. The largest cutter I use for machining is 1/4" and it's usually 1/8" or less, but I do use a 1.125" mortising bit to level the spoil board and it seems to tolerate that fairly well at a medium RPM (tradeoff between power and spindle wear from a heavier and larger diameter unbalanced cutter).
The electrical connection on top is a four pin DIN style connector but the quality isn't great. It works OK but before I used pliers to tighten the knurled collar more than hand tight, it worked loose. Nothing was harmed other than blowing a fuse on the VFD when something shorted, and of course if broke another one of those $35 1/16" Onsrud carbide O flute cutters. The 8mm tubing connectors are a bit low quality too but I used good quality highly flexible tubing and tightened the compression fittings to the Gene Standard (1/8th of a turn less than breaking) and haven't had any problems. The bearings were a pleasant surprise. Spinning the unpowered spindle by hand is smoooooooth. It feels nicer than the spindle on megabuck machine tools. They advertise German bearings. I had assumed that "German" was a company in the Guangdong province, but maybe not. If the spindle met your torque requirements over your RPM range, my biggest concern in your application would be keeping grinding grit out of the spindle bearings. At the price of the spindle and VFD combos on eBay, you could buy a spare spindle and bearing and still be many bucks ahead. The Chinese water cooled spindles are not the highest overall quality, but in my experience, it's got it where it counts and the value is hard to beat. For a CNC router, it's a lot better than bolting on a woodworking router IMO. On 6/23/19 8:39 PM, Danny Miller wrote: > Have used a cheap Chinese air cooled 18krpm 3kw spindle for years. > You must drive them off a VFD anyways. > > At 3000 rpm you have much less power. Well the torque is probably the > same but power=torque * rpm. > > The air cooled is cooled by a shaft-driven impeller, so fan rpm drops > to 3000 rpm too. At high torque, low-rpm loads, it will still > generate a lot of heat but get very little fan cooling. You can swap > with a DC computer fan or go with water cooled. > > Danny > > On 6/23/2019 5:41 PM, Andy Evans wrote: >> Greetings everyone, >> >> I wish to upgrade a dressing spindle in our EMC grinder. We >> currently have a very small DC motor turning a one-inch >> diamond-studded disc at about 1500 RPM, with fairly decent results, >> but my research indicates we may be better served with a much larger >> disc and higher RPM. We drive this dresser under the wheel with a >> contoured path to give us the form we desire. >> >> There are available dresser spindles in the neighborhood of $12K that >> are very good looking but we wonder if we can build something that is >> sufficient for our needs for far less. >> >> We are considering the common router/milling machine spindles on >> ebay, air or water cooled, in the 1-2 KW range. Most of these seem >> to be equipped with either an ER11 or ER20 spindle, and most are >> advertised as 18,000 or 24,000 RPM. Some of them tout multiple >> bearings. Some claim a range of 8,000 to 24,000 RPM. >> >> Since I would expect many on this list to have experience with these, >> I am seeking to find out if we can successfully utilize a 3,000 to >> 10,000 RPM range, and also if the ER mounts are integral or if they >> can be removed. >> >> Or, if there are better ideas for accomplishing this, or if we are >> crazy not to purchase the $12K solution. >> >> Thank you! >> >> Andy Evans >> Evans Precision Tooling Incorporated >> 541.990.2122 >> >> >> >> >> >> >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
