Really good router bit. I've given mine a real punishment, deep cuts into rosewood and a hard mahogany and it still cut well. My bits were delivered extra fast. Probably the best 1/8 inch bit with more than 1/2 inch depth on the market.

water-basedcoolantfor machining

This is an investment! That being said, if you only doing one slab, I would recommend DIY build or having someone professionally flatten your project. I would hazard a guess that you would be saving for a fifth of the cost of this rig. I bought the dust shield with vacuum hose attachment and was disappointed on a few levels. Firstly, it's a gimmick that falls short of its intended purpose and although it may cut down a little of the waste being scattered in the shop, it does not work as advertised. Do your slab flattening outside or you'llbe vacuuming for days. Secondly the hose port fit is not standard for any shop vac, so you'll be needing some type of adapter. As for the router sled itself, the build is sturdy, and it does work as intended. However there is the minimal clearance issue. Even at its lowest setting, I still had to raise the work piece as the plunge depth of routers are limited. Also expect to clear debris (constantly) from wheel path as it collects and will hinder the smoorh and level tracking of the wheels Overall, it works. But I'm thinking I should have opted for the bearing rail system. I gave it 3 stars because that's where it falls in the overall rating. Average! These are my opinions from my experience. Your millage may vary. If I could send it back without the hassle. I probably would. I don't have the box, and the return policy says everything has to be in original unused condition, which is impossible after use.

Types ofcoolantused in machining

Lubricant-type cutting fluids are most effective at lower cutting speeds. They tend to lose their effectiveness at high speeds (above about 120 m/min [400 ft/min]) because the motion of the chip at these speeds prevents the cutting fluid from reaching the tool – chip interface. In addition, high cutting temperatures at these speeds cause the oils to vaporize before they can lubricate. Machining operations such as drilling and tapping usually benefit from lubricants. In these operations, built-up edge formation is retarded, and torque on the tool is reduced.

Only having used this tool a couple of times, I am completely satisfied with it's performance. I have used the bit to flush trim a few patterns in walnut and white oak. This bit moved right through the wood. The cut was very smooth. I am also happy that I will be able to turn / swap out the cutters.

Coolants are cutting fluids designed to reduce the effects of heat in the machining operation. They have a limited effect on the amount of heat energy generated in cutting; instead, they carry away the heat that is generated, thereby reducing the temperature of tool and workpiece. This helps to prolong the life of the cutting tool. The capacity of a cutting fluid to reduce temperatures in machining depends on its thermal properties. Specific heat and thermal conductivity are the most important properties. Water has high specific heat and thermal conductivity relative to other liquids, which is why water is used as the base in coolant-type cutting fluids. These properties allow the coolant to draw heat away from the operation, thereby reducing the temperature of the cutting tool.

Difference between coolant and lubricantautomotive

Lubricants are usually oil-based fluids (because oils possess good lubricating qualities) formulated to reduce friction at the tool–chip and tool–work interfaces. Lubricant cutting fluids operate by extreme pressure lubrication, a special form of lubrication that involves formation of thin solid salt layers on the hot, clean metal surfaces through chemical reaction with the lubricant. Compounds of sulfur, chlorine, and phosphorus in the lubricant cause the formation of these surface layers, which act to separate the two metal surfaces (i.e., chip and tool).These extreme pressure films are significantly more effective in reducing friction in metal cutting than conventional lubrication, which is based on the presence of liquid films between the two surfaces.

I had previously been doing all my slab flattening on a home made sled. It worked ok and it got the job done, but it had many limitations, some of which I didn't even realize until I started using the SpeTool sled. The first issue was that it had too much flex in the wood rails and would sag when I tried flatting slabs larger than about 20" wide. The second issue was the mess it made in the shop. It was actually so bad that I would have to use it outside. The biggest draw back however, wasn't realized until I started using the SpeTool sled. With the SpeTool sled I was able to work the router with the grain down the long side of the Slab This was something that I couldn't really do with my homemade sled. Working with the grain produces a smoother surface and is less work in my opinion. Then when you add in the dust collection, I was able to work in my shop again. Now I am not going to say you won't need to vacuum when you are done, but the mess is drastically less than with no dust collection. Also, the aluminum rails are much stiffer than my wood ones and don't flex nearly as much over larger spans. I would absolutely put this kit at the top of my list if I was setting a small garage shop up for slab flattening. Rob @ RM Woodcraft llc