CBN and PCD inserts are very important cutting tools for resurfacing engine head and block, especially for round CBN and PCD inserts. Proper selection of the correct inserts and type are critical for engine rebuilding.
ToolingBox offers several different 3/8” and 1/2” IC negative rake inserts for the Surfacer machine. Below is a description of each.
A round 3/8” IC, double sided, Solid CBN Insert. NEWLY grade designed for multiple materials resurfacing. This solid CBN grade can be adapted to machining of various engine materials, including high hardness grey cast iron, hard steel alloy and even pure aluminum engine block. When using a 14” cutterhead speeds range from 900-1200 RPM. When using an 18” cutterhead (F80) speeds range from 600-800 RPM.
A round 3/8” IC, double sided, Solid CBN Insert. An excellent, long life insert for surfacing cast iron heads and blocks -round shape gives many cutting edges on each side of insert. When using a 14” cutterhead speeds range from 900-1200 RPM. When using an 18” cutterhead (F80) speeds range from 600-800 RPM.
(solid CBN inserts for engine resurfacing)
A round 3/8” IC, single sided, laminated PCD Insert. For use on aluminum only - heads and blocks without liners. This insert has a thin layer of PCD applied to a carbide disk. The diamond appears to be a shiny black wafer. The hardness of the diamond resists the abrasive nature of the silica in aluminum heads and blocks. RPM speeds with a 14” cutter range from 900-2000 RPM.
(Laminated PCD inserts for engine resurfacing)
A round 3/8” IC, single sided, laminated CBN Insert. For use on aluminum blocks with iron liners and aluminum heads with steel pre-combustion chambers. RPM speeds with a 14”cutter range from 650-750 RPM.
A round 3/8” IC, single sided, laminated CBN Insert. For use on cast iron heads with steel pre-combustion chambers. RPM speed with a 14” cutter range from 600-700 RPM and with a 18” cutter range from 500-600 RPM.
It is critical that the heads be mounted in the fixture correctly. If the head is not mounted in this way, the inserts will chip when they contact the sharp of the pre combustion chamber.
Note: There are at least two different materials used in the manufacture of the pre-combustion chambers. ToolingBox Manufacturing has experimented with only one of these materials and cannot guarantee cutting all materials.
A round 3/8” IC, single sided, laminated CBN Insert. An excellent job for cutting hard cast iron blocks and heads of a single material or bi-metal. Also is the best for compacted graphite cast iron heads and blocks refinishing and resurfacing, Diesel engine rebuilders. RPM speed with a 14” cutter range from 600-700 RPM and with a 18” cutter range from 500-600 RPM.
(Laminated CBN inserts for engine surfacer)
A round 1/2” IC double sided, Solid CBN Insert. An excellent insert for machining cast iron heads and blocks. Round shape gives many cutting edges on each side of insert. Requires the purchase of 1/2” negative rake tool holders.
A round 1/2” IC, double sided, Solid CBN Insert. NEWLY grade designed for multiple materials resurfacing. This solid CBN grade can be adapted to machining of various engine materials, including high hardness grey cast iron, hard steel alloy and even pure aluminum engine block. Requires the purchase of 1/2” negative rake tool holders.
A round 1/2” IC, single sided, laminated PCD Insert. For use on aluminum ONLY - heads and blocks without liners. This insert has a thin layer of PCD applied to the top of a carbide disk. The diamond appears to be a shiny black wafer. The hardness of the diamond resists the abrasive nature of the silica in aluminum heads and blocks. RPM speeds with a 14” cutter range from 1000-2000 RPM. This insert gives the maximum productivity when cutting aluminum. Requires the purchase of 1/2” negative rake tool holders.
A round 1/2” IC, single sided, laminated CBN Insert. An excellent job for cutting hard cast iron blocks and heads of a single material or bi-metal. Also is the best for compacted graphite cast iron heads and blocks refinishing and resurfacing, Diesel engine rebuilders. RPM speed with a 14” cutter range from 650-750 RPM.
2. How to choose inserts Qty? One Insert vs. Two Inserts
Normally the surfacer machines can be rum effectively with either one or two inserts installed in the cutterhead.
If two inserts are installed and aligned within .0001 of an inch the feed rate can be run 2 times faster than if using only one insert.
The depth of the grooves made by the inserts for a typical finish is approximately .0003in. Therefore for a second insert to be of any advantage in obtaining a smoother finish for a given feed rate or a similar finish at a higher feed rate the inserts must be aligned within .0003in. Aligning them within .0001in will give you a significantly smoother finish than aligning them within .0002in. Therefore for maximum quality and consistency ToolingBox recommends aligning the inserts within .0001” in a vertical plane, alignment of the horizontal plane within .002in is sufficient.
If aligning the inserts within .0001in is too time consuming we recommend mis-aligning them between .0003in and .0015in. With the inserts mis-aligned you will get the same finish for a set RPM and feed rate that you would using one insert. The benefit on using two inserts is for stock removal. Since the one mis-aligned insert is removing some material the depth of cut can be increased up to .010in and acceptable tool life obtained.
If one insert is used (50 percent of customers use one insert), you do not have to worry about alignment. It makes it very easy to change from CBN to coated carbide inserts. The following data assumes you are using a 3/8” diameter insert, either CBN or coated carbide.
(the surface of Aluminum cylinder of after rebuilding by laminated PCD inserts)
3. Cutting Speed Calculation
Inserts are designed to cut within a speed range (S.F.P.M.). In order to convert from cutting speed to RPM, use the following formula:
RPM = S.F.P.M. X 3.82
DIAMETER
S.F.P.M. = Surface Feet per Minute
RPM = Revolutions per Minute
DIAMETER in Inches
