Since I have had the need several times lately for a tool post grinder, I have decided to build one because a good one is wayyyy expensive.
I will start by making the spindle first, since it is the heart of the tool and must be of good quality. I intend to use the Broadley spindle design. It uses Belleville washers to set the 10 lbs. of preload on the angular contact bearings.
I ordered angular contact bearings ( the same bearings I used in my Bonelle grinder spindle). They have a 20 mm bore , 47 mm OD, and 17 mm wide. The reason for this bearing choice is because I can , and did, get a ER 20 collet chuck with a 20 mm shank and 5 1/2" long. MY SPINDLE IS ALREADY MADE FOR ME . The chuck is pretty hard and ground, but cuts ok using carbide tooling.
I put the chuck in an ER40 collet and threaded the end 28 TPI.
Next I made a steel nut to fit the chuck. The chuck is already sized for the bearings. I will relieve the center area. This is the easiest spindle I ever made.
I have ordered a piece of 2 1/4" OD round 12L14 steel bar for the spindle housing.
Keep watching.......
I will start by making the spindle first, since it is the heart of the tool and must be of good quality. I intend to use the Broadley spindle design. It uses Belleville washers to set the 10 lbs. of preload on the angular contact bearings.
I ordered angular contact bearings ( the same bearings I used in my Bonelle grinder spindle). They have a 20 mm bore , 47 mm OD, and 17 mm wide. The reason for this bearing choice is because I can , and did, get a ER 20 collet chuck with a 20 mm shank and 5 1/2" long. MY SPINDLE IS ALREADY MADE FOR ME . The chuck is pretty hard and ground, but cuts ok using carbide tooling.
I put the chuck in an ER40 collet and threaded the end 28 TPI.
Next I made a steel nut to fit the chuck. The chuck is already sized for the bearings. I will relieve the center area. This is the easiest spindle I ever made.
I have ordered a piece of 2 1/4" OD round 12L14 steel bar for the spindle housing.
Keep watching.......
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