I have a question for RAYF or nige or tomv, or anyone that wants to chime in; I have been working on boring my track hoe boom that I posted in a different thread, I'm down to 3 bores left and have started having problems keeping my carbides intact. I have even changed out drill units, thinking that my feed rate was too fast, I am using a variable speed Milwaukee at about 175 rpm, I've tried hss steel, I'm terrible at sharpening it though, I even bought some 80 degree replaceable bits, they last a bit, but fracture after a couple of inches. I have tried a skim cut, only about a 1/64th cut, Ive tried heavy cuts, about .126", slow feed rate, I'm at a loss on what to do next. Forgot, I even got different grade and rotation carbide and they didnt last long. frustrated in texas
What size tool are you using? I'm not an expert but I have found the biger diameter holds up better on the brazed tools I have used. Hope to here from the others with more experience
I'm using AL8 370 American Carbide cutters which are 1/2" shanks. The bores I'm doing are 5.221"
Ask your supplier about the grade of carbide he is selling you. You need a soft and tough grade not hard and therefore brittle. Carbide also needs a steady feed and constant load. At 175 rpm you might have trouble keeping an edge on HSS. Sharpening HSS is not rocket science. For boring you grind the end back away from the cutting point to give clearance from the wall of the bore.Grind the top of the tool down towards the back to give it a few degrees of slicing action. Grind the front of the tool so that the bottom is back a few degrees to give it some clearance as it presents into the cut. As long as you have clearance on 3 sides it will cut. You will soon get the hang of it
Ask your supplier about the grade of carbide he is selling you. You need a soft and tough grade not hard and therefore brittle. Carbide also needs a steady feed and constant load. At 175 rpm you might have trouble keeping an edge on HSS. Sharpening HSS is not rocket science. For boring you grind the end back away from the cutting point to give clearance from the wall of the bore.Grind the top of the tool down towards the back to give it a few degrees of slicing action. Grind the front of the tool so that the bottom is back a few degrees to give it some clearance as it presents into the cut. As long as you have clearance on 3 sides it will cut. You will soon get the hang of it
well, If I dont figure out anything else, I did figure out why the 2 cutters that tried Saturday shattered after such a brief time. I ordered some new carbide today and was talking to the tool guy about why they were so short lived. He said,"youre cutting cast arent you?" I told him"no, it's steel, and pretty high grade at that". He sold me a softer grade carbide Fri. I got a friend of mine also to sharpen a HSS cutter for me today,after I slowed my rotation speed slowed down its working like a champ! only turning bout 80 rpm though.
all said before is true .are you useing oversize bushing????? or was the hole weled first ?? and what was done to get it ready to bore ??
I'm doing a mix of both. the bores i'm doing now are for an oversize bushing. I have also been doing some weld build and bore to size. However, those I have pre bored to true the holes and remove gall, then weld build back.
HeavyEquipmentForums here is a link to what I have done with it so far.
the bushing if broke and shattered it will embad in the parent metal ????? on both prebore ??? and weld back ??? we use heat . and grind back but you must look at the bore after it is cleaned . the bushings can cost you a lot problems if embaded
i removed the original bearings by cutting them out, except the one that I'm now. It is all parent metal.