Boring Oil Embedded Sleeve

Kroll

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Afternoon guys,I have several of these bushings to install in a QCGB.On some of them the bore was perfectly size which I did have to turn the OD down just alittle using a carbide insert.Then on another bushing the OD was correct but I needed to bore it out to match the shaft which is where he problem is.The bore needs to be just alittle over 1/2 .542 ID So I don't have a boring bar with an insert that small so I use a piece of 3/8x3/8 HSS and just made me a boring bar.The first pass was OK cause I remove most of the material.Next couple passing I was just trying to sneak up on the correct size so that I would not make a mistake like I did on the first one that I bored.Anyway while boring I notice that it was not removing hardly any material so I made couple more passes which I adjusted for about another .005 making .001 each pass.Still not removing any material and its boring at an angle.I can measure one end then measure the other and they are different.
When I was turning the OD on some I had made an arbor to fit the bushing on and it work perfectly,but when I switch cutting from carbide to HSS its just not cutting.It is i guess little dull but I was only taking .001 per pass.My other choice is I guess to buy couple reamers so that I can bore it to size,so what am I doing wrong here?
 
Are you sure that your boring bar has sufficient clearance and not rubbing on the bottom?

David
 
Good question I also though that,so I took a black magic marker and color the under side.After making couple passes,check to see if showed any rub areas.Nothing,its like it dull and the bar is pushing away even though I have everything tighten down.Going to give it a try again tomorrow which I will grind alittle to make sure bar is sharp.I'm already over size so try to figure out what I'm doing wrong
 
With HSS, run it slow, use a large nose radius, say 1/32 or slightly larger radius, hand grind, and hone the edge to a sharp edge. This should keep the edge from breaking down. Don't give it too much front clearance, too much will cause the edge to break down quickly. On your finish cut, once you get to the end, reverse the feed so the cutting tool comes out of the bore from the back to the front. Sometimes that will cut a tad more to finish.
 
Are your bushings bronze? they should cut easily with a sharp steel tool- you might need to heat and quench the tool to harden it more. Make sure it's on center or slightly higher and razor sharp
Mark
 
Thanks guys will dang I have grind it to a point,so tomorrow to the grinder first thing.Mark here what McMaster describes "Startup friction causes these porous bronze bearings to release a thin layer of oil on the bearing’s surface. They are also known as Oilite® bearings."
 
Thanks guys will dang I have grind it to a point,so tomorrow to the grinder first thing.Mark here what McMaster describes "Startup friction causes these porous bronze bearings to release a thin layer of oil on the bearing’s surface. They are also known as Oilite® bearings."
Oilite bushings need to be cut with a sharp cutter, or the pores of the metal get smeared over and no longer work as designed. If you have been rubbing on the bore (or the O.D.) of the bearing, then the bearing is ruined and you have to start over. When properly cut the metal looks dry and grainy because of the porosity. It it looks shiny, then it is no longer an Oilite bearing.
 
Might help if you showed detailed pics of your boring bar, Kroll. When you say the bar is not cutting, that means the cutting edge is not sharp or the geometry is knackered. Shoot some pics of the tool and I'm sure the guys can sort it out.
 
I recently bored a couple.
Just a nice new insert in the boring bar.
Joe Hynes

20180105_155858.jpg
 
That pic is a high load bushing from McMaster.
I used a regular oilite bushing in this pic. It is after boring and honing to size. They don't cut pretty, it is a crumbly chip but the cut is very predictable for depth.
Joe Hynes

20171219_185055.jpg
 
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