Hello welcome to Enots engineering I'm Alan
today's video I'm making some burnishing rollers that fit my knurling tool
this is my knurling tool and the rollers are just a plain roller with a good finish on
and these will burnish a diameter
we also look at how much the size is reduced when you burnish a diameter
so let's go into the workshop and see how we do it
this is my knurling tool and it works by clamping this down
the two knurling wheels clamp together
what I want to do today is make a burnishing wheel
which is exactly the same as a knurling wheel
except there are no teeth on the wheel
it's smooth and the idea is that as you clamp it on to the workpiece
it will give you a better finish than the turned finish
so to start off with I want to make two wheels the same size
I'm not sure what the material is
so if it's mild steel I have problems hardening it
ok I try to heat treat these but they're still soft so they're mild steel
the next job is to give them a good polish on the outside
so that they've got a nice smooth finish
so I've just got so emery cloth
I've put them on a bolt to hold in the chuck
take those off the bolt
so I will fit the wheels that we've just made into the holder
okay so this is the bar I've just turned which as a fair finish on it
not brilliant but say we wanted to fit a bearing on here
and we just and we just want to improve the finish
and I want to see whether these plain burnishing wheels
will actually improve the finish of that bar or not
I will put it on a slow speed
Tighten this it clamps them together
you can see it's starting to get a better finish on the very end
so I'll just do it a bit more and put a bit more pressure on
whether you can see how the finish is that is really smooth compared to this
so I think this would be useful if you're trying to fit a bearing to a shaft
and you come down near the size but you've only got maybe a 0.001" or 0.002" left
you know that when you've turn your tool in and take the next cut
it's going to take about 0.004" off
this would be useful because you could actual size it with the burnishing tool
to the right size
so I'll just do a bit more on there
and then we'll see how much in diameter the bar is altered
we'll measure that bar and see how much it altered
I'm just putting two slip gauges or gauge blocks there
just to support the bar
and I've cleaned the bar
so I'll roll the bar under this way first on the turned diameter
set it to zero
now I will turn the bar round and put the
burnished diameter on there
that's about 0.0004" down
so it's reduced the diameter but it's also given a better finish
a smoother finish lot smoother finish ideal for a bearing to be pressed on
but if I wanted to take 0.0003" of this diameter on the lathe
there's no way I'd get that finish and the right size
but by just running a burnishing tool over it
so what's what's happened with the finish
so if this was the surface of the metal bar
when you burnish it what you're doing is squashing all these ridges
compressing them down
so that you get an even finish over the surface
just compressing the ridges down to improve the surface
now if you could get some bearing races that would fit your knurling tool
they would be hardened on the outside last longer and give you a better finish
but for a piece of mild steel it's done a job
It will get you out of a jam
oh well that's it for today thanks for watching
I hope you enjoyed it hope it's useful and we'll
see you next time on Enots engineering