Drilled bushing

merlynr

Member
Couldn't get the zerk to take grease on the tilt ram of skidsteer so I took the zerk out and there was no hole to let grease into the groove of bushing. I took the pin out of the joint that holds the ram and the hole in the bushing was not aligned with the grease hole. So for a quick fix I decided to drill a new hole. Here's where the problem developed and after center tap to start the bit I drilled and drilled with no results and it dulled the bit. I center punched again fairly hard hit and even got a raised bump on the under side of the bushing Finally after using about ten bits and sharpening them I got about a 3/16" hole. My question is how can I center punch easily but couldn't drill easily?
ps some of the bits were brand new and dulled out at the same rate as my older resharpened bits. The new bits were gold colored.
 
Simple...center punch is harder than your drills. Thus the mark, but drilling is a no go.

Gold may mean TiN coated, base material may just be regular HSS or tool steel.

As stated try some cobalts.
 
Did you use lube when drilling? Did you drill at
fast speed or low speed? Low speed is best for
hard steels. Cutter angles on drill flutes are
also critical. The harder the material to be
drilled, the flatter the angle on the end of the
drill. Do not depend on the titanium coating to
hold an edge. Buy cobalt drills for drilling hard
steels. HSS drills will work, but only last a
short time in steel. Drill pilot holes (3/32, 1/8)
to save work resharpening larger drill bits every
time, and prevents the bit "wandering" before it
starts a straight hole.
 
Hardened steel don't drill easy.
Would've been easier to remove the bushing and put it back in with the grease hole aligned.
my 2 ct
 
Hello merlynr,

How slow you estimate you where drilling?
Remember that the harder the material you are drilling, the slower speed is usually best.
You found out by doing that it takes time and patience, when it come to drilling. Besides lubrication, speed and pressure are the key to success!,

Guido.
 
Was any part of the original bushing hole showing? If so, that will grab and break drill bits every time. Best thing to do in that case is use a carbide burr and high speed motor.
 
(quoted from post at 20:36:55 10/09/14) It would pay to read bisons post.
He got it right.
LOU
ou,..most people seem to prefer to do things the hard way :wink:
 

Some metals will "work harden" That movement of the hardened steel away from the tip of the punch can make it harder than it was originally.
 
(quoted from post at 13:04:42 10/09/14) Hello merlynr,

How slow you estimate you where drilling?
Remember that the harder the material you are drilling, the slower speed is usually best.
You found out by doing that it takes time and patience, when it come to drilling. Besides lubrication, speed and pressure are the key to success!,

Guido.
The speed of a Dewalt on setting 1
 
Look at a drill bushing catalog. Drill bushings are surface hardened to around 60+ Rockwell C hardness. Use a grinder to grind a notch through it rather than trying to drill a hole through it. If the bushing can rotate in the housing try to Loctite it in position or grind a notch around the O.D. so alignment isn't critical.

Grease holes, groves, etc are machined into drill bushings before they are hardened.
 
I always assumed a bushing was softer than the metal it protects cause it's a wear item especially in a dirty environment.
Someone commented it would be easier to remove bushing to reposition it. I think that would have been harder and if I removed it then I would have installed a new one. It was going to be easy as I was drilling where the removed zerk was, so just grabbed the drill and drill a new hole.
 
(quoted from post at 14:37:05 10/10/14) I always assumed a bushing was softer than the metal it protects cause it's a wear item especially in a dirty environment.
Someone commented it would be easier to remove bushing to reposition it. I think that would have been harder and if I removed it then I would have installed a new one. It was going to be easy as I was drilling where the removed zerk was, so just grabbed the drill and drill a new hole.
hese pin bushings are usually a steel backed outer shell with a bronze layer for bearing material.
If they where entirely made from soft material they would pound out in short order.
R&R these bushing ain't that hard if one uses a hammer and snug fitting pin with a step on it slightly smaller than the OD of the bushing
 
Hello merlynr,

That is about 450 R.P.M's lower speed ,about 100 R.P.M.'s or less would have made the bits last a lot longer. If the drill is turning even at 10 R.P.M.'s, with the proper pressure, it will cut. Speed kills when it come to drilling,

Guido
 

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