how do you get a spring pin out of a blind hole?

I got one of those Chinese knock-offs of the Baldor carbide tool
grinder and before I started using it, I decided to do something
about the very visible runout in the backing plates. (0.045" TIR
in one and after that, I didn't bother to measure the other.) So
I took it apart and discovered that the backing plates have nice
keyways, though they're an odd size, about 6.2 mm wide (but under
0.25", though it'd be easy to file a key down) and 2.7 mm deep.
But the motor shaft didn't have any keyways -- all they'd done was
to drill a blind 6 mm holes and push in little stubby spring pins.
On one shaft the pin sticks up 1.7 mm, on the other just 0.6 mm.
So how do I get the spring pins out? There's not enough to grab,
and the only idea I've had so far is to grind away at them on the
inside with a carbide bit in a Dremel, and that'll be slow going.
Once they're out, I've got a long 3/16" milling bit, so I expect
I'll bolt the motor down on my mill/drill, lock the shaft with a
clamp, and cut proper keyways.
Anyone have ideas about removing the @#$% pins?
BTW, I turned down the backing plates on a mandrel. Back on the
grinder, the worse of the two has
Reply to
Tove Momerathsson
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"Tove Momerathsson" wrote: (clip) Anyone have ideas about removing the @#$% pins? ^^^^^^^^^^^^^^^^ We're talking about roll pins, right? The first idea that comes to mind is this: With a small drill bit, go down through the roll pin hole, and out the other side of the shaft. This will locate the center line for you. Now drill back from the other side, to open up a hole that you can drive the drill pin through.
Reply to
Leo Lichtman
> I got one of those Chinese knock-offs of the Baldor carbide tool > grinder and before I started using it, I decided to do something > about the very visible runout in the backing plates. (0.045" TIR > in one and after that, I didn't bother to measure the other.) So > I took it apart and discovered that the backing plates have nice > keyways, though they're an odd size, about 6.2 mm wide (but under > 0.25", though it'd be easy to file a key down) and 2.7 mm deep. > But the motor shaft didn't have any keyways -- all they'd done was > to drill a blind 6 mm holes and push in little stubby spring pins. > On one shaft the pin sticks up 1.7 mm, on the other just 0.6 mm. > > So how do I get the spring pins out? There's not enough to grab, > and the only idea I've had so far is to grind away at them on the > inside with a carbide bit in a Dremel, and that'll be slow going. > > Once they're out, I've got a long 3/16" milling bit, so I expect > I'll bolt the motor down on my mill/drill, lock the shaft with a > clamp, and cut proper keyways. > > Anyone have ideas about removing the @#$% pins? > > BTW, I turned down the backing plates on a mandrel. Back on the > grinder, the worse of the two has
Reply to
tomcas
annael them then run a mchine screw down the middle and use aslide hammer to pull the pin out
or alternatly use a vise grip slide hammer and grab and pull
Reply to
WILLIAM HENRY
Three methods.
1) Turn a close fitting dowel for the centre of the roll pins. Squeeze some grease into the hole and tap the dowel in. Hydraulic action should lift the pin up. If the pins are slotted so the grease just escapes then this won't work.
2) Wind a close fitting tap into the pin and then grab onto that with a drill chuck and pull.
3) As long as the pins are flush or slightly proud which yours are, get an old hex nut which fits over them, tack the pins to the inside of the nuts with a MIG welder and then grab the nuts and pull. -- Dave Baker
Reply to
Dave Baker
Cut a couple of sheet metal squares about the size of postage stamps. Punch a small hole in the center of each of them that just barely fits over the pin. Gas weld the pin to the sheet metal. Then weld a nut to the sheet metal. Then thread a bolt into the nut and pull it out with Vise-Grips. Easy money. - GWE
Dave Baker wrote:
Reply to
Grant Erwin
----- Original Message ----- From: "Grant Erwin" Newsgroups: rec.crafts.metalworking Sent: Tuesday, January 31, 2006 12:12 AM Subject: Re: how do you get a spring pin out of a blind hole?
Grant,
I thought you were going to comment on last words in that sentence. This last statement has me spraying coffee all over the screen and keyboard.
But I have to say, excellent advice on taking out a roll pin/spring pin.
But I don't think pulling on the nuts will help any. ;-)
Bernd
Reply to
Bernd
> > Tove Momerathss> > I got one of those Chinese knock-offs of the Baldor carbide tool > > grinder and before I started using it, I decided to do something > > about the very visible runout in the backing plates. (0.045" TIR > > in one and after that, I didn't bother to measure the other.) So > > I took it apart and discovered that the backing plates have nice > > keyways, though they're an odd size, about 6.2 mm wide (but under > > 0.25", though it'd be easy to file a key down) and 2.7 mm deep. > > But the motor shaft didn't have any keyways -- all they'd done was > > to drill a blind 6 mm holes and push in little stubby spring pins. > > On one shaft the pin sticks up 1.7 mm, on the other just 0.6 mm. > > > > So how do I get the spring pins out? There's not enough to grab, > > and the only idea I've had so far is to grind away at them on the > > inside with a carbide bit in a Dremel, and that'll be slow going. > > > > Once they're out, I've got a long 3/16" milling bit, so I expect > > I'll bolt the motor down on my mill/drill, lock the shaft with a > > clamp, and cut proper keyways. > > > > Anyone have ideas about removing the @#$% pins? > > > > BTW, I turned down the backing plates on a mandrel. Back on the > > grinder, the worse of the two has
Reply to
Tove Momerathsson
> >>Tove Momerathss>> >>>I got one of those Chinese knock-offs of the Baldor carbide tool >>>grinder and before I started using it, I decided to do something >>>about the very visible runout in the backing plates. (0.045" TIR >>>in one and after that, I didn't bother to measure the other.) So >>>I took it apart and discovered that the backing plates have nice >>>keyways, though they're an odd size, about 6.2 mm wide (but under >>>0.25", though it'd be easy to file a key down) and 2.7 mm deep. >>>But the motor shaft didn't have any keyways -- all they'd done was >>>to drill a blind 6 mm holes and push in little stubby spring pins. >>>On one shaft the pin sticks up 1.7 mm, on the other just 0.6 mm. >>> >>>So how do I get the spring pins out? There's not enough to grab, >>>and the only idea I've had so far is to grind away at them on the >>>inside with a carbide bit in a Dremel, and that'll be slow going. >>> >>>Once they're out, I've got a long 3/16" milling bit, so I expect >>>I'll bolt the motor down on my mill/drill, lock the shaft with a >>>clamp, and cut proper keyways. >>> >>>Anyone have ideas about removing the @#$% pins? >>> >>>BTW, I turned down the backing plates on a mandrel. Back on the >>>grinder, the worse of the two has
Reply to
tomcas

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