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02-05-2006, 11:30 PM #1
I have another stupid question! I cannot remove two roll pins (also called spring pins) from a casting.
The casting weighs about 250 lbs (cast iron), and the roll pins protrude about 1-3/8" from the side. They are 3/8" in diameter and about 2-1/2" long - too hefty for a wimp like me to remove, apparently! I have tried a vise and visegrips to compress them without luck. Don't think heat/cold will work. My old auto body puller will not grip them tight enough. Cannot get at them from the back - in blind holes.
Can they be drilled out? Is there a better way? They need to come out so I can remove bolts to a sub-assembly. They are super hard and in there tight!
Thank you all for your responses. I have learned a LOT from this great source! A.T.
02-05-2006, 11:35 PM #2
Most of the time you just use a flat nose punch that is just smaller than the hole nd drive the pin out. You man need to use oil if you can a some heat will hepl sometimes. Mel
02-05-2006, 11:45 PM #3
I agree with Mel,use a punch a little smaller than the diameter of the pin and drive it out.
Spring pins are hard and will not compress with a visegrip like you are trying to do.You could drill it out but I recommend using a carbide drill,again just a little smaller than the your hole diameter.
02-05-2006, 11:51 PM #4
Thanks, guys! However, each of the darn things is in a blind hole, so I can't drive them out from behind. Was afraid to use a carbide drill - the pins have a split down them which would (with my luck) probably shatter the carbide in the hole - then I would really have a problem!
I considered drilling a 1/8" hole crosswise in one, inserting a pin, and jury-rigging the auto body puller to bang it out, but there must be an easier way! Is there another way? A.T.
02-05-2006, 11:53 PM #5
Make a 1/2-13 slide hammer. Use the 1/2-13 on a pair of Vise grips instead of the knurled screw. Clamp the Vise grips on the pin and reverse knock them out.
02-05-2006, 11:59 PM #6
They are in blind holes guys.Take a die grinder or a dremel and grind a notch in the pin. Then put a peice of threaded rod a couple of feet long in the adjusting screw hole of a pair of vise grips.Clamp the pin with the vise grips, capturing the notch.Slide a peice of bar stock over the rod,put on a nut and slap hammer it out.
02-06-2006, 12:00 AM #7
traytopjohnny - Thank you very much - this makes me think I will somehow attach that body puller (I do not weld) to the end of each pin and whack it out - it is like a "slide hammer", I think.
Thanks again! I have enjoyed your posts here - great to have someone to ask who has really "been there and done that"! A.T.
02-06-2006, 12:05 AM #8
Pepo - that is a great idea! I will try it tomorrow and report back! Have to go home and feed the dogs - done for the evening. Thank you! A.T.
02-06-2006, 12:16 AM #9
It only takes a few minutes to make one of these:
(That's a bitty 6" vise-grip I didn't have a lot of real use for).
02-06-2006, 12:22 AM #10
I have made some fixtures to pull dowel pins, with an OTC slide hammer. I take a piece of 1 1/4 round stock, drill & tap to fit the shank of the slide hammer. Then, on the other end, I bore or ream to just fit the offending pin. then drill & tap 2 or more holes to use SHCS's on the side.. use at least 2 , at 90 degrees apart, 4 is better. Use Socket heads,you can tighten them better than set screws.. Put it on the pin, & tighten, then take it off & grind a small place , where the screws can bite in.. Put it back on & start pulling... Every few strokes, re-tighten the screws...
Impact is amazing, what it can do... a few years ago, a job was brought to me, a slide was stuck in a die. The next choice was to EDM the entire slide out, & remake it..I built a jig to grab it, so I could hook it to a slide hammer. After a day of using the slide hammer, I got it loose... That job paid very well.. [img]smile.gif[/img]
02-06-2006, 01:11 AM #11
If the roll pin is protruding (I think it is) you could also braze or weld your slide hammer shaft to the pin, after you get the first one out, cut off and re-attach to the other one.
02-06-2006, 02:00 AM #12
Try filling with grease then ,use a punch that will be a snug fit in the bore of the roll pinto plug the end .Wack the punch compressing the grease in thepin hole .It should move the pin out of the hole .You may have to add more grease and try again. should work.
02-06-2006, 02:32 AM #13
aside from using a tap burner, the quick welding of the slidehammer shaft to it may be the next best thing. the grease will squirt out everywhere tryng the hydraulic approach because the pin has a slot the whole way up the side. heating with an electric arc carbon will remove the temper from the pin and possibly allow it to release its spring tension, if you have a heating carbon small enough to enter the center of the pin, might try heating that way and then pull with the slide hammer. ( hint, a pencil lead -from an artist pencil made to hold those large leads-is used for this carbon in a pinch but it can be tricky/messy due to fragility and lack of copper coating. artist or engineer leads can be gotten easily from office and engineer supply stores. if you have the patience to wrap it in .002 brass shim stock you might get a passable miniature heating carbon. otherwise , if you heat say an inch of a length of proper diameter drillrod to bright orange and then insert quickly into the bottom of the pin, its heat will warm the pin, 4-5 fast heats may release enough spring temper to allow it to start moving especially if you keep the protruding end warm to prevent heat escape. let it cool and then try tackwelding something to it (like a nut) and use a screw type puller or a slidehammer puller. once you tackweld the nut to it, you can set up the screw puller and put some tension on it, then heat the outside part of the pin with oxyacetylene or air-acetylene and crank up the tension to get it to move.
'nother method, if any of you have used the redhot nut trick to remove frozen rusty nuts you will recognize this. take the rod clamp of your 200 amp lincoln buzzbox and clamp it onto the pin, ground the part, turn the box on for a short time like maybe 3 seconds on a midrange setting, just until the pin gets red hot, then shut it off. now the pin should draw out easily because it has no temper left and any adhesive or rust binding in there is now broken down.this is a shorcircuit for the box so its not good for more than a few seconds but usually doesnt take long to heat the item.
there's more methods but if these above dont work, you should just anneal it down to as soft as possible and go in with a carbide or cobalt drill until you get the diameter of the shelldown to where you can pull it out.
02-06-2006, 03:13 AM #14
ttok, yes, there is a better way to remove roll spring pins from blind holes.you will need to make a special tool though. i doubt that a slide hammer will remove them. this is probally the only way to get them out AFAIK.you will need a piece of flat stock approximately 3/8 inch wide, maybee about 1/16 to 3/32 in thick and about 6 inches long(little bit longer would be better)kind of like tool steel or just good strong steel.find center and bend to make a 90 degree elbow(like it was going to be a shelf bracket) now grind a taper on just one of the legs so that it is sharp(pointy) at the end and the taper point would end just before the elbow.you should have a piece that tapered on the wide side of the material.now what you will need to do is insert the sharp pointy end into the spring roll pin. it should not bottom out before it it gets tight. now since i do not know which way they are inserted in there, you will need to determine which way they are wound.the object is to wind(turn the tool)into the spring in the direction that will make them collapse and at the same time apply a sideways and extracting force on the tool(clear as mud-huh?)the spring roll pin should collapse and withdraw from the hole. http://i16.photobucket.com/albums/b7...f/IM000797.jpg sorry, i do not have a scanner and this was the only way to post a drawing. if you cannot make it out, let me know.
02-06-2006, 05:46 AM #15
The hydraulic method is elegant, but the split gives a way out for the grease, as mentioned. You could try packing the hole with wax, then use the close-fitting punch to 'compress' it out. Some will still want to escape through the split, but there may be enough action to push the pin out.
02-06-2006, 06:39 AM #16
Spring temper steel can be drilled. Use a good drill, cobalt steel is best. Slow speed, lots of lube and pressure on the drill bit. Remenber the pin is hollow, that will help guide the drill.
The pin may pull out, it depends on how it was fitted. If it took a hammer to drive it in, it would take a hammer to drive it out. It is hard to exert as much force backwards as forwards
02-06-2006, 07:39 AM #17
I used to be told by a toolmaker that the drawings I proudly gave him were "mud maps" - I have no hestitation in sharing this honour with you as well
02-06-2006, 08:12 AM #18
Another last etremety is to widen the claw of a cheap prybar, votch the spring pin a little on each side and drive the claw onto the spring pin tapping the bar with a small ball pien to keep the clay engaged as you lever the pin out.
The roll pins that have a double roll (their end section has about 1 3/4 turns of strong steel like a cinnamon roll) can be particularly difficult to draw. The best solution for these is to heat the exposed end to a dull red for a few minutes until the heat wicks down to the buried end and relaxes the pin's temper and tension. When cold the pin should draw right out.
02-06-2006, 09:40 AM #19
Temper the pin on the end, thread it with an old tap just a bit on the start, insert a screw which has the thread machined off the bottom
02-06-2006, 11:53 AM #20
since this is a big pin you can work from inside it. take a bolt a little smaller then the inside diam. grind the head off flush to the thread diam except for about 90 degrees of the head. (This works best with a carriage bolt). work the bolt, headfirst into the pinhole. Work the end under the end of the pin, assuming here the pin is not bottomed in the hole all the way. Put a washer and nut on the bolt and attach a slide hammer, use a prybar etc to pull it out.
Other way is a length of all thread and a couple oval washers and a nut inside. But that needsa lot of depth under the pin, works well for bushing though.