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I had a 'less haste more speed' moment.

The steering post head (an aluminum machined part) on my iceboat fits over the steering post (a mild steel tube) and is located by a roll pin driven through both. The drilled hole through both head and post isn't right on the axis, so you need to orient the head properly when you drive the pin in. If you're in a hurry (...he said...) and orient the head 180 degrees out of phase, the entry hole lines up and the exit holes don't. The roll pin drives in until it bottoms on the misaligned hole on the other side, and you can't get a drift pin into the misaligned hole on the other side to drive the pin back out. Ask how I know.

I couldn't grip the roll pin well enough to pull it out (if that is even possible), so I sawed off the protruding end and tried to drill out the roll pin. It's made of hard stuff! I make occasional progress, but it's mostly a case of ruined drill bits. The beastie is installed on the iceboat, so I have to use a hand-held drill instead of my drill press, and I can't get high enough feed pressure or a low enough speed.

I have thought of going in from the other side with a big bit, to expose the other end of the roll pin to allow me top drive it out with a drift, at the cost of having to drill a new set of holes through the head and post. This would be structurally acceptable, but an everlasting indicator of my original screw-up.

Any thoughts? It's something of a priority for me. It's the last step in assembling my new iceboat, which has been keeping me away from my Locost build. The iceboat season is starting, and more important to this forum, I'd like to get back to making progress on my car.

(PS: it's a 1/4 inch roll pin, so space is tight!)

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

Your idea of drilling the other side out so you can drift it out is with merit. As long as the strength of the part isnt compromised go ahead. One more thing though , if possible tighten a hose clamp around the roll pin so it cant fall out if you end up having made the hole a little looser.

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The biggest thing in motocross.

Do you have a spare roll pin to experiment with Warren?

You might be able to tap the inside of the pin to extract it with a slender machine screw.

Cheers, Ted

Can you leave it as-is, or is the rudder pointing the wrong way?

Or... you said it's a steering tube... can you cut the pin off by reaching down the tube with a hacksaw blade, then drive the short section remaining in the wall into the center where it'll drop off?

"If" you can get the assembly out of the boat...

Drill a new hole 90 deg to the old one and offset enough to miss?

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Thanks all.

To Ted, the tapping idea is a neat one, but I'd worry about breaking a tap and be in a worse mess.

For Kurt, I do have sufficient material to take another hole, so ultimately that is a possibility. Unfortunately, the tube is too small in internal diameter to get a hack-saw blade inside it.

Egoman, I'm facing up to drilling out the other end and drifting it out. As it happens I paid a visit to my local Home Hardware, which does have hardware. They not only had 1/4 roll pins, but 5/16 too: if I'm lucky (I won't say careful at this point) I may get a clean 5/16 hole through the whole works after I've got the pin out. There is enough material for the bigger hole, and no one (at least in the ice-boating circle) will be the wiser. Push come to shove I will drill another hole orthogonal to the first one.

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

I have pulled split roll pins out of cast aluminum housings by using a hardened drywall screw. The finer the pitch, the better. Try to screw it in as tight as you can. Then try to pry or pull on the head of the screw perpendicular to the axis of the screw. If you can get any bite into the rollpin, it should come out. I have successfully used this process this in ~1/8" (probably 3mm, maybe 4mm) diameter roll pins that held the exhaust ports in my rotay engine.

Alternatively, since your steering head is aluminum, you could Mig weld the inside of a 1/4 inch nut to the end of the roll pin and pull or work it out by rotating it back and forth using a 7/16" wrench. I've done this to extract broken bolts in cast aluminum too.

Good luck

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Chuck.

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Some years ago in a similar situation I went "dental" on a busted pin. I got a nice new diamond faced grinding bit for my dremel and attacked it with that. It was slow but easy cutting and didn't make too big of a mess. The diamond bit removed the piece of broken drill bit that was already in the hole. The bit I used was a tapered (pointed) end on a cylinder and I was able to get one that was about 1/3 the diameter of the pin, about 5/64"...they come in pretty small sizes. I figured if my dentist could do delicate work using that type of tool that it would work for me, and it did!

Bill

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Bill H
Winnipeg, MB, Canada

What Chuck said with the drywall screw. Use a hand screwdriver to screw it in unless your power drill can be torque limited, drywall screws snap easily. After you have the screw in as far as possible, clamp onto its head with vise grips and then tap the vise grips with a hammer to back the screw out.

This system also works with a regular machine screw tap. I had to make an extension for the tap out of a 12 point socket so that I could get the tap handle away from the collar.

If all else fails, Dremel two slots, 180 degrees apart, into the collar, then use a hose clamp to pinch the slotted collar tight to the shaft.

Good luck.

Tom

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Sometimes, I'm as confused as a baby in a topless bar.

My short term memory is absolutely horrible and so is my short term memory.

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If you have enough roll pin exposure to ruin a drill, why can't a pin punch be used?

Bill

Bill,

The whole problem lies with the hole for the roll pin not being on axis (well, the actal problem is my lack of care ... ). When I installed the head 180 degrees out of phase the tube and head holes on the 'exit' side didn't line up, so I can't get a punch in the other side to drive the roll pin back out - not unless I open up the hole in the exit side (which may be my solution later today). Had I been in les of a hurry, and used a punch as an alignment tool before driving in the pin, I would have notice the error before the damage was done, and all these options would have been moot.

The kluge solution might have been to just cut the excess pin off (which I did) and run with a pin on one side only. Hardly a safe solution for steering I'd say, and especially so after I have started thinning the wall of the roll pin by drilling.

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

slide hammer with a phillips screw in the end, screw it in and slide hammer it out from one side.

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Gotcha. Thought you WERE drilling from the back side. Talk about reading but not understanding!

Bill

Success!

I tried a slide hammer (dent puller actually) but the treads of the screw just stripped out of the roll pin.

So I crossed my fingers and drilled in from the other side and quite easily drove the pin out with a drift - one light whack and out she came. Looking at the roll pin, I had a lot more to carve away had I continued trying to drill it out from the other side. And I was in luck and was able to redrill the same holes out to 5/16" and simply upsize to a bigger roll pin. We're in business.

It struck me that it wasn't fair to fail to show you what I was doing.

First, for context, a picture of my old iceboat - doing about 30 MPH and accelerating towards 50 on the downwind leg to come. Then, the heim-jointed drag link that connects the bottom part of the steering post to the front runner chock (sorry for the fuzzy photo). And finally a view of the steering post head. The $^%((@#* little roll pin hole is the one on a fore and aft axis near the deck. The upper hole is where the mainsheet block ('pulley') attaches, and the tiller itself (which you can see in the first photo) is loosely in place.

Thank you all for your support.

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Warren
Isuzu Pickup/SR20DE, +401 COLD frame
Build Log: viewtopic.php?f=35&t=11601

i would suggest one of these next time...

http://www.google.com/products/catalog? ... gBEPMCMAE#

but hopefully there wont be a next time

See an aluminum chassis is just fine!!!!

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The biggest thing in motocross.