Welding holes in pins

super99

Well-known Member
Let me begin by admitting that I am not a certified welder, I'm just a farmer welder that has been welding since I was a teenage and I'm almost 67 now. At work I'm a material handler but have
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been going in 2 hours early for a couple of years building carts, tables, fan mounts, etc for the machine shop. From time to time we have parts that are bad, poor laser cuts, holes drilled wrong, etc and I have been welding them shut and grinding them smooth to be reworked. Yesterday my boss came to me with 180 pins that the holes are drilled too big, can I weld the holes shut so they can drill them on the other end and not have to scrap the pins? I wasn't very optimistic, but told him I would try on a few and see what they looked like. I welded 10 pins, 6 were OK, 4 had pins holes in the weld when I welded the 2nd side. Kinda hard to get the wire down inside that small hole to fill it up. Almost impossible to grind weld off and have a round pin. I told boss we need the piece it goes in to in order to grind the pin so it fits. He is going to take them to the line tomorrow and see if they are usable like that. I hope they tell him to scrap them and run another order, we'll see. They are extremely paranoid about scrap cost because it looks bad on paper, but will spend 2 or 3 times the cost of the part to fix it on overtime, but that's OK. Big Business, go figure! Chris
 
Managers pay the most attention to the factors they are judged by.
Those factors determine their pay and bonus, if any.
 
You would have an easier time welding it closed if you had a small pin that fit the hole. Drive it in and weld over the ends.

The pin holes are the result of air trapped in the hole. The air expands with the welding heat and pushes out through the puddle.
 
Thanks, never thought of that. The hole takes a roll pin and the pins falls thru now, so just a few thousands over. If they want to continue, I'll ask them for some pins to weld in. Chris
 
Hello super99,

Just fill the holes with pins a bit below the surface. Even a 1/8 of a in should be enough. Then grind them. Try to keep the welding are closer to the work, also if you can increase your the amps a bit, Will help eliminating those air packets,

Guido.
 
The prior comment about looking at manufacturing costs in different manners is spot on. Lots of companies track scrap and are laser focused on that value so the accountants and the managers segregate (bury) costs to rework parts in a way that isn't immediately recognized. I always see this "accounting gymnastics" approach as a failure of the management team to accept the challenge of leadership and to do the right thing. Our plant would be doing a cause and corrective action review to figure out why they were drilled oversized and what needs to be done to assure that would never happen again.

How long will it take you to weld 180 of these? You will have some that need to be reworked after welding so let's say you are really welding 210 so what's the cost on that? No idea what these pins do but is a welded area going to compromise the function? Do you have to get them black oxide processed again?

I vote to scrap them and fix the process permanently.
 
Depending on the size of the hole, you could run a threading tap thru it and screw a bolt thru it and grind the ends off.
 
How about taking a welding rod the correct diameter after you knock the coating off. Drive it into the hole and weld the ends. Even a package of drill bits the right tight size. Stronger than the original pin and perfect fit. Just some ideas.
 
(quoted from post at 10:51:17 12/02/18) Yesterday my boss came to me with 180 pins that the holes are drilled too big, can I weld the holes shut so they can drill them on the other end and not have to scrap the pins?

They look like "plain steel" which means cheap to other more exotic material.
But the company bean counters have put the fear into those that decide how to fix the problem.
So the decision is to spend 10 times more to fix than to start over.
I am going to guess that the company has some sort of toothless Quality Control department that is powerless to over rule anyone and do the right thing.

For your sake, I hope the company last long enough to get your retirement out of them.
 
Are the pins round bar or tube? From the pics they almost look like tube. If round bar, fill holes with a similar grade rod leaving 1/4" for weld on tops. You will need to grind smooth and if the pin O.D. is critical, machining on the lathe will be required. If tube, cut new tube because any way you try to fill the holes will lead to issues inside the tube if the tube I.D. is critical. Even if I.D. is not critical, time spent repairing these will outweigh the cost of making new parts when tube is used.
 

I can't tell the size of the hole from the picture. However, valve guide knurling tools are used to decrease the I.D. of worn valve guides which are then reamed to size. For your application the reaming operation may not be required.

I have seen them as small as 5.5 mm however, they are available in inch sizes also. The tool is similar to a threading tap however, it does not cut but rolls up metal thereby decreasing the hole I.D. Just google, valve guide knurling tools, which should bring up a selection.
 
As moresmoke said put a pin in the hole close to the same size and weld it in,I have reworked lots of pins like that for the auto industry,(we did auto proto-types)I used a tig welder but you can get similar results with a mig.The air pockets are coming from the void inside so a filler rod of similar material will solve the problem.If you use Tig. leave it a little long and puddle weld,if using mig have it a little short and fill it.
 
Looks to me a no brainer to cut new pins from a piece of shaft and drill a hole than to try restore these worn-out pins.
 
The pins are round and solid, cold rolled I believe, nothing special about them. Their plan is to drill correct size hole in the other end of the pin, but they don't want the bad hole to show. We build electric forklifts, not sure where these pins go. The pins are 1/2 or 5/8 dia. and hole is about 1/8". Yes, it's the bean counters, we are allowed so many $$ scrap/month. When somebody messes up something big, they go bananas. Makes their budget look bad. Don't care what it costs to fix it, just don't scrap it!!! I'll let you know what happens with it tomorrow. Chris
 
If it is for something like a loader pin it will be weak and break at the pin hole. Best find out if they are for something critical.
 
Those parts will ALWAYS look like reworked parts, degrading the perceived quality of your fork lifts. 20 cents of cold rolled round bar and spending several Dollars to salvage. FIX your process problem that caused the holes to be drilled too large in diameter. SCRAP the bad parts in several batches, keeping the scrap Dollars under the level that irritates the bean counters.
 
Don't know a thing about your scrap parts. Somewhat amused (not really) at the way people like to blame the accounting department or accountant for everything that goes wrong. As a CPA of 29 years who worked in corporate accounting once and taught financial and cost accounting at the college, I can tell you that somewhere in that company (probably in a damp corner of the basement) there is a group of people (likely without a window in the vicinity) who can attest truthfully that s**t runs BOTH downhill AND uphill. They don't make up the numbers or the policies. They get told what is expected from above and they prepare a budget and relay it to the folks below. Since it is career suicide to rail about the boss excessively, the accountants get the blame by proxy. My one stint in big business was working for Mike Ilitch back when the store count was less than 1000 but growing like wildfire. The place was a sweatshop. You were salaried and they cared not if you ever went home. Directives would come down from the family and we would have to convey them to the area supervisors. Then we were darn lucky if HIS boss, who was in the meeting that decided the directive in the first place, didn't come up and read us the riot act about how impractical the policy is. And that folks, is why I am in private practice these 29 years. Not that it is much different! :)
 
I agree with others about A. - tell them to wake up and make some new ones, or B. put a pin in then weld.

But just for the hell of it, I'd try brazing. Heat the end up red - stick a brazing rod in, and just melt it in there till it's full.

But of course - with any heating/welding technique you're messing with the properties of that steel - if these pins are used to say, hold something heavy over somebody's head - I'd go back to option A
 
And as for grinding them smooth - if you don't have a lathe - use the poor man's lathe - chuck them in a drill press and hold a good clean flat file against them.

Not sure I'd want to do 180 of them that way myself, but ... if they really don't want to make new ones... better than doing them all by hand.
 

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