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Redwood 
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Joined: 16 Jan 2012
Location: Ontario
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 Topic: drilling retapping Cast
Posted: 04 Oct 2012 at 9:04am |
Finally had the WC down to the bear bones where I can say demo is finally done.
Although I have been picking at repairs now I can set up to paint and restore. However the rear end needs some signficant repair. The four bolts that hold the drawbar supports on where dammaged at the end of its working life. When it was taken to be repaired, instead of being fixed it got welded on one side. I was going to leave it but have come too far. It will need to be cut off.
Sooo
once it is cleaned, how hard will it be to ream out the four holes and retap, Will it need to be mounted and bored wiith a slow speed drill? I've never Reamed out cast and certainly not a bolt this large. I hate to take it to a shop if I don't have to, I need to save that money for things like rubber and engine.
Edited by Redwood - 04 Oct 2012 at 12:52pm
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Dick L
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Posted: 04 Oct 2012 at 9:11am |
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It is cast steel not cast iron. Big difference. You will be drilling and tapping the same as in a bar of hot roll.
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Redwood
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Posted: 04 Oct 2012 at 9:22am |
Shows you how a conception gets stuck in your head sometimes. Call it cast enough times you forget there is a difference.
So with some machine lube/coolant and a hand drill I should be able to ream this out with some patience?
(by hand drill I do mean a hand heald power drill  )
Edited by Redwood - 04 Oct 2012 at 10:06am
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didgood
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Posted: 04 Oct 2012 at 9:57am |
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Not sure if it would work in this application, but I've had excellent results with heli-coils. The drill size is just over the original max thread diameter, so there's not a lot to drill out. Then tap with an STI tap and thread in the heli-coil.
Should work fine, but maybe someone has more experience in this application.
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Tracy Martin TN
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Posted: 04 Oct 2012 at 10:01am |
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Is there a flat surface to work from? A magnetic drill would help. Tracy Martin
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Alberta Phil
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Posted: 04 Oct 2012 at 10:51am |
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Are the bolts broken off in the holes, or are the holes stripped out?
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Redwood
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Posted: 04 Oct 2012 at 10:54am |
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One is broken , another the head is welded to the support so I assume I'll have to cut it leaving me in the same position for it. the other two I'm crossing my fingers. This repair happened because atlease two were stripped I believe. If I can clean the good ones I will. but two need the extra work
Edited by Redwood - 04 Oct 2012 at 10:58am
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Alberta Phil
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Posted: 04 Oct 2012 at 11:16am |
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I have had very good results by welding a washer on to the stub of the broken bolt, then weld a larger nut onto that by welding inside the nut and weld it full. Hit it with some parafin wax while its hot and let it draw into the threads. When cool, you can work it out with a wrench. You might have to work it back and forth quite a few times to loosen it up before it will screw out. It also helps with this process to drill a hole, about 1/4 inch in this case, through the center of the broken bolt before welding.
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Coke-in-MN
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Posted: 04 Oct 2012 at 11:23am |
Heli-coils or they make a insert that is like a bolt with hole drilled in it for bolt. It is like 2 size larger bolt you drill and tap new holes for then screw in insert , thread origonal size bolt into it. I repaired SS plating racks that used 1/4" bolt by threading to 3/8" then dril and tap a 3/8" bolt to a hole with 1/4" threads . Can do the same for any size - they do sell these in several places , the bought ones have lock tabs you drive in to lock in place or use permanent lock-tite on outside threads.
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Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.
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jeffsh
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Posted: 04 Oct 2012 at 11:28am |
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TIME-SERTS work very well
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CTuckerNWIL
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Posted: 04 Oct 2012 at 11:40am |
I'm not sure what size these bolts are but if you have the rear end free of everything else and can roll it upside down, it will be handier to work on. To drill out to the next size bolt won't take a lot of material out of a stripped hole but getting your hole square would be important. If you could borrow a mag drill, like Tracy suggested and don't have any place to mount it, you can use the good holes you have to bolt a 1/2 inch plate to so you have a solid square mounting surface. You might want to be careful of drilling deeper than original. After tapping with a lead in tap, run a flat bottom in the hole for max thread. Then to keep this from happening again, use a stud bottomed in the threads and put a nut on it 
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Redwood
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Posted: 04 Oct 2012 at 12:44pm |
I have the rear down to just the spindles and drawbar. Since the drawbar is welded. I need to sort that out first. I'll check on the drill. and price the shop. If I have to rent a drill I doubt the cost will be much higher to pay to have it done and I can drop it off and pick it up. Bolting on the plate is a good Idea if I can find a drill. I'd get a doner but then I lose the serial #.
I'm thinking I don't have enough of the right kinda tools. My wife probably just felt a cold shiver down her spine.
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SteveC(NS)
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Posted: 05 Oct 2012 at 7:08am |
I'd suggest you drill a pilot hole while you still have reference to the centre of the bolts, Drill 5/32" or 3/16", at that size it's not an arduous task with a hand electric drill. Then, if you don't succeed with Alberta Phil's procedure and have to drill out, you can drill with progressively larger dia. drills until you achieve the size you need.
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TedBuiskerN.IL.
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Posted: 05 Oct 2012 at 9:58am |
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The bolts should be 3/4-10, and heli-coils work very well if installed correctly, and seated before you try to bolt them up. Heli-coils will be stronger than the original thread if done right. I did this to a WC I pulled with for years with no problems.
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Most problems can be solved with the proper application of high explosives.
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Coke-in-MN
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Posted: 05 Oct 2012 at 10:04am |
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Rather than renting a mag drill us a couple welding magnets the kind with the 45 Deg edges to give you a 90 Deg guide to keep your drill straight in line. Center punch the old bolt and drill out . If your off slightly you can clean old threads out with a small punch ground to a cape chisel form. Once old hole is clean drill to new size for coil using the magnets again for guide.
Edited by Coke-in-MN - 05 Oct 2012 at 10:04am
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Life lesson: If you’re being chased by a lion, you’re on a horse, to the left of you is a giraffe and on the right is a unicorn, what do you do? You stop drinking and get off the carousel.
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BrettPhillips
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Posted: 05 Oct 2012 at 11:31am |
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I helicoiled the drawbar retainer holes on my C using a hand drill. I made an angle iron fixture that bolted to the tractor, and it had a block welded to it that the drill passed through (poor mans drill bushing). This kept the drill from walking off and also kept the hole square with the tractor. I had more time in making the fixture than in actually repairing the hole, but it worked really well and saved me from having to find another final drive. If you have access to a drill press, maybe you could make something similar?
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Redwood
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Posted: 05 Oct 2012 at 9:30pm |
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Redwood
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Posted: 05 Oct 2012 at 9:42pm |
Here is how it looked this morning. It got too damp to take any more soybeans off so started at it. the brace bolts (not OEM) both snapped, the to bolts on the right snapped. and the one on the left is welded in place. Nothin is going to go easy with this. It is hard to see in the photo be the brace on the left is welded to the cast. Only thin left to dismantel is the weld. I hope to cut it off tomorrow. I wish I could get it into the drill press. But even I a could I wouldn't know where to get a slowspeed bit (old cast belt drive) That would be perfect. I cant go the bolt on way all holes have something in them. I makeshift magnetic drill bushing might just work (drill guide) We will se how it goes
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Tracy Martin TN
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Posted: 05 Oct 2012 at 11:02pm |
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If you had a better rear end, I would just use it. Change your serial number to the one you are replacing. Probably be better off in the long run. Tracy Martin
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Redwood
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Posted: 06 Oct 2012 at 8:35am |
Tracy yah that would make sense. I but if this was about sense I wouldn't be looking into putting a few thousand into a tractor that will never be worth more then its weight in scrap lol. Other then the bolt issue the rear is in exellent shape dispite the looks in the photo. The drawbar itselkf is the worst thing on the tractor. the guts of the rear end is in real good shape. I may replace the gears on the final drive shaft as there is some wear but they are not bad. As for changing the serial number I'm the only one that cares about which serial number it is and changing the number won't fool me. Given the condition it will be in fine shape once its redrilled. I'm looking into the helical fixes to see if they are stronger but if not I have no problem with oversized bolts. But you are right about the better solution
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