Bolt Size Help

   / Bolt Size Help #131  
Ok.
I'm kind of mystified why the 16 mm didn't work.

If I'm understanding right, you've tried 16 mm bolts an/or clean out taps in the common metric thread pitchs :
16 mm coarse = 2.0 mm pitch
16 mm fine = 1.5 mm pitch
16 mm extra fine = 1.0 mm pitch

plus 5/8" in both coarse and fine tpi.

So what does that leave?
 
   / Bolt Size Help #132  
Ok.
I'm kind of mystified why the 16 mm didn't work.

If I'm understanding right, you've tried 16 mm bolts an/or clean out taps in the common metric thread pitchs :
16 mm coarse = 2.0 mm pitch
16 mm fine = 1.5 mm pitch
16 mm extra fine = 1.0 mm pitch

plus 5/8" in both coarse and fine tpi.

So what does that leave?
Nothing
 
   / Bolt Size Help #133  
before starting with the tap to clean the holes I would make a chaser with the 16mm 1.5 bolt that was given to you . Cut grooves in the bolt it will be less agressive than a tap.
 
   / Bolt Size Help #134  
before starting with the tap to clean the holes I would make a chaser with the 16mm 1.5 bolt that was given to you . Cut grooves in the bolt it will be less agressive than a tap.
Since he has the bolt, it certainly won't hurt to try that. A tap or chaser would be more effective. The reason he is having trouble starting a 16x1.5 bolt is the amount of paint that is in the holes. It may be difficult to get a homemade chaser to start too. Having started a career in machining in 1976 and having access to taps I've never
had the need to make a chaser out of a bolt. I wouldn't try to force it in the hole. Cast iron is prone to galling.
 
   / Bolt Size Help #135  
Two quick thoughts as it looks like this is about to wrap up.

If they are through holes, maybe try the bolts from the other side.

If they are blind holes, make sure you don't bottom out the tap and snap it off.

Doug in SW IA
 
   / Bolt Size Help #136  
Since he has the bolt, it certainly won't hurt to try that. A tap or chaser would be more effective. The reason he is having trouble starting a 16x1.5 bolt is the amount of paint that is in the holes. It may be difficult to get a homemade chaser to start too. Having started a career in machining in 1976 and having access to taps I've never
had the need to make a chaser out of a bolt. I wouldn't try to force it in the hole. Cast iron is prone to galling.

unless it's actually a different pitch of course. I guess it could be a 16x1.0 . Mcmaster-Carr sells that size in super strength alloy for high stress use.


You can make the chaser pretty nicely with a medium hard bolt, a bench vise, a fine cut hacksaw and a firm hand. Keep the slots vertical and straight so the cutting edge of the chaser will be sharp.

I angle the slots back about 15 degrees so that the chaser is partly self-cleaning. If you can make the slots so that they mostly miss the 2 or 3 tapered starting threads on the bolt then the chaser will start nicer.
But like any type of thread chasing, the real trick is to back it out and clean things up every few turns.
 
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   / Bolt Size Help
  • Thread Starter
#137  
I'm fortunate to work in a shop that is well equipped and will let me borrow things like taps. Don't be alarmed if your tap brings some metal out with the paint. I noticed on all the holes I have chased with a tap on this tractor the tap cuts a little in the very root of the thread. Good luck with your project.
Thank You Very much. I got a tap and ran it in the holes and cleaned them out and they work perfectly.
 

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   / Bolt Size Help
  • Thread Starter
#138  
Thank all of you who stayed with this post I have actually seen a lot of tools and gained experience from this and that is what this forums are about. Again thanks to all and it is confirmed for sure 16mm x 1.5 threads in case anyone else ever needs to know. also they are about 40mm deep.
 

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   / Bolt Size Help #139  
Maybe I missed it along the way. So what was the point of this exercise? Are you planning to bolt something to this assembly? Surely it wasn't just to plug a couple of open holes.
 
   / Bolt Size Help #140  
Glad you got it all figured out
 
 
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