Cheap tools??! Don't do it!!

[johnbaz]

Hi all

A friend bought a small motor cycle (Midi moto!) that had a stripped thread in one of the bolt holes in the barrel that takes the head bolts, The previous owner had drilled/tapped to 10mm which was too large then to get a bolt through the cylinder head!!

He asked if I could make a threaded tube (Similar idea to a Helicoil but solid!) so I grabbed a few high tensile 10mm bolts from stores at work then centre drilled one in my lathe to cut a 5mm thread, easy enough but the taps that i'd bought were only carbon steel instead of high speed steel, The tap snapped as I was approachin the 20mm threading depth!!

I found another 5mm tap and tried again, That was a cheapo tap too so I found my old taps out (I think they're Footprint taps) anyhow, I could feel the difference when getting deep, The carbon taps flexed badly before they snapped, The HSS didn't!!

With better tools!!

Job done, His lad has been razzing round the garden like Eval Kneval ever since!!

Cheap tools are a false economy :roll:



John

 

[t8hants]

To be fair the carbon tap was telling you it wasn't happy trying to thread Ht bolts, and you get even less warning if a HSS tap is about to let go.

 

[lurker]

I could feel the difference when getting deep, The carbon taps flexed badly before they snapped,

John

You know what they say about a workman and his tools :roll:

 

[ColeyS1]

My workmate just snapped my m8 snap on tap going into stainless. It'll be replaced with a 'hall' branded one which seem to be as good as snap on

Sent from my SM-G900F using Tapatalk

 

[Rorschach]

Part of your problem there will also bee tapping depth, you don't need anywhere near that number of threads for strength, in future if you drill out some clearance the tapping will go much more smoothly. I forget the actual number of threaded needed for full strength, I think it's 3 or 4, generally I look at a nut for that thread, and tap the depth the same as the thickness of the nut.

 

[Bedrock]

In general I agree with the cheap tools aren't worth the money. Certainly, carbon steel taps and dies are the work of the devil - I cannot think of any use where they might be worth the risk. However, on one of my raids to Aldi last year, they had sets of 5 ring ratchet spanners for about £12. I was tempted, particularly as they would not have heavy use. When I looked at the manufacturers name, I found to my surprise that they were made in Germany, not China. So far, with the caveat of fairly light use, no problems.

 

[MusicMan]

What was the objection to helicoil inserts? They work very well, and are much less hassle.

Keith