Discussion
I am trying to establish the thread size on the gear stick to have a new knob made up. I told the guy it was 5/16 inch unc as suggested by someone. He sent me a tester gauge, and this size is wrong. It could be that 5/16 UNC for esrlier Wedges. My car is late 1990 350SE.
Any suggestions please gents. I am stuck and need information urgently. Could it be 8mm thread? Any clues or suggestions most welcome. My Wedge is sitting in the garage with no knob!
Tony. TCB.
Any suggestions please gents. I am stuck and need information urgently. Could it be 8mm thread? Any clues or suggestions most welcome. My Wedge is sitting in the garage with no knob!
Tony. TCB.
mrzigazaga said:
Hi Tony...Is the tester too small?....When i checked the gear knob that came off of mine..(1988 350i) an M8 bolt fitted snugly into the thread...Try an 8mm nut on it to see if that fits and that should answer your question...Ziga
Hi Mark. Yes the tester is too small and seems to be the wrong thread. I'll get hold of a 8mm nut and try that on and see if it fits. Once I let the guy know the correct size, he'll make one up in no time. Also the thread on the gear stick is two inches long. How far into a two inch ball should I get him to drill and tap in threads? 1.5" maybe? or 1.75"? Thanks for the quick response Mark, only I'm a bit stuck and need to get this made and fitted.Tony. TCB.
mrzigazaga said:
Hi Tony...I just checked the original thread that you posted and again i have put 8mm when it was an M6 bolt that i tried..So its worth trying 6mm and an 8mm nut...The thread length on the original gear knob was 2" so it would probably be best at 1.75" depth..Ziga
I have just spoken to the guy making the knob and he says that 8mm is a very close measurement to 5/16 unc. So that size is about right as the nut sits on the gear stick but only turns once before it gets stuck. Therefore he thinks that the tread type must be wrong. He is now sending me various different nuts with different tread sizes to see which will fit. This is getting a bit like Cinderella. 6mm though I think would be far too small.This guy also makes and machines all sorts of stuff in his shed. He tells me he can custom make a lot of other things made from metal as he has a fully equipped workshop. It could come in handy when we are stuck for something. He is also very patient and helpful.
The only thing that would help me now is if anyone knows for certain the tread size and type on a Wedge gear stick.
Thanks for your help Mark. I'll let you know the outcome. I am sick of using these after market gear knobs with the three screws in the side that never fit properly.
Tony. TCB.
GV said:
ElvisWedgely said:
How can I re-tap a piece of metal that's already been tapped? that's like trying to discharge a cartridge that's already been discharged.
Tony. TCB.
I am sure if you applied the logic you will see there is answer in what I have suggested...Tony. TCB.
Tony. TCB.
Contrary to general belief it seems that the Wedge gear stick threads are not 5/16 unc, at least not on my Wedge. It also seems that no one knows for sure what size nut fits our gearstick. However, I am on the case and hopefully will find out what size the threads are, so as I can have a knob that I'll be proud of. I am in touch with a guy who runs a small engineering establishment known as 'Properknob'. I am confident, as the name suggests that he knows his stuff and that he will solve the problem without the need for changing grearsticks etc. So, watch this space, and once fitted, I will be posting a photo of my new shiny knob.
Tony.TCB.
Tony.TCB.
Edited by ElvisWedgely on Wednesday 5th March 18:43
adam quantrill said:
You mean the girth of the shaft??
Well as promised I have all the details in glorious technicolour... I thought I'd keep all the measurements imperial:
Looks like 20 tpi and 0.3" across the peaks of the thread.
Works out about 1.27mm pitch... so could be a very badly cut, undersize M8 x 1.25 Well as promised I have all the details in glorious technicolour... I thought I'd keep all the measurements imperial:
Looks like 20 tpi and 0.3" across the peaks of the thread.
PROBLEM SOLVED. Gentlemen, I would like to apologise to all that suggested the thread is 5/16 unc because it is indeed that. The tester I was sent 5/16 unc wouldn't fit and today I received the M8 and that wouldn't fit either. My knob guy said it couldn't be anything else as I sent him a picture of the shaft with a ruler next to it. As too many people were suggesting the inch theory and I thought the car is bit too early to be metric, I started toying with the idea that 5/16 unc has to be the one. Because the tester is not a nut, I couldn't get a spanner on it for leverage. Luckily, I had also ordred some 5/16 unc nuts on the bay and received them yesterday. I put that on the shaft and plenty of oil and worked the nut in. After a few turns I knew it was the right one and that the gear stick threads were knackered. 5/16 unc nut, plus plenty of oil, and wire brush on the shaft done the trick. The thread on the gear stick is now cleared and virtually re tapped. I can now put a new 5/16 unc nut on the gearstick and screw it on with my hand. Result. Once again apologies for doubting the people in the know who suggested it in the first place. I can now look forward to receiving my new shiny knob.
Tony.TCB.
Tony.TCB.
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