Tread chaser question
Thread Starter
8th Gear
Joined: May 2018
Posts: 8
Likes: 1
From: Austin, TX.
Tread chaser question
Does anyone know what size bolt is used in the ends of the shafts in the upper control arms? I am wanting to purchase a thread chaser to clean up the treads before I reinstall the shafts and bushings. I thought I had remembered reading it was 5/16 X 24 but I wanted to be sure before I made a purchase. Thanks.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
on my 72 (s/b the same) it's a 9/16 wrench so 3/8 thread and I'm pretty sure they are fine thread so 3/8-24. (I believe the lower arm is 7/16-20)
I also don't know what year car you're working on so...
M
I also don't know what year car you're working on so...
M
Safety Car
Joined: Dec 2012
Posts: 3,815
Likes: 1,726
From: Summerville SC
You could also take one of the bolts over to Home Depot or Lowes and use their thread checker in the bolt department. I actually went and bought one of those things since I could never tell , especially with the metric sizes.
Thread Starter
8th Gear
Joined: May 2018
Posts: 8
Likes: 1
From: Austin, TX.
Thanks Mooser. You are correct about the lower bolts. I will take your word on the upper ones. At the worst, I've spent about 7 or 8 bucks, and will now have a new tap. I appreciate the quick response.
Kanvasman, you too are correct. I have thought it would be nice to have one of those to determine bolt and nut sizes and coarse or fine threads. I would need both the SAE for the vette and the metric for my pickup. Thanks.
Kanvasman, you too are correct. I have thought it would be nice to have one of those to determine bolt and nut sizes and coarse or fine threads. I would need both the SAE for the vette and the metric for my pickup. Thanks.
Race Director
Joined: Apr 2011
Posts: 11,183
Likes: 3,335
From: North of Toronto - Ontario
As he says, chasing with a tap can be dangerous, takes nothing to all of a sudden be cutting and creating a fresh newly stripped hole. In a pinch you can knock the cutting edge down with a stone to prevent that.
Dealing with old cars it's well worth buying even a basic set of thread chasers
Summit SUM 900203 for fine and 900200 for coarse, will cover 99% of every thread on an old car, for outside threads you can usually get by with a set of thread files for the fine and coarse pitches or splurge and buy a complete set which usually has fine coarse and metric, male and female and a file or two, check amazon
Well worth the investment
M
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
As he says, chasing with a tap can be dangerous, takes nothing to all of a sudden be cutting and creating a fresh newly stripped hole. In a pinch you can knock the cutting edge down with a stone to prevent that.
Dealing with old cars it's well worth buying even a basic set of thread chasers
Summit SUM 900203 for fine and 900200 for coarse, will cover 99% of every thread on an old car, for outside threads you can usually get by with a set of thread files for the fine and coarse pitches or splurge and buy a complete set which usually has fine coarse and metric, male and female and a file or two, check amazon
Well worth the investment
M
Dealing with old cars it's well worth buying even a basic set of thread chasers
Summit SUM 900203 for fine and 900200 for coarse, will cover 99% of every thread on an old car, for outside threads you can usually get by with a set of thread files for the fine and coarse pitches or splurge and buy a complete set which usually has fine coarse and metric, male and female and a file or two, check amazon
Well worth the investment
M
Even if you are careful and perfect using a tap to chase threads they still remove material. It's just the nature of their design.
I teach a workmanship class for my technicians at work and have a lot of experience with the proper use of tools of all kinds. I started these classes because I'd have to fix their F-up's and some of our components are very expensive and many times it was because they used taps instead of thread chasers.
Also, removing just a little bit of material in threads or bolts will change the torque properties of the fastener. People can do whatever they want but if I'm not creating new threads I use my thread chasers.
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Thread Starter
8th Gear
Joined: May 2018
Posts: 8
Likes: 1
From: Austin, TX.
The PO had apparently cross threaded one of the shaft ends. I was hopeful that chasing the threads might save me the expense of purchasing a new shaft. I had planned on using it on the other three, but after reading this, should probably leave well enough alone. The good news is that since the PO had been doing this before the ball joints were bolted in. Mine is a '68. Thanks gentlemen.
Team Owner
Joined: Jun 2001
Posts: 23,375
Likes: 1,067
From: Virginia USA
The PO had apparently cross threaded one of the shaft ends. I was hopeful that chasing the threads might save me the expense of purchasing a new shaft. I had planned on using it on the other three, but after reading this, should probably leave well enough alone. The good news is that since the PO had been doing this before the ball joints were bolted in. Mine is a '68. Thanks gentlemen.
Thread Starter
8th Gear
Joined: May 2018
Posts: 8
Likes: 1
From: Austin, TX.
Thanks to all. I guess I will be going on-line to purchase an upper control arm shaft. Hopefully, with all the email ads I have received from various vette vendors, I can find some deal for Christmas.