How can I get a bolt to spin freely into the threading?

Reply

  #1  
Old 11-08-19, 12:06 PM
Member
Thread Starter
Join Date: Sep 2003
Location: Arlington, VA
Posts: 860
Received 0 Votes on 0 Posts
How can I get a bolt to spin freely into the threading?

You know how sometimes you'll have a bolt that you crack loose and then it spins freely out of the threading (this is what I want)
and other times you crack a bolt loose but effort is still required to turn it out of the threading? (this is what I have)

My case, specifically, is I'm adjusting the clutch pushrod on a Baker motorcycle transmission.
The instruction, at the transmission end, is to tighten the pushrod until you feel the slightest tension and then back it out a 1/4 turn. (and then tighten the locking nut, put the cover back on etc etc)

Starting from completely out, my pushrod will only spin freely one or two turns max before it encounters a good amount of tension but that tension is not the clutch cable providing the tension (which is the idea here), instead, that tension is from the threading itself being sticky so it's hard to tell when the tension from the clutch cable is.

Any ideas on how to get the threading to be free spinning so that I can tell when the clutch cable is providing tension?
 
Sponsored Links
  #2  
Old 11-08-19, 01:32 PM
Norm201's Avatar
Member
Join Date: Sep 2013
Location: United States
Posts: 7,606
Received 91 Votes on 83 Posts
Could be several reasons. Is the threaded rod perfectly clean? No grime or dirt. Has it ever had any thread lock applied to it? Has the nut or rod have any nicks in it? Often the first few threads will be worn away enough to allow a damaged thread to spin freely. Is the rod perfectly straight? That is perhaps the biggest problem. I would try another nut.
 
  #3  
Old 11-08-19, 01:38 PM
Member
Thread Starter
Join Date: Sep 2003
Location: Arlington, VA
Posts: 860
Received 0 Votes on 0 Posts
It's the rod itself that screws into the housing.
Rod looks like it's in good condition, not sure about thread locker.
I'll clean grime and dirt off it.

Any recommendations on how best to get rid of grime and dirt? Metal polish?
 
  #4  
Old 11-08-19, 01:56 PM
pugsl's Avatar
Forum Topic Moderator
Join Date: Mar 2008
Location: Raleigh, NC
Posts: 8,518
Received 25 Votes on 24 Posts
Spray brake clean works for me. If Threads are clogged with rust than some PB Blaster works.
 
Norm201 voted this post useful.
  #5  
Old 11-08-19, 02:42 PM
Member
Join Date: Nov 2012
Location: USA
Posts: 1,303
Received 36 Votes on 29 Posts
First
Double check to make sure the bolt is meant to go there.
Do the threads match- e.g. fine-thread vs coarse thread? Thread pitch?
Can You Explain Some Basic Screw and Thread Terms? - MW Industries ASM

Try screwing a chopstick or soda straw into the hole, the markings should let you tell if the threads are coarse/fine.

Now, a small battery terminal cleaner would be my first option to clean out the hole.
 
  #6  
Old 11-08-19, 03:31 PM
Member
Join Date: Feb 2006
Location: USA
Posts: 6,573
Received 4 Votes on 4 Posts
Re-tap the threads on the rod with a tap and dye.
 
  #7  
Old 11-09-19, 06:01 AM
Group Moderator
Join Date: Mar 2003
Location: NC, USA
Posts: 21,240
Received 266 Votes on 241 Posts
You can run the part in and out, cleaning the threads off each time you have it out. Keep doing it as long as it's still tight and your'e wiping stuff off the threads.
 
  #8  
Old 11-09-19, 07:50 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,119
Received 2 Votes on 2 Posts
I've used a brass gun barrel cleaning brush chucked in a drill to clean out the threads on many things. Just get one slightly larger than the bolt threads. I regular brass wire bush and some solvent should clean off the bolt threads just fine. Make sure you don't have a burr on the bolt threads. Try running a new regular bolt in the hole in the trans.
 
  #9  
Old 11-09-19, 08:15 PM
XSleeper's Avatar
Group Moderator
Join Date: Dec 2004
Location: USA
Posts: 23,512
Received 249 Votes on 228 Posts
If you use a wire wheel on a bench grinder to clean the threads, make sure you have gloves on and keep a tight hold on it, or *zing*! (Pushrod gets launched across garage)
 
  #10  
Old 11-10-19, 05:49 AM
Marq1's Avatar
Member
Join Date: Sep 2016
Location: USA MI
Posts: 4,608
Received 125 Votes on 116 Posts
Re-tap the threads on the rod with a tap and dye
You can run the part in and out, cleaning the threads off each time you have it out. Keep doing it as long as it's still tight and your'e wiping stuff off the threads
The only way your going to alter the thread is to run a die on the thread.

When the part was made the die could have been worn thus not properly shaped threads.

Also the thread Tolerance will effect how it fits along with if the part was plated.

When I work on my car projects pretty much every nut and bolt gets a quick chase and a coating of oil, sure makes assembly a lot easier!
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: