CR4 - The Engineer's Place for News and Discussion ®


Previous in Forum: Graduate Mech. Coordinator - Looking for Advice   Next in Forum: Fuel Oil Dyke Area and Transmission Line
Close
Close
Close
30 comments
Power-User
Engineering Fields - Biomedical Engineering - New Member Fans of Old Computers - TRS-80 - New Member

Join Date: Aug 2009
Location: Omaha, Nebraska (fly-over country USA)
Posts: 284
Good Answers: 7

Machine Screw Improvement (?)

10/04/2016 12:58 AM

Seems lately that a lot of parts I need to replace/install with a standard machine screw need to be connected on 'blind' mountings. That is, you have to hold the part in place and hope/pray/swear you get the screw lined up with the threads you cannot see due to the angle or small space you are working in.

Not sure if this would cause trouble with carving the threads, but could a screw have a point on the end to help place it into it's destination? The then the threads would take hold and secure the assembly in place.

Of course - probably higher cost manufacturing the modest screw??........

__________________
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka" but rather "Hmmmmm...that's funny" - Isaac Asimov 1920-1992
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru

Join Date: Oct 2008
Posts: 39415
Good Answers: 1559
#1

Re: Machine Screw Improvement (?)

10/04/2016 1:27 AM

This is where "feel" comes into play.

If you cross thread a bolt or screw, it's more than likely your fault.

Generally, if you feel resistance to rotation after 1/2 turn, STOP.

The lead thread will usually engage, or not, within the first turn.

Alignment is important too but just don't force it. Back up and start over.

An unthreaded lead might help.

Register to Reply
Power-User
Engineering Fields - Biomedical Engineering - New Member Fans of Old Computers - TRS-80 - New Member

Join Date: Aug 2009
Location: Omaha, Nebraska (fly-over country USA)
Posts: 284
Good Answers: 7
#19
In reply to #1

Re: Machine Screw Improvement (?)

10/05/2016 7:52 PM

Cross threading is not my issue...

Sometimes it is even getting the screw to find the threads!

__________________
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka" but rather "Hmmmmm...that's funny" - Isaac Asimov 1920-1992
Register to Reply
2
Guru

Join Date: Apr 2011
Posts: 6409
Good Answers: 236
#2

Re: Machine Screw Improvement (?)

10/04/2016 6:36 AM

One approach that can help avoid cross threading is when positioning the machine screw, initially turn to loosen (so counter clock wise for standard threads) until you feel the two end of thread pass one another and click in one thread pitch. Beginning to tighten from that point makes it easier to thread correctly and to detect if something is not right.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply Good Answer (Score 2)
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3299
Good Answers: 81
#7
In reply to #2

Re: Machine Screw Improvement (?)

10/05/2016 4:03 AM

That also works well for large diameter fine pitch threads where it is very easy to cross thread the parts.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
2
Guru
Australia - Member - New Member

Join Date: Feb 2008
Location: Australia
Posts: 1730
Good Answers: 201
#3

Re: Machine Screw Improvement (?)

10/04/2016 7:55 AM

There are multiple threaded fasteners available that have no thread (just root diameter shaft) for the first 5 turns or so. These are specifically handy in automatic assembly to assure part alignment.

They are also especially handy where the fastener is fixed in pace and you have to fit a nut in those tight spaces. Automotive fixturing for rear combinationlamps and such.

__________________
Just an Engineer from the land down under.
Register to Reply Good Answer (Score 2)
Power-User
Engineering Fields - Biomedical Engineering - New Member Fans of Old Computers - TRS-80 - New Member

Join Date: Aug 2009
Location: Omaha, Nebraska (fly-over country USA)
Posts: 284
Good Answers: 7
#20
In reply to #3

Re: Machine Screw Improvement (?)

10/05/2016 7:53 PM

This is what I'm thinking of!!

Any idea of a source? I'm not even sure what to call it...

__________________
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka" but rather "Hmmmmm...that's funny" - Isaac Asimov 1920-1992
Register to Reply
Guru
Australia - Member - New Member

Join Date: Feb 2008
Location: Australia
Posts: 1730
Good Answers: 201
#23
In reply to #20

Re: Machine Screw Improvement (?)

10/06/2016 6:57 AM

We were buying these by the tonne as specialty fasteners. The other end was a HiLo thread for plastic with a shoulder midway.

One suplier was "Auto screw company",but that was over 8 years back and in Aus.

__________________
Just an Engineer from the land down under.
Register to Reply
Guru
Canada - Member - New Member

Join Date: Jul 2013
Location: Canada but south of 49
Posts: 724
Good Answers: 17
#26
In reply to #20

Re: Machine Screw Improvement (?)

10/11/2016 9:30 AM

Automotive uses a lot of these called "SEMS" screws. There are also other specials available.

You can goggle "spae-naur" and see the catalogue, and I also know that Fastenal can get them.

__________________
Never stop learning
Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3299
Good Answers: 81
#27
In reply to #26

Re: Machine Screw Improvement (?)

10/11/2016 9:34 AM

i thought SEMS were screws with pre-installed washers?

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Guru
Canada - Member - New Member

Join Date: Jul 2013
Location: Canada but south of 49
Posts: 724
Good Answers: 17
#29
In reply to #27

Re: Machine Screw Improvement (?)

10/11/2016 10:36 AM

A true SEMS, yes. But there are some variations available.

__________________
Never stop learning
Register to Reply
4
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 18688
Good Answers: 1089
#4

Re: Machine Screw Improvement (?)

10/04/2016 10:44 AM

Well you could design a mechanism to work....like these MAThread screws....

...or Taptite screws....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply Good Answer (Score 4)
Power-User
Engineering Fields - Biomedical Engineering - New Member Fans of Old Computers - TRS-80 - New Member

Join Date: Aug 2009
Location: Omaha, Nebraska (fly-over country USA)
Posts: 284
Good Answers: 7
#21
In reply to #4

Re: Machine Screw Improvement (?)

10/05/2016 7:59 PM

Outstanding!! Just what I'm thinking...thx

__________________
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka" but rather "Hmmmmm...that's funny" - Isaac Asimov 1920-1992
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18602
Good Answers: 327
#5

Re: Machine Screw Improvement (?)

10/04/2016 11:08 AM

truth is not a compromise has great advice,

Also on my car it has a number of these types of mounts that it was inaccessible, or very hard. Where if you use your hand there's no space for much else even tightening. The last I worked on my car, when I was reassembling it, I had to walk away.

Then I purchase a set of these forceps, (or Locking Clamp Pliers as HF may call them) @ HF.

I used them to hold the fasteners in place, using them I was able to see what I was doing not only with the fastener but with the wrench also and in less than a 5 minutes using these, all screws were caught and tightened.

__________________
phoenix911
Register to Reply Score 1 for Good Answer
Guru

Join Date: May 2006
Location: Placerville, CA (38° 45N, 120° 47'W)
Posts: 4485
Good Answers: 160
#6
In reply to #5

Re: Machine Screw Improvement (?)

10/05/2016 1:14 AM

Are those different from Hemostats? I have and use two or three different sizes.

__________________
Teaching is a great experience, but there is no better teacher than experience.
Register to Reply
Power-User

Join Date: Jan 2015
Posts: 108
#9
In reply to #6

Re: Machine Screw Improvement (?)

10/05/2016 7:32 AM

I've used various types of hemostats for years. When I was young and broke I would ask my doctor for old sets. The first time I got a strange look and had to explain 'why' I wanted them. I guess there are uses other than surgery and holding small parts and getting in difficult places.

Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18602
Good Answers: 327
#10
In reply to #6

Re: Machine Screw Improvement (?)

10/05/2016 7:43 AM

I had to look at the difference between forceps and hemostats. But are similar. But what I love about them, is the locking ratchet.

With the difference sizes of forceps/hemostats, you can lock onto a little screw squeeze it , I thought at first that the screw would shoot out and loose it. But it hung onto it beautifully. You could never hold it with your hands to place correctly and with this you can place it.

When I was at Harbor Freight, I purchase all the types and kinds they had.

I don't recall the sizes 3", 4" 8", 12 or 15"" and with the Straight Jaws, 45 degree jaws.

I highly recommend it for your tool box, but you already know that.

__________________
phoenix911
Register to Reply
Guru
Engineering Fields - Instrumentation Engineering - EE from the the Wilds of Pa.

Join Date: Feb 2006
Location: middle of nowhere, Pennsylvania
Posts: 2488
Good Answers: 58
#11
In reply to #5

Re: Machine Screw Improvement (?)

10/05/2016 8:35 AM

Yeah - I use forceps at home for my bicycle work. I originally bought them for electronic parts placement in the old discrete component / breadboard days. Just don't take them to work, unless you are in Colorado - co-workers recognize them as a tool used by potheads.

__________________
Remember when reading my post: (-1)^½ m (2)^½
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18602
Good Answers: 327
#12
In reply to #11

Re: Machine Screw Improvement (?)

10/05/2016 8:47 AM

Electronic coomponents, yes.

As far as Colorado...

Wow, my first fist to Colorado was to Colorado Springs in 99. Beautiful place.

Went to the Garden of the Gods and came out at Manitou Springs. Nice little tourisy town with gift shops.

I took my Girlfriend there back in 2010 when her son was getting deployed to Iraq from Fort Collins. Didn't have time for it but we returned back there to visit some friends in 2014.

Of course I said to my girlfriend what a great little place this Manitou Springs was, that she would love it. got there and WOW,... head shops, unemployed musicians looking for an audience, acne scared 20 something's stumbling around looking for something that's not there. ya, I hear ya...

__________________
phoenix911
Register to Reply Score 1 for Off Topic
Guru
Engineering Fields - Instrumentation Engineering - EE from the the Wilds of Pa.

Join Date: Feb 2006
Location: middle of nowhere, Pennsylvania
Posts: 2488
Good Answers: 58
#13
In reply to #12

Re: Machine Screw Improvement (?)

10/05/2016 10:32 AM

Remember Floyd Landis, the 2006 Tour de France winner, who was stripped of the title for doping? That's where he has landed. Check out Floyd's of Leadville - he has gone from being banned from cycling for illegally doping, to selling dope legally.

__________________
Remember when reading my post: (-1)^½ m (2)^½
Register to Reply Off Topic (Score 6)
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18602
Good Answers: 327
#14
In reply to #13

Re: Machine Screw Improvement (?)

10/05/2016 10:36 AM

ha, by climbing the ladder doesn't always mean going up.

__________________
phoenix911
Register to Reply Off Topic (Score 5)
Guru

Join Date: Apr 2011
Posts: 6409
Good Answers: 236
#17
In reply to #14

Re: Machine Screw Improvement (?)

10/05/2016 2:20 PM

....Leadville IS the highest (perhaps in more ways than one) incorporated city in the US... so there W's at least some aspect of going up.

__________________
Eternal vigilance is the price of knowledge. - George Santayana
Register to Reply Off Topic (Score 6)
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3299
Good Answers: 81
#8

Re: Machine Screw Improvement (?)

10/05/2016 4:10 AM

Not much help if you are rebuilding old equipment but, if you were designing from new, you could take the other approach & use a standard screw but counter drill the first few threads in the tapped hole to locate it.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply Score 1 for Good Answer
Guru

Join Date: May 2016
Posts: 746
Good Answers: 38
#15

Re: Machine Screw Improvement (?)

10/05/2016 10:54 AM

I was involved in final assembly of landscaping equipment and the best results we had were with the piloted screws that Solar showed in his post. Additionally, we did counterdrill threaded holes for about 3 threads depth to guide on the OD of the screw threads. The pilot on the screw was just slightly less than the tap drill of the threaded hole.

In assembly, you got one click as the pilot dropped in, a second click when the od of the screw dropped into the counterdrill and then you were 99.9% lined up and ready to tighten. We were using magnetic tip JIS cross head drivers in torque controlled screw guns. We had final assembly of string trimmers down to about 120 seconds per trimmer and as low as 90 seconds on a good day. That included installation of the engine, connection of the throttle and ignition, installation of a handle and packaging the finished unit, a total of 15 screws in 3 sizes.

Register to Reply
Guru

Join Date: Jun 2008
Posts: 816
Good Answers: 33
#16

Re: Machine Screw Improvement (?)

10/05/2016 12:36 PM

Try Lee Valley--They have a finger, glove type mechanism, that contains a small rare-earth magnet that holds the nut in place, on the backside, out of visual range, while you "feel" the bolt or machine screws into it from the front. Works great.

Register to Reply
Guru

Join Date: May 2006
Location: Placerville, CA (38° 45N, 120° 47'W)
Posts: 4485
Good Answers: 160
#22
In reply to #16

Re: Machine Screw Improvement (?)

10/05/2016 8:45 PM

That'll only work for magnetic nuts. I use a lot of brass and Stainless, so the Hemostat commonly does the job.

__________________
Teaching is a great experience, but there is no better teacher than experience.
Register to Reply
Guru
United Kingdom - Member - Old New Member

Join Date: Jul 2005
Location: South east U.K.
Posts: 3299
Good Answers: 81
#25
In reply to #22

Re: Machine Screw Improvement (?)

10/11/2016 5:18 AM

These work for any material, I've had a set for years for those tight situations.

__________________
I didn't have a really important life, but at least it's been funny (Lemmy Kilminster 1945-2015)
Register to Reply
Guru

Join Date: May 2006
Location: Placerville, CA (38° 45N, 120° 47'W)
Posts: 4485
Good Answers: 160
#28
In reply to #25

Re: Machine Screw Improvement (?)

10/11/2016 10:16 AM

Interesting! I hadn't seen those. Are they available in the USA?

__________________
Teaching is a great experience, but there is no better teacher than experience.
Register to Reply
Guru

Join Date: Jul 2006
Location: CA (Central Arkansas, USA)
Posts: 544
Good Answers: 9
#18

Re: Machine Screw Improvement (?)

10/05/2016 3:37 PM

That's how it's done on race cars.

__________________
If it's too good to be true, it probably isn't
Register to Reply
Active Contributor

Join Date: Aug 2016
Location: Pune
Posts: 13
#24

Re: Machine Screw Improvement (?)

10/11/2016 5:04 AM

Sizes:

Jolts are measured by, string and length in a specific order. Much of the time, distance across and length are recorded in inches, and string in strings per crawl. Along these lines a one-fourth-crawl width dash, with 20 strings for each creep, two creeps in length, would be recorded as a one-fourth creep x 20 x 2 crawl or quarter/20 x 2 creep.

Once in a while, strings are recorded as UNF (fine) or UNC (coarse) rather than per creep. Only a little variety to keep things intriguing.

Why have distinctive sorts of strings? Fine strings make a more grounded jolt that can be torqued up more tightly than a dart with coarse strings. They are additionally better on littler jolts. Then again, coarse strings are harder. They'll hold better in high-wear circumstances, or when you may need to evacuate or supplant the jolt as often as possible. They likewise oppose cross threading superior to anything fine strings.

On the off chance that you need to purchase a fastener to fit a particular nut, bring the nut with you to the store and ensure you can string it onto the screw you purchase. String it the distance on. Infrequently a nut will go on a turn or two regardless of the fact that it doesn't coordinate the string of the fastener.

__________________
rshirsagar5
Register to Reply
Member

Join Date: Sep 2016
Posts: 5
#30

Re: Machine Screw Improvement (?)

10/14/2016 6:04 AM

I have some information to share out about screw

About size / design / function

Our can read over here---->http://crbtech.in/CAD-CAM-Training/designsizefunction-screw-conveyor

thank you

Register to Reply Score 1 for Off Topic
Register to Reply 30 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be Good Answers:

These comments received enough positive ratings to make them "good answers".

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

C-Mac (1); Circuit Breaker (1); dkwarner (3); Jpfalt (1); Just an Engineer (2); Kevin LaPaire (2); lyn (1); Nigh (4); phoenix911 (4); Phys (2); rshirsagar5 (1); Sanikapatel (1); Sid_Sidow (3); SolarEagle (1); Torqued (1); truth is not a compromise (2)

Previous in Forum: Graduate Mech. Coordinator - Looking for Advice   Next in Forum: Fuel Oil Dyke Area and Transmission Line

Advertisement