Thread Info

[frbush]

I have a small indexer that is similar to a Kalamazoo A-1 or Yuasa 550-009. My problem is that I can't find cap screws to mount a 4" chuck. I have tried every SAE size that I know of. That leaves the metric sizes. I went to the largest metric supplier in Dallas and they couldn't fit it. The threads appear to be larger than a 4mm but smaller than a 5mm. The pitch looks coarser than the normal .7 pitch. I have been told that there is a 4.5mm x .75. Anyone have any suggestions?
Desperate in Dallas

 

[Pazuzu71]

Can it be drilled out, and re-tapped to a 'normal' size?
That's what I'd try.

 

[CCWKen]

Yep, 4.5mm x .75 is a valid metric, BUT... not very popular. I checked McMaster-Carr and they don't carry it. If MC doesn't carry it, I don't know who would. They are normally my savior for the unique and hard to find stuff.
I'd go with Pazuzu's sugestion. You could drill and tap to 10-24 or 10-32. That's only .010 over your 4.5mm.

Ken

 

[frbush]

Yes I immediately thought about drilling and retapping to a standard size but this baby has been hardened almost as hard as my head.
Maybe we have some friends from Europe that can give a good supplier.

 

[WJHartson]

There is another posibility and that is BA thread. It has a 55 degree thread. Where was you indexer made? If in England it could be the BA thread.

 

[GN_Mike]

http://www.legereindustrial.com/web/catalogue/sect1_p6-10.pdf

Take a look on Pg. 3 on the left hand column, Dormer sells taps.

I also found this site. http://www.tapdie.com/index.html

..Mike

 

[Dr. Rob]

Dudes, I live in Europe, and work with nothing but Metric. There are normal metric things, and odd metric things. M4.5 x .75 is so out-of-this-world oddball that I can tell you right now, that trying to find it in the civilized world is an exercise in futility.

I have, on the other hand encountered a screw of similar description, which I immediately regarded as being an oddball american one. I do know a guy who would have the proper definition of it, though. I'll ask later.

 

[Alan in Oz]

Frbush,
I have looked at my chart and 4.5 by .75 is listed as metric course, tapping drill 3.8 mm. Shall contact a supplier tomorrow to see if a die is available & at what cost, but feel its rare as Dr Rob mentioned. It also seems small to be holding a chuck on.

 

[frbush]

Solved the problem. Still don't know what the actual thread is but I found that I could chuck up a 10-24 and shave about .015 off the crest and it fits just perfect. Thanks for all of the suggestions. Gone to look for a new problem.

 

[Lambert]

This might be of some help for the next time : get yourself a couple of sets of `thread gages`

Dunno about their english name ; they are made of small steel plates with a standard thread profile (Metric , or UN , or Whitworth or ....).
It looks like a `thickness feeler gage` , a set of these small plates which are packed together , with their pitch marked on them.
This of course gives you a `threadform` with the correct depth , shape and pitch wich you can fit on a bolt to see which one fits `perfectly`.

Lambert

 

[Alan]

Frbush,
Just for your info as you have already solved the problem, supplier here in Aust says split die 4.5 by .75 mm available off the shelf at equiv of US$38 (A$57)

 

[Peter S]

Here is a chart that compares English/USA/Metric threads.

http://easyweb.easynet.co.uk/~chrish/

Look for "Engineering/Workshop data", then "Thread substitution chart"

 

[WJHartson]

Peter S.

Good web site. I would say the correct screws are 3/16 - 24.

Joe

 

[Peter S]

Joe,
If you liked that one....this one, by Stephen Wellcome, has 50 pages and sorts threads by pitch and diameter.

http://users.rcn.com/sas.ma.ultranet/sizes.pdf

And this one is good too, by Ian Wright, 8 pages, (see also his interesting stuff on making files)

http://www.watchman.dsl.pipex.com/thread.html


[This message has been edited by Peter S (edited 07-02-2003).]

[This message has been edited by Peter S (edited 07-02-2003).]

 

[CERT. (A) MACHINIST]

pull out your thread gage and make one.