AC setscrew taper?
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=15843
Printed Date: 05 Feb 2025 at 1:42am
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Topic: AC setscrew taper?
Posted By: Steve M C/IL
Subject: AC setscrew taper?
Date Posted: 29 Jul 2010 at 9:25am
| Anyone ever figured out the taper in degrees on the setscrews used all over the old AC's(WD45)? My crude method comes out to 21 degrees.Anyone know for sure? |
Replies:
Posted By: CTuckerNWIL
Date Posted: 29 Jul 2010 at 12:44pm
|
Anyone with access to an optical comparator out there?
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Steve M C/IL
Date Posted: 29 Jul 2010 at 1:50pm
| Charlie,I figured if anyone had this down it was you!My method used 2 shear cut 5/8 strips of 18Ga sheet metal pinched on the end with vise grip to form a vee then adjusting angle untill the tapered point of setscrew "fit" the angle formed.Kinda tricky trying to align screw with edges of strips not in the same plane.Lastly,used a protractor set to the vee point and reading the angle.Crude but I believe it's correct @ 21 deg. |
Posted By: bigfish_Oh
Date Posted: 29 Jul 2010 at 4:39pm
|
I'm a foot away from one 5 days a week(at this minute), which screw, I am sure a have a loose one or can take one off.
Larry ------------- 1941 WC sat for 29 years,started & dynoed 27 h.p. 1957 WD45 Grandpa bought new,factory p.s.,added wfe 1951 WD, factory p.s. 1960 D14 HnMk IV BkHoe 4 sale 2014 HD Tri Glide 2009 GMC CC SLT Dually |
Posted By: Rick of HopeIN
Date Posted: 29 Jul 2010 at 5:07pm
|
where are they used? I had never heard of that
------------- 1951 B, 1937 WC, 1957 D14, -- Thanks and God Bless |
Posted By: wfmurray
Date Posted: 29 Jul 2010 at 5:16pm
| Never heard of set screw tapers but could be. Some greese fittings and pipe thread are all 3/4in per ft. AC use some pipe thread on hyd. |
Posted By: Brian G. NY
Date Posted: 29 Jul 2010 at 5:58pm
| A-C sure did like those taper point set screws - they show up in the least expected places. LOL |
Posted By: CTuckerNWIL
Date Posted: 29 Jul 2010 at 9:08pm
|
They were used to hold the starter in, the belt pulley has one and the front crankshaft pulley has one. What have I missed?
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Brian G. NY
Date Posted: 29 Jul 2010 at 9:12pm
| The front spindle on the NFE; and i'm still thinkin'! |
Posted By: Gerald J.
Date Posted: 29 Jul 2010 at 9:22pm
Like this one? From McMaster-Carr? Gerald J. |
Posted By: CTuckerNWIL
Date Posted: 29 Jul 2010 at 9:30pm
|
90 degrees? That would be too easy Gerald. LOL ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: Tracy Martin TN
Date Posted: 29 Jul 2010 at 9:42pm
| Steering arms on spindles,brake pedals on G,bearings lock on G axle,hand clutch lever shaft on several to name few.I have several made to make the reproduction brake pedal shafts for G and WD. HTH Tracy Martin |
Posted By: Steve M C/IL
Date Posted: 29 Jul 2010 at 11:18pm
|
On my 45 they're on steering arms(wide front),crank pulley,starter,belt pulley housing and clutch/brake pedal shafts.My crank pulley ran loose a long time and reshaped the allen head setscrew taper(2 belt pulley).Not available anymore! Thought I'd have the machine shop refinish it but need to know the degree taper. Bigfish,the one from the steering arm appears to be the same taper.My guess is they all are.
Gerald; you're kidding,right?Keyword...TAPER.It's 5/8 11 NC with 5/16 Allen head x 1 1/2 long.Mccarr has nothing close.
|
Posted By: Gerald J.
Date Posted: 30 Jul 2010 at 1:36am
|
Unless the mating parts have a tapered hole to match, the taper angle is there to force alignment of a straight hole with the straight threads, and is not terribly critical. Changes in the slope change the side force multiplier from the thread motion. Much like a Gib key, but in this case round and perpendicular. Since set screws tend to be very hard, a machine shop would probably need to start with a long screw and set up a tool post grinder to make the shape. They'd lock two nuts near the middle of the screw to drive it, with a loose one near the head to center it in a 3 or 6 jaw chuck and grind away. Several minutes per screw. Sounds expensive. If you have one in good shape, they can mount it the same way with a dial indicator in the tool post and swing the feed until its parallel to the existing screw and don't need to know the measured angle. Its probably too steep to use the taper attachment and using the dial indicator on a good part is the best way to set it. The angle they'd start with is the angle from the axis, not the included angle which is what Steve M tried to measure. Grabbing the screw threads directly isn't great for the threads or the chuck. A threaded collet would be used for production work. Rather than the complication of two strips of metal, why not two THIN feeler gauges, or cut a slot in one strip of metal, then adjust the angle until it fits the taper. Either takes out most of the uncertainty. Otherwise measure the diameter at two points having carefully marked them and then measure the distance between them, and put a scientific calculator to work to get the angle, or just give the machine shop the three measurements. E.g. .127" from the end the taper diameter is .364" and .637" from the end the diameter is .567". That's 21 degrees included angle, or 11.5 degrees to turn the tool post feed. formula. tool post angle = inverse sin ((bigradius - smallradius) / spacing) where the radii are half the measured diameter. The included angle is twice the tool post angle. Gerald J. |
Posted By: Jack(Ky)
Date Posted: 30 Jul 2010 at 4:48am
| Starter and power directer handle on D series. They worked really well. Anyone that knows geometry can figure it easy (not me). You need to know both diameters and the length between the two. Any tool and die guy can figure it out. The "Machinist Handbook" will have the formula.JP |
Posted By: CTuckerNWIL
Date Posted: 30 Jul 2010 at 7:14am
|
Gerald, I've turned a lot of hardened bolts and set screws in a lathe. The easiest way is a 5C collet. Chuck right on the OD. Carbide inserts are not effected by hardened bolts and I have never had a problem with the threads spinning in the collet. Steve, if the set screw was reshaped, the hole it goes into will be more effected than the setscrew. Unless you can redrill the hole to make it round, I don't think the angle on the screw would matter much. ------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |
Posted By: alan-nj
Date Posted: 30 Jul 2010 at 7:52am
| shift rails on wc shifter. |
Posted By: Steve M C/IL
Date Posted: 30 Jul 2010 at 9:41am
|
Charlie this cheap little fix has turned into full blown major O/H with line boring,decking block/head and a NEW crankshaft so I'm counting on a "good" hole in the crank. Gerald; AC tapered setscrews allways fit in a tapered matching hole. |
Posted By: CTuckerNWIL
Date Posted: 30 Jul 2010 at 11:39am
|
I guess your hole wouldn't be all washed out then. You could get some high spot bluing and fit the taper to a known good hole.
------------- http://www.ae-ta.com" rel="nofollow - http://www.ae-ta.com Lena 1935 WC12xxx, Willie 1951 CA6xx Dad bought new, 1954WD45 PS, 1960 D17 NF |