Technical Machinists, I've got a measurement question - new studs in 40 Ford hubs

This is not directed at ANY particular person but "intending" to do something and the end result many times aren't the same thing.
The thing with the .010-.015 range is that is a reasonable number to achieve the intended result based on what is readily available in the average guys' tool inventory, a well stocked machinists cabinet notwithstanding.
Considering not having plus/minus or adjustable reamers available not to mention the cost usually leaves pretty much one other option to the average guy and that is a 1/2" drill index in 1/64" increments.
Granted, most lug stud serrations will be over 1/2" but most big box stores or well stocked local hardware stores will have drill bits in 1/64 (.015) increments.

 

Denny, my experience is that you can find 1/2" shank bits locally larger than 1/2" in 1/16" increments fairly easily, 1/32" much less so, and 1/64" rarely. I'll admit it's been awhile since I bought one, maybe it's gotten better, but it took me numerous phone calls and a 50 mile drive to get mine. The cost of a 'set' from 33/64th through 1" will take your breath away... Probably just as cheap or cheaper to buy a decent import set of adjustable reamers.

 

Steve
You are probably right about the 1/64" increment deal, I guess I was spoiled at the time as I ran the toolroom at work but even my drill sets at home are in 1/64" increments.
I did my hubs on a Saturday with what I had but I easily could have brought home a reamer, I just forgot it.
Like I said prior, the bit needs to be sharpened equally to expect to hold tolerance, at least when drilling a new hole from scratch.

 

This subject is about to get worn out. There have been a lot of good suggestions, but here's my opinion anyway.

If I was doing the job I'd measure the outside of the serrations and the depth, since some serrations are much coarser/deeper than others. Then bore the hole to have an interference fit about 1/4 the depth of the serrations. As an example, if the depth of the serration is .020 I would make the hole .005 smaller, or actually a total of .010 to include the serration 180 degrees across from it. That would deform the top .005 of the peak of the serrations all the way around the hole.

Since the object of the serrations is only to keep the stud from spinning in the hole when you tighten or loosen the lug nut it really doesn't need to be very tight in the hole, provided you keep the threads lubed and in good condition. The less interference, the easier it will be on the hub.

Pulling it in with a nut will assure that the stud is square to the bore and not being pushed sideways by a big assed press.
Have fun.

 

I would work my way up drill size to 19/32 (.5938) and then plunge with a endmill some where in the .610-.612 size with a re sharpened undersized endmill. That way you know it's round and size. I'd also put a good chamfer on the backside of the axle flange that the stud goes in from, that should help get it started easier.

 

What size is your existing hole? I see studs with .535 .560 .563 .589 .594 and .615 knurl dia. Among others. I still think making the stud fit the hole is smarter than making the hole fit the stud.

 

That's totally logical to you and I or anybody that does their own work, but throw some air gun lunatic into the mix out on the interstate and you're really up a creek.

 

Guess I'm just assuming, but figured he may be going from a 7/16" to 1/2" stud for strength.

 

I thought he may be going to long studs to use aluminum wheels and meet association safety rules. That's why I put studs in Ford hubs. And my early Ford came with 1/2-20 studs.

 

I don't know why. My studs had a flat that rested against a shoulder on the Ford hub to prevent rotation. That car is still running around 40 years after I put those long, turned down studs in it. And I have not heard any complaints yet. No interstate time though.

 

Any pilot hole (once it is determined..) will be a fractional drill size. Probably going 1/64" under what the stud measures will be fine.

OR... make me a liar...
https://help.summitracing.com/app/answers/detail/a_id/4639/~/what-size-drill-bit-do-i-need-to-install-new-wheel-studs?

Drill size seems to be .005 to .007 less than the OD of the knurl. This is why I go to the Machinery Handbook when I have to do something like this.

 

From Jegs: Even a lighter press-fit. Going to need some odd sized reamers to get the right size for these.
https://www.jegs.com/p/Moroso/Moroso-Wheel-Studs/748727/10002/-1

 

Going from a smooth shank original Ford 1/2" stud that was retained by swedging and locked from rotating by a square edge that sat against a matching edge on the hub casting.

For use with their replacement cast drums, Boling Bros recommends a 610-234 stud in a hole that is reamed to .600". The 610-234 stud has a .621" knurl diameter as compared to the .623" knurl diameter on the studs alchemy is inquiring about. Should get you in the ballpark.

 

Use a micrometer (calibrated) guys, not a plastic caliper from HF.

 

Here's what we ended up doing. Gary, my personal machinist used the .012" press fit number and drilled all the holes to 39/64". He first located every hole with the original existing size bit, then clamped the hub to his mill table. Then switched the bit for the 39/64".

After drilling all these I had asked him to face the flat sided rib off the back of the hub a bit so I could use my new round headed studs. He asked if it wouldn't be easier to just grind a flat off the head of the new stud. I said okay, so I did it. Now they are locked in there with serrations as well as a flat side. They will never turn.

He also, before we pressed any studs in, re-cut the mounting face of the hub because these old dogs were rather wavy. Now I have smooth new hubs with the strength of real Ford metal.

The hubs will have new MT Products slip on drums from Boling Brothers. They fit great.

And don't pay any nevermind to the smaller BC on the hub, those were there when I bought these used and abused hubs at the Springfield swap meet last August.

 

Mine.

https://www.jalopyjournal.com/forum/threads/ford-lug-stud-new-drums.278605/

 

It's really difficult to slightly enlarge a hole with a drill, it catches, pulls in and will often make a somewhat irregular and oversize hole.
A reamer is the way to go, even a cheapy from ebay will last quite a few holes.

 

Also a good chamfer will help guide a drill bit. I almost always strap anything I need to drill onto my Bridgeport table or hold it in the vise.

 

FWIW, the Dorman catalog has the recommended hole size for the knurl size for all their wheel studs.
It’s in the back pages, with pictures and dimensions of the stud.
Old school, so your everyday AZ, Advanced, etc. may be of no help.