TheSamba.com :: View topic - Press-in lug studs and what size to ream the holes

Tue Apr 14, 2020 3:11 pm

Quoting myself,
Quote: There is another rant to spin off from that purchase, but that's NOT the fault of Dan's Performance Parts. Next post in this thread... Might be a separate rant thread.

I just bought some press-in studs and nuts for the back of my Baja. Those purchases leed to some troubles getting what I thought I was ordering. That's covered in another thread about what appeared to be dishonesty in marketing. Got it fixed now and am expecting more lug nuts from Appletree. Got some EMPI studs from Dan's Performance, and they got them to me quickly with no problems.

Now comes the problem.

I've installed such studs in VWs for over 40 years now. I have a fixture I made decades ago for that purpose for use with my hydraulic press. I put studs in the drums of my Hi Jumper you see in my avatar in the mid 1970s. Bought them direct from Sway-A-Way then. They were the only game in town for studs made specifically to fit VWs for many years. Installing Sway-A-Way studs has always required reaming the holes in the drum or adapter plate or rotor to 9/16" before pressing the studs in. SAWs are still the same.

Then around the late 80s/early 90s, BugPack started selling their versions. Similar, but not as nicely made as SAW. I've used theirs many times and never had any failures or problems, they're just not as nice. BugPack always required reaming the stud holes a little larger, to 37/64", or about .008" larger radius in the hole than for SAW studs. And for years, BugPack included a piece of paper in the vacuum packed card of studs that instructed the user to ream to that size.

Then a few years ago, EMPI bought up Bugpack, along with most of the other manufacturers and vendors of VW aftermarket items.

So a week or so ago, I decided to upgrade the rear adapters on my Baja from lug bolts (damned things oughta be outlawed!!!). So I ordered and received some new EMPI lug studs. Look nicer than Bugpack's. No indication on the package what size to ream the holes. That's NOT good!

Went to the EMPI online catalog that I have downloaded. Checked online and found the 2018 catalog I had is the current one. Checked out the item on page 337 (351 by pdf) and found:
Quote: 70-2850 Stud - Drum, M14-1.5 x 1.855" Long, Black. Set of 5
Yup...Same item.
Read the text:
Quote: Requires machining for press fit installation. A 9/16" drill bit should be used, may require reaming to 37/64".

OK. So I set up the drill press with a 9/16" drill bit, set the spindle speed to match 9/16 drill diameter cutting hardened steel. Then proceeded to ream out the holes.

Then I set up my hydraulic press. Because it lives out doors, I always remove the cylinder so it doesn't get hurt by weather. Got out my fixture. (Took some searching. It was hiding!) Set the 1st plate on the fixture and dropped the 1st stud into its hole so I could press it home. .... ... :shock: The stud dropped almost all the way home from its own weight. A tiny push of my finger and it was bottomed out head against the plate. Picked up the plate and put them all in the holes. Had to keep the plate turned so the studs wouldn't fall out.

So...
I welded all the studs to the plate and ground off any weld that was standing higher than the head of the stud. Assembled them on the car and all works fine.

But it's not right.

So I called EMPI and the guy I need to talk to was out for lunch. Time for me to call back and talk to him.

I don't expect them to replace any merchandise or pay me money or anything like that. But others should NOT have this problem.

Tue Apr 14, 2020 5:01 pm

Hmm I haven't had that problem. Is your drill bit and drill press really wobbly??

I used the same 9/16" bit for two cars, doing drums and discs, and the EMPI studs, and they all took considerable pressing force.

Tue Apr 14, 2020 5:04 pm

This is what Dorman says about press in studs...

It has been suggested in "wheels and tires" forum to use a piloted end reamer (spot face reamer) to machine a flat in inside of drum so head of stud seats flat ... Also provides a little more clearance for brake parts... You can take standard lug bolt and bore a hole centered of it for "guide" for piloted reamer (threaded in as normal) ... All this "machining" can be done in drill press....

Some of this information is many years old and may not even be accessible in tires and wheels forum...

And of course a good press ...

Dale

Tue Apr 14, 2020 8:15 pm

Matt Wilson wrote: Hmm I haven't had that problem. Is your drill bit and drill press really wobbly??

I used the same 9/16" bit for two cars, doing drums and discs, and the EMPI studs, and they all took considerable pressing force.

Nope! Not a wobbly drill press or drill bit. Not a hand held drill. Like I said, this aint my 1st rodeo. I know how to do it and do it right. Yes, the bit is the correct 9/16" as specified in their catalog page for the item.

The problem is that these new studs have smaller splines than older ones. The product is not the same as before and the instructions offered in their catalog have not been updated to match.

I didn't get in touch with the guy at EMPI today. Try again tomorrow.

Tue Apr 14, 2020 11:45 pm

I tack weld the studs even when they press in well. I always used 9/16 also and have never had to ream. I have installed Jegs studs the same way. Had a few in the past loosen up without a tack. PITA, so I just made it a practice.

Wed Apr 15, 2020 4:57 am

I have heard of 2 different sizes in the knurl's, measure first, possible the drill is a little dull, or if it has been resharpened it was sharpened off center, it will cut over size a couple thou, a drill will always cut a larger hole then its size, reaming is the best bet for true hole size, I have some studs that measure ok for 9/16 they are .577, what did yours measure?

Wed Apr 15, 2020 7:43 am

Best to always measure product once in your hands because some time printed instruction are poorly translated by whomever wrote the instructions is not a machinist or fabricator that understand tolerances....

I sort of like the instructions Dorman Products puts out "hole size should be .017 to .027 smaller than the knurl area"... Sort of leaves up to fabricator/machinist/mechanic to determine correct sizing....

And yes been known to do a bit to tack weld to insure stud does not rotate due to poor hole sizing (interference fit)..

Dale

Wed Apr 15, 2020 12:38 pm

Bought lugs for the rear of a Windstar van, just off the shelf Doorman items. They were the ones in stock.

Al

Wed Apr 15, 2020 2:17 pm

Big Al wrote: Bought lugs for the rear of a Windstar van, just off the shelf Doorman items. They were the ones in stock.

Al

Was interrupted. Sorry. I forgot what drill I used for the holes, but what I did is drilled a 4 lug drum, pushed in the studs. Bolted on a 5 wide adapter and drilled 5 holes and pressed in the studs. Put washers between the adapter and drum and now use 5 wide wheels. No problems so far.

Al

Wed Apr 15, 2020 4:42 pm

Big Al wrote: Big Al wrote: Bought lugs for the rear of a Windstar van, just off the shelf Doorman items. They were the ones in stock.

Al

Was interrupted. Sorry. I forgot what drill I used for the holes, but what I did is drilled a 4 lug drum, pushed in the studs. Bolted on a 5 wide adapter and drilled 5 holes and pressed in the studs. Put washers between the adapter and drum and now use 5 wide wheels. No problems so far.

Al

Here is another one of my rails. Same mod but used the stock lug bolts in the 4 holes.

Al

Wed Apr 22, 2020 12:09 pm

I just measured some Sway-A-Way lug studs I have (didn't have enough for the job in the Baja which is why I didn't use them). The spline major diameter is .578", which = 37/64", or the same as the size as the hole that BugPack always recommended for their studs and .015" larger than the 9/16" (.563") that SAW always recommended for their studs.

After I reamed the holes in my adapter plate to 9/16" and before I welded the studs into the holes, I measured the splines. Of course, I SHOULD HAVE measured BEFORE reaming the holes. The diameter of the splines on the studs I bought was .565". That's a HAIR over 9/16" and awful close to the 14mm thread diameter (14mm = .551"). 0.565 - 0.551 = 0.014" difference from thread diameter to spline diameter. It's even too close for the Dorman spec of -.017 to .027". But then there are different sorts of splines on lug studs. So that Dorman info is not necessarily universal. STILL...

So I called EMPI US again 4/16:
Spoke to Henry. Told him my story. Said I didn’t expect them to replace any merchandise, but that there NEEDs to be clear instructions for customers with CORRECT info on what size to ream the holes. Suggested at least stickers be applied to packages and the info in the catalog be updated. He didn't tell me I was wrong or try to make excuses. He said it IS a problem and he will pursue it.

So BEWARE Samba Offroaders...
MEASURE those EMPI studs before drilling. It they're .565 like mine, drill to 35/64" or .550" (13.97mm). Pretty much a bastard size which will be difficult to find except at a machine tool supply house. And probably not very common there either. Probably 14.0mm would be the closest. But provides less interference fit so will be more needful of welding the back side of the head to the drum or adapter plate. Metric drills are tough to find in the US. Again MAYBE at a machine tool supply.

Wed Apr 22, 2020 12:30 pm

dustymojave wrote:

After I reamed the holes in my adapter plate to 9/16" and before I welded the studs into the holes,

Why weld the studs?

Al

Wed Apr 22, 2020 12:39 pm

Big Al wrote: dustymojave wrote:

After I reamed the holes in my adapter plate to 9/16" and before I welded the studs into the holes,

Why weld the studs?

Al

Because if you do not have good interference fit for spline/knurled area into drum/adapter (hole to big) they will spin in hole and its a a S#!* job to get lug nut off....

And it does not have to be full weld, only a tack weld will do...

Dale

Wed Apr 22, 2020 1:19 pm

Dale M. wrote: Big Al wrote: dustymojave wrote:

After I reamed the holes in my adapter plate to 9/16" and before I welded the studs into the holes,

Why weld the studs?

Al

Because if you do not have good interference fit for spline/knurled area into drum/adapter (hole to big) they will spin in hole and its a a S#!* job to get lug nut off....

And it does not have to be full weld, only a tack weld will do...

Dale

One time I was pulling a camping trailer and the lugs were loose. Wheel came off, broke or damaged all the studs. Got to a small town and removed the drum, someone had welded the studs to the drum. Took about 5 minutes to knock them out with a 2 pound hammer and a big punch. Luck was with me that day.

If you look through the Dorman catalog you can find about every imaginable stud.

https://www.dormanproducts.com/pages/products/wheel-hardware/index.aspx

Al

Wed Apr 22, 2020 6:29 pm

I’d like to see your welds. I tried it once and they won’t take, the drum material was too porous.

Wed Apr 22, 2020 7:36 pm

That would require removing the drums to show them. Cast iron is not in general a good material to weld to. Not a matter of porosity, more one of metallurgy. It should be done with a high nickel rod or wire. Brazing works well though. However, in this case, I was welding studs to 4 lug to 5 lug adapter plates made of steel plate.

Mon May 04, 2020 11:04 pm

This was a result of assumption, Bourbon, and Milwaukee 750 ft lb impact.
I just drilled it to 9/16 and went to town LOL

Tue May 05, 2020 6:37 am

tobiism wrote: This was a result of assumption, Bourbon, and Milwaukee 750 ft lb impact.
I just drilled it to 9/16 and went to town LOL

That is why we have measuring tools and instructions.... NEVER use a impact... Hydraulic press only...

IF you read the instructions supplied out of Dorman catalog, it's better than some Chinglish translation on EMPI package...

https://www.thesamba.com/vw/forum/viewtopic.php?p=9326627#9326627

Dale

Tue May 05, 2020 7:33 am

Dale M. wrote: tobiism wrote: This was a result of assumption, Bourbon, and Milwaukee 750 ft lb impact.
I just drilled it to 9/16 and went to town LOL

That is why we have measuring tools and instructions.... NEVER use a impact... Hydraulic press only...

IF you read the instructions supplied out of Dorman catalog, it's better than some Chinglish translation on EMPI package...

https://www.thesamba.com/vw/forum/viewtopic.php?p=9326627#9326627

Dale

Unfortunately a press was not an option in this instance. With the one piece rotor there's no way to press it in from behind

Sun May 17, 2020 10:17 pm

I agree that using a press is not a good option here. And I really don't like those disc brakes because the hubs are likely to break offroad.

But what are those studs you're using? Pretty DAMNED short!