OK, I'm going to replace the torx screws on my derby cover with allen screws.

But, which is better: the allen head screws or button head screws? Other than looks, is there a difference? Seems to me that the allen head have a larger area, and therefore would be more solid and easier to use.

Also, I know the screws are 1/4 - 20, but what length for 2010 Ultra? Are they 3/8", 1/2" or 5/8"?

Thanks in advance!

 

No real difference your more likely to over tighten allen head. And over tightening derby covers seems to be something that happens a lot.
Only real reason anyone has issue with Torx is they use the wrong size trying to remove them.
See it all the time they try to use a 25 when it calls for a 27.

 

Yep, I've heard that many use the wrong size, and I do have T27's (Craftsman). But, dang those things are in solid! I'm going to pick up an impact driver to see if I can get 'em out without goobering them. Once I figure out how to get the darn things out safely, I will be torquing them to spec.

 

I have been doing this for some time and have learned not everything needs loctie and over torquing The derby cover
I use a 1/4 in ratchet with head between fingers snug it up and stop never have any problem.
I do replace the stock ones with ss or chrome just beacuse I like the way they look

 

I put the allens in on my dyna and will never go back to the pia torx. Mine took 3/4" length. Just take the top torx out and take it with you to true value hardware. Cost $2.

As for overtightening them....100 inch lbs is the middle of the range and works just fine.

 

I use stainless button head allen bolts because they offer a similar head diameter and profile to the stock torx. I used 5/8 inch length on my two bikes (Street Glide, Street Bob). The main reason for going this route was to either replace damaged bolts (on the Street Bob, I bought it used) or to improve the look (cad plated stock torx with the chrome primary on the Street Glide not so good looking).

I use a lock washer, blue loctite, AND an inch pound torque wrench when tightening these screws. Have not had any problems with this method. The bolts don't loosen over time from vibration and I don't have any problem getting them loose for service work. I think the guys that are having problems getting the derby screws out are over tightening them.

 

About 75 in. lb. would be the max for a good grade stainless 1/4x20 bolt (80,000Psi tensile strength). Who knows what quality lurks in the hardware store bins...

 

it's the same quality that lurks in the dealers bins. i doubt the dealers buy overpriced moco nuts and bolts. they probably buy from the hardware store and charge moco list price.

 

What makes you think that? You think the dealers are scrounging around hardware stores?

Every fastener I have bought from a dealer came in a package with the HD name on it. OEM fasteners may not be pretty, but they are good quality.

 

i do know the moco doesn't make nuts and bolts. they buy them from someone. i don't know who they buy them from and i don't know where hardware stores get them from. i put stainless allens in my derby cover over 25 years ago, i got them from a hardware store and i never had any problem taking them out or putting them in. are you saying hardware store bolts are inferior to moco hardware? you got a link to that? i never bought a nut or bolt from a dealer so i don't know how they're packaged.