Drag Specialties is a drag but choices are limited. Other brands are out of stock for these (in Canada) and will be for a while.
3.5" straight risers. Manufacturer claims it's 6061 aluminum but it's a chrome finish on it.



The problem is, the top clamp bolt holes don't go all the way through like most/oem risers do. The stock clamp bolts end up being 1/4" too long. Not willing to cut those bolts. Shorter bolts like that are not easy to find. I have several good machine shops nearby. Reckon it's ok to drill and tap these?

 

Sure you can. You can also definitely get socket head cap screws in Canada, although it may be more challenging in your area if you don't want to order them online. It also takes all of 10 minutes to cut all the bolts off at the bottom just a tad. Not sure why you want to go the most time consuming and expensive route out of all of them.

 

 

Just cut the bolts and you are done with it, much nicer then them sticking out and you are not damaging the chrome as you will do when you are going to dril and tap.

 

Thanks guys. I appreciate the replies.

I should have explained better. The bolts wouldn't stick out the bottom, if drilled and tapped. They would be the same as oem.
I was against cutting the bolts because of safety concerns. Correct me if I'm wrong. Wouldn't be the first time. Would shorter clamp bolts be able to handle the same torque spec?

Socket head screws to fit there are difficult to find locally, if at all in grade 8. if that's what they are.

Thanks again.

 

Your preferred solution assumes there is slightly more than 1/4" of metal in those risers that can be drilled and then tapped. Are you sure you can get the drill centered perfectly?
The other solution is to cut the bolt down and you don't know if you should or if it is safe? A bolt needs to go in at least 1.5 x its diameter, minimum thread engagement.
EDIT: Maybe scrap that in favour of the fact HD came up with a bolt length with a specific thread engagement (unless they picked a bolt off the shelf of a set length over the minimum length that gets the job done). So I would look to keep existing bolt or do the calculations to determine exactly what the minimum thread engagement is into 6061 aluminium.

 

Well I trust Scuba's opinion on this. Not going to overthink it.
I'll measure out 1 tad* and chop that off the 4 clamp bolts.



*1 tad being equal to 1/4" or 6.35mm.

 

I edited my answer because I am not sure and I am not going to do the calculations or guess that it will be okay to just shorten the bolts you have.
It is accepted that a steel bolt into steel only has to thread in as a minimum the diameter of the bolt.
When threading into aluminium it will need to go in further due to the thread strength of aluminium.

 

The engineer who designed the risers thought so.

 

Pretty much the maximum length of holding/gripping power of any threaded fastener is about equal to the fastener diameter. In softer materials like aluminum, or cast iron which is brittle you might go slightly longer.