Posted by DDH Staff on 4/27/2023 to Tips

If you’re renovating or updating an older home, then you may have noticed that your doors have non-standard bore holes. You’ve probably also noticed that it’s very difficult to find a door knob for small bore hole. We know that dealing with unprecedented hardware issues can be difficult, so we thought we’d put together a short guide to navigating this situation. In this post, we’ll share a few of our tips for finding door hardware for small bore holes, including a few ways you can alter your existing bore holes to make them more accommodating for standard knobs.

Are There Door Knobs For Small Bore Holes?

A common request we get at Direct Door Hardware is for door knobs or levers made for the small 1-1/2 or 1-5/8" bore hole. The truth is, while there are deadbolts made for the smaller bore hole, today's knob and lever sets are generally made for the standard 2-1/8" bore. The exception would be mortise lock hardware or high-end custom hardware like Baldwin Estate Series. However, if you aren’t wanting to splurge on custom hardware, you have a few options.

Ways To Adjust Small Bore Holes

The first thing you can do is purchase a door boring kit to re-bore your doors. These kits include a jig to make sure the hole saw drill bit is drilling in the correct place. They also typically include both sizes of drill bits you need – 2 1/8" (main bore) and 1" (cross bore). Once your doors are re-bored to standard sizes, your options are far and wide for the style of knobs and levers that will fit your door. Many people shy away from this option, but we believe this is the best solution.

Your second option is to modify your existing bore holes. We’ll use the Schlage door knobs and Kwikset door knobs as an example. Most of these door knobs will have a cast aluminum insert that requires the hole to be drilled to 2-1/8". If this is the hardware you want to use, then your only option is to cut the existing bore hole to 2-1/8”. If your bore hole is already drilled at, say, 1-5/8", it’s tough to re-drill it bigger because hole saws require a pilot bit to keep them centered and cutting straight. You can still do it, but you will need a solid jig clamped to the door to keep the hole saw in place. If you're only doing one door, you could carefully cut the hole a little bigger with a jigsaw, but that method is relatively time-consuming.

More Tips For Dealing With Small Bore Holes

Installing a door knob for small bore hole can be difficult, so if you’d like more information on doorknobs that fit smaller than standard bore holes read more on our site or reach out to speak to a door hardware expert. If you have further questions or concerns, go ahead and give us a call. You can reach us by phone at 307-886-9449 from 9:00 am to 5:00 pm mountain time Monday – Friday. You can also shoot us a text at 307-275-9700 if it’s more convenient. Our knowledgeable team looks forward to hearing from you, and we’re always happy to help answer any questions you may have.