The top of a classic slimline pen consists of a press-fit cap that fits into a ring on the clip prior to being pressed into the top of the pen tube. The outside diameters of the cap and the clip ring are the same as the bushing that the pen was turned to. Ideally, there should be a smooth transition from the wood (or other barrel material) to the top, and you shouldn’t really be able to tell that the clip ring exists. This is in part due to an extra ridge on the cap portion that centers the clip ring. This is supposed to be an extrememly close fit.
Recently I purchased several custom clips for a special order. Sadly, the clips do not have the same fit as the ‘stock’ clip. The diameter of the cap is 6.30mm at the base, and 6.90mm on the centering ridge. At 7.0mm inside diameter, the stock clip makes a snug fit inside the clip. The custom clip inside diameter is only 6.25mm, however! As is, the cap and clip won’t fit together at all. I thought that maybe I had purchased the wrong kit for those clips, but they were just listed as “clips for slim style pens”, and I even checked another kit to see if they would fit. Nope, they are simply made to different specs than the clips they are meant to replace. This presents problems since I have an order to fill. Let this be a heads-up for anyone else turning pens with a custom clip. Make sure that the clip fits prior to leaving the store if you buy it in a bricks and mortar shop, or before you buy more than one if you buy online.
The solution to my immediate problem has come in the form of the Dremel. For each pen, I have been carefeully grinding the inside of the clip ring until I am able to widen it enough to get the cap inside. This is a slow process that has a chance of cutting all the way through a clip ring, rendering it useless. I’ve been lucky on the few I’ve done so far, but I have several left to do, so wish me luck! On a positive note, the outside diameters appear to be equal at 8.40mm, so this solution will suffice if I don’t break any. I will bring the issue up to Woodcraft’s attention, and hopefully they will follow up with their suppliers in Taiwan to correct the clip size. I have no idea if this affects other novelty clips, or just the gold medical clip that was required for my order.