Hi,

This is my first post to this forum so I hope I am putting this in the right place.

I am working on expanding my darkroom to accommodate 4x5 enlargements. I purchased a Fujinon ex 135mm f/5.6 enlarging lens. At the time I didn't realize that this lens requires a unique 53mm sized flange. I went ahead and purchased a 53mm 4x4 lens board off ebay, but there appears to be some sort of fitment issue. The hole in the lens board appears to be too small to allow the lens threads through. While I don't know for sure, the lens board appears to be a Beseler lens board as it looks just like my other ones. I did a rough measurement with a tape measure of the opening and it appears to be the advertised 53mm size. I have attached some pictures of what I am dealing with. Any thoughts as to what may be going on? I got the Fujinon EX because it was comparable in quality to "the big three" brands while being cheaper, but now I'm wondering if I should have just spent the extra money.
Click image for larger version.  Name: PXL_20210913_212709750.jpg  Views: 28  Size: 80.5 KB  ID: 219610Click image for larger version.  Name: PXL_20210913_212719047.jpg  Views: 28  Size: 54.5 KB  ID: 219611Click image for larger version.  Name: PXL_20210913_212730722.jpg  Views: 25  Size: 46.6 KB  ID: 219612

Note: I am still waiting on my 53mm x 0.75 retaining ring form Custom Photo Tools.

Edit: Upon further inspection it appears that the inside wall of the lens board it tapered slightly. One side of the opening is larger than the other by a small amount. I am not sure why this is or if it is to be expected.