ThomasI have never done a Diana but do a search here and google there are lots of instruction on how to make one far more cheaper than a bought one and in most cases better too.I believe Air Venture sells one for around 100 bucks that clamps to your scope rail. Myself I use a pipe with modified pipe clamps. Does the trick quite well and one size fits all. Frank
I received one of those Air Venturi spring compressors for free, PA was including them with purchase of certain air rifles a while ago. If your gun isn't scoped, then its a very good device. The $100 price tag is a bit much I think, but it does work very well. I've used it on Hatsan's and multiple Diana air rifles. It's compact and quick to use compared to other spring compressors I've used. Keep an eye on promotional deals, sometimes you get neat stuff.
A guy on YouTube doing springers using one of these .Zip zap pow donehttps://www.lowes.com/pd/IRWIN-QUICK-GRIP-36-in-Heavy-Duty-One-Handed-Bar-Clamp/1003168272Just made a deal on one end to fit in the reciver part (a nut?)Plenty of home made ones on YouTube as well to look at for ideas
A Groz (brand) sash clamp will do the job quite nicely for about $50. The jack screw on most sash clamps is too short but the Groz is adequate. If you wish to build your own there are instructions in the GTA library as well as on charliedatuna.com. I built mine out of a 2 X 4, a six inch C clamp, and some assorted nuts and bolts. Note that in addition to the pictures I've attached a document file including instructions and a kind of bill of materials.
I've used a lightly modified harbor freight bar clamp. just dremeled on a bit of texturing to keep it from sliding off.
So far I own mostly PCP's with just one springer, a Diana 34 classic. It is perfectly fine and no issues. From what I've heard and seen on the forum ,the spring will eventually have to be changed.When it comes to spring compressors are there certain models considered better than other's or are there cheap and more expensive models out there like everything else ,for example chinese manufactured? I could use some suggestions on compressors . Thinking I might get one in the near future to have here instead of looking for one later on because I do plan on getting at least 1 or 2 more springers to the collection and will need one around when I need to change one out.