by Tom Gaylord
Writing as B.B. Pelletier

I am not running an historical report today because we have two guest blogs this week. Today I’m running the first of them. This is a guest blog from a reader who goes by the name Motorman.

If you’d like to write a guest post for this blog, please email me. Now, over to you, Motorman.

“Spring Doc” Spring Compressor Review
By Dean Speidel, alias “Motorman”

This report covers:

  • Decisions
  • “Spring Doc”
  • Diving In!
  • Flies in the ointment?
  • Wrap-Up

Decisions

For some time I’ve been thinking about learning to disassemble, repair and, perhaps most importantly, re-assemble spring piston airguns. Making or buying a spring compressor is the first and unavoidable step.

I’m reasonably good with my hands, so I searched the internet and found a number of plans for build-it-yourself compressors. Some were pretty crude and, frankly, looked dangerous! Some were better, but I just never found one that I liked well enough to put the money and effort into building it.

Then I started looking for complete spring compressors already made up. A little more expensive, but expedient. Again, some were well thought out, but others seemed less, umm, impressive. Some were just flat out expensive.

My research at least helped me to figure out what was important — first, it needed to be as safe as possible. I didn’t want anything that was likely to damage me or the air guns I was working on.

Next, the easier it is to use, the better the result, and likely, the safer it would be. Since I would be working on both pistols and rifles, I wanted something that had a pretty broad range of adjustability…short to long guns, some with a pretty extreme range of preload.

I also wanted a compressor that would stand by itself and not have to be secured in a vice, clamped to a bench or something. My vice is in the garage and it’s too cold to work out there at this time of the year. It needed to sit by itself on a table or desk.

And, it needed to be both affordable and available from stock. I once had a boss that told me I could have it cheap, I could have it good, or I could have it fast, but I only got to pick two of the three. Well, I wanted all three here!

Spring Doc

About a year ago I was looking thru the online air gun ads, and there on the American Airguns websitesite was a spring compressor that seemed to fulfill all these requirements. It’s made by Greg Lindsey out in California. He calls it the “Spring Doc”. It looked well-made in the photos; I liked the design, and I thought the $150 price tag (plus shipping) was reasonable. It’s available in different woods; ash, African Sapele, African mahogany, and hickory. I took the leap and ordered the hickory one.

Spring compressor labeled
These are the parts of my new spring compressor.

When it arrived my first reaction strengthened the impression I’d gotten from Greg’s ad. The craftsmanship was excellent! The hickory base is 5” wide, 2” thick, and 36” long. All wood surfaces are smooth, corners are radiused and everything is given a nice polyurethane finish. The aluminum rails for the barrel clamp and compression block T-bolts are beautifully flush-inletted into the wood. The holes for the stop pin are nicely chamfered. The hardware seems heavy duty throughout…in fact, the compression block screw rides on an industrial bearing block! The aluminum braces for the head stock are made from ¼” X ¾” bar.

I really liked the nice, thick rubber bridge for supporting the gun’s spring tube. It improves safety for the user while helping to avoid scratching the bluing, and it couldn’t be easier to adjust for different guns. The rubber bridge can be screwed up or down into the base, while the strap has several notches to accommodate different spring tube diameters.

Reinforcing the impression of being a heavy-duty tool is its weight! Mine weighs 21 lbs.! I wanted something stable and this is it!

The adjustability is also a plus. The compression screw moves the compression block thru 7” — I can’t imagine that there’s a gun out there with more spring pre-load than that! The barrel clamp provides another 7 ½” of travel on the other end to adjust for different spring tube lengths. While it didn’t come with an instruction manual, everything seemed pretty intuitive to me.

Diving In!

My first victim was a well-abused 1960’s-era Diana model 5 pistol that I purchased just for this attempt. I figured if I screwed it up I didn’t have too much to lose and it should be a relatively simple gun to disassemble and then get back together. I first removed the wooden stock from the spring tube.

Mounting the gun in the spring compressor was pretty easy. This is a relatively short spring-piston pistol, so I loosened the hand wheel to retract the compression block (on the right) enough for the spring pre-load this gun is likely to have.

Next, I removed the barrel clamp thumb screws and took the top off. I noted that the top and bottom jaws of the barrel clamp have a felt lining to prevent scratching the gun’s finish! That’s a nice detail touch. I put the spring tube in the rubber support [The bridge? Editor] and adjusted it up and down until the gun’s spring tube and barrel are level and making full contact in the barrel clamp grove.

Diana 5 in compressor
My Diana model 5 pistol is in the compressor.

Then, I positioned the back of the spring tube against the compression block. I also noticed that the compression block has a felt surface to prevent marring the end of the air gun — even if you have to rotate things while they’re under compression. Again, a nice detail touch.

I placed the barrel in the slot on the barrel clamp, replaced the top and lightly tightened the screws…not too tight because we need to slide the barrel clamp until we find the approximate lateral position and insert the safety stop pin into the appropriate pre-drilled hole. Seat the spring tube against the barrel clamp and finish tightening the barrel clamp screws. I don’t think it’s necessary to clamp down on the barrel too tightly because the end of the spring tube being against the barrel clamp is enough to keep it from sliding.

We can now start screwing the hand wheel in until a moderate amount of pressure is placed against the end of the spring tube. Remove end cap set screw on the gun, or the retaining bolt, or whatever secures the end of the spring tube. Then gently rotate the hand wheel counter-clockwise to release pressure on the gun’s mainspring as you unscrew the spring tube cap (or whatever the right procedure might be for your gun) until the spring has gone slack. Now you can remove all the pieces from the spring compressor!

relax tension
The gun’s mainspring is now relaxed and the action may be disassembled.

Re-assembly is pretty much the proverbial “assemble in reverse order”.

I later dis-assembled and re-assembled a Feinwerkbau 124. The compressor was easy to adjust for this much-longer gun and the spring stop’s hand wheel screw had plenty of range to release the 4” or so of pre-load this gun has.

Are there any flies in the ointment?

When I disassembled a pre-WWII Diana Model (V), which was even shorter than the Diana Model 5 in the photos, I found it necessary to drill an additional hole for the safety stop pin. It was no big deal and Greg tells me he’ll be drilling this additional hole in all future Spring Docs.

As with any spring compressor, some allowance has to be made for guns with the safety on the back of the spring tube. This wasn’t a problem on the Diana Model 5 p;istol, but I had to roll up a piece of cardboard and put it on the back of the Feinwerkbau 124’s spring tube. Some of the Dianas that have a safety release on the back of the spring tube (i.e. Models 34, 36, 48, 52, 54…more?) will require some additional creativity to avoid putting too much pressure on the safety and breaking something. None of this is unique to Greg’s spring compressor.

Wrap-Up

The “Spring Doc” spring compressor (made and sold by Greg Lindsey in northern California, email: [email protected]) is well-designed and well made. I particularly like the safety features built into it. It seems to work well on a wide variety of spring piston gun designs. Would I buy it again? Yep!