One of the main reasons I chose the Hammer A3-31 combo jointer-thicknesser what they supposedly were able to thickness material without any snipe. I know, it seems almost too good to be true, but was comforted by several owners whose reviews I trust to be balanced and truthful. Another reason, was that these machines are able to have pretty much every facet of their operation adjusted. It was then with a bit of sadness that my new machine produced snipe when I received it. Knowing however that with a bit of time and a methodical approach I should be able to rectify it, meant that I wasn’t really that concerned. I live in a different state to the dealer, and there is 250 km of ocean between us, so it was impractical for them to come and adjust it for me.
There is no official information (that I could find) and very little unofficial information on exactly what to adjust and how, so have documented the process here for anyone else with a similar need. I was pointed in the right direction by the helpful folks in this thread at Sawmill Creek, so be sure to have a read there too.
It’s probably a good idea to note what I expected to be able to achieve before commencing any fix. I did ask on several forums with current owners first, so that I had a reasonable expectation that the following were achievable:
- Zero snipe. Not just reduced snipe.
- I shouldn’t need to lock the height adjustment (you know, the little lever below the crank handle).
- I shouldn’t need to support the timber, both at in-feed and out-feed.
- Consistent results on hard, soft, long, short, narrow and wide boards.
- Consistent results regardless of cut depth.
My machine produced snipe on both the leading and trailing ends of the board. I would say about 100 mm. The only way to not get snipe was to take very shallow cuts in the order of 0.5 mm. Even then, it was hit and miss if I would get snipe or not.
Checking the roller pins, and their movement.
For the rollers to excerpt pressure on the piece of timber, they are spring loaded. To function correctly, they need to be able to move freely. So the first test is to manually verify their movement with a piece of thick timber.
To do this, I took a 90 x 90 mm piece to timber, placed the tip on the roller, and levering against the table, checked that each of the four pins were moving cleanly. Note, that on the in-feed side, the anti-reverse fingers get in the way, so I laid a small peace of timber on the end of the lever timber to clear the fingers. Had there been any issues, I would have cleaned them and applied a light coat of grease or other lubricant. This wasn’t needed however.
Adjusting the roller tension
As noted earlier the rollers are sprung, and therefore the tension can be adjusted, either more or less. My initial thought was that snipe was being produced by not enough tension, but more on that in a second.
First we need to access the adjustment points. To do this, drop the table low enough to provide easy access to the access ports. To find them, look for black plastic covers directly below each end of both the in-feed and out-feed roller (four total), and remove the covers with a small flat head screwdriver (or some such).
Once the adjustment ports are revealed, you will find a nut and a bolt. The lower bolt head will adjust the roller height, whilst the upper nut will do the spring tension.
I never touched the roller height adjustment, but would imagine that were my rollers not a consistent height side to side, they may need to be adjusted.
When adjusting the spring tension, I made a special effort to:
- Maintain the same amount of adjustment on each end of the roller. Not doing this would result in uneven tension on the roller, and potentially lead to timber stock not tracking squarely through the machine.
- Keep track of the adjustments I made. To do this I made all changes in sets of eight rotations (what the spanner would allow in one throw). That way I could get back to the starting position, but also track the quantum of adjustment made.
With respect to the adjustment itself, I had no idea if I needed to increase or decrease the spring tension, but as they were already VERY tight, the most adjustment would come from loosening the tension, so that’s what I did. If it didn’t work, I would have gone the other way. As long as you keep track of your changes, you can always get back to the starting point. I think in all, I made sixteen rotations on the in-feed roller, and twenty four on the out-feed. Naturally this will be different for a different machine.
With each change, I ran a piece of timber through the machine to check my progress. I used a tall length of framing timber, so that the adjustments remained accessible for successive change-and-test iterations. I found that I could detect snipe by feel even when it all looked OK (but then I wasn’t wearing my glasses).
Once there was no more snipe, there was a part of me that wanted to keep adjusting things, but had to be rather firm with myself, as this is traditionally when I mess things up. Besides, if it’s perfect, there is nothing to be gained by tinkering (other than the joy of tinkering itself, which I quite enjoy).
As a final test, I ran a bunch of boards through the machine, many with full light and full depth passes to verify that my results were repeatable in different scenarios. As such, I tried thick/thin, long/short, hard/soft, light/heavy passes. All with perfect results!
In summary, I can now:
- Plane with zero snipe. Not just reduced snipe.
- Not lock the height adjustment.
- Not need to support the timber, both at in-feed and out-feed.
- Get consistent results on hard, soft, long, short, narrow and wide boards.
- Get consistent results regardless of cut depth.
All in all a great result, which I’m very happy with.