Opinions Wanted Hoffman Joiner. Is this cutting it too close?

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Larry Peterson

Larry Peterson

SPFG, Supreme Picture Framing God
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Now that my Hoffman is up and running, I need to decide which wedges to use for the frame that I will most use the Hoffmann for.

The frame is L-3272 from Nelson. The stem width is a tad under 3/8" and the height is 7/8". In the picture below the wedge is a W1 x 3/4. Is that cutting it too close? I could go with the W0 wedge but I would prefer to use the W1 as I can use it for wider mouldings and not have to change the bit just for this moulding.

w1.jpg



L-3272.jpg


L-3272.jpg
 
All you are doing is removing wood with the router bit, then filling in the void with plastic. If it works, as in not splitting the wood when inserting the plastic wedge, then it is fine. I used a Hoffman joiner for years, it is of course not for every moulding but it is one handy tool to have. After Mary bought my business the Hoffman was her primary method of joining. You will grow to love that tool. Don't forget that you can stack the wedges.
 
That isn't too close. You could even go closer. The risk of splitting isn't in the inside of the frame, but the outside. I have cut plenty of keyways 1/32" from the inside edge with no problems. The weak point is between the outward points of the key and the outer edge of the frame. if I'm going to have failure, that is mostly where it happens. It also does happen when the grain of the wood isn't close to parallel to the body of the frame. Curly figured wood will split out as well.

Are you using the tight fit W-1 bit or the slightly over sized one?
The tight fit is fine for soft woods like the one pictured, but if you are using hardwoods, the slightly over sized W-1, and it is probably around 1-3/1000th" we're talking about, is a safer bet for not splitting out the corner.

You can see a slight opening of the joint on the outside of the miter. You need to make the keyway cuts a tiny bit deeper so the key doesn't hold the joint apart, but pulls it together. There should be a slight gap between the flat ends of the key profile and the frame.

IMG_0234.jpg
A. Slight air gap (2-3 1/1000th") B. Weakest point of frame
 
Experiment with that a bit, you might only need one key on that width moulding.

I have talked with Marcus at Hoffmann and he agrees that cutting the keyway a little deeper is ideal for getting the keys to pull the joint together. The OS bit is primarily used when the key causes splitting when inserted, and the regular is the default bit. He did say to call them any time if you need help with the machine, and that you might download the PU-2 manual which has updated pertinent information that applies to the X-25 in regards to set up, etc.
 
I have two machines set up for W0 and W1 bits. The W0 keys are tiny and fiddly, so I use the W1 machine as often as possible.
Like Wally said above, cut the keyway closer to the inside of the joint to avoid splitting and you should be fine. I've only had a few frames split when inserting the key and it was always because I cut the keyway too close to the outer edge.
This is a wonderful machine and I use it more often than my V-nailer. There is a learning curve, but it is slight.
And again, like Wally said above, don't hesitate to call Marcus, he is super helpful and responsive.
 
W1 can theoretically go down to a 5/16" stem. It should be fine on the 3/8.

BUT. The joint will be strongest if you place the slot as close to the INSIDE of the moulding as possible. It can even come right to a point and I will almost guarantee that if you break the joint, it will still break on the outside.
 
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