Feed on
Posts
Comments

I recently acquired a new shaper (and a quest machine). It’s a Baxter Whitney No. 89. This is the largest of the single spindle Whitney shapers. These machines have huge tables and are bullet proof. I already own one No. 89, but this one is… well… special… What’s really unique about this machine is the overhead bearing support on the spindle. This allows the use of very large heads and very heavy cuts without deflection in the spindle.

Here’s a close-up of the overarm (outboard) bearing assembly. The lock collars on the support bracket allow the bearing to rise and fall with the spindle:

On first observation, the spindle appears to be proprietary. After disassembly, it becomes clear that the shaper uses standard spindles which can easily be changed out for different sizes:

.
.
.
The trouble with this machine and most big American made spindle shapers is the lack of a fence. In most cases, this machine would have been used with rub collars or had a makeshift shop-made fence clamped to the table. I’m a big fan of the European style shaper fences. In particular, I really like the fences on the SCMI heavy duty shapers. I’ve done allright over the years buying SCM basket case machines and stealing the fences from them.
.
.
.
Here are a few pictures of the SCM fence I’m most accustomed to:
On a Invincible T120 Shaper

On an SCMI T100 Shaper

And.. another view of the same fence

.
.
.
.
This got me thinking about what it would take to build such a fence from scratch. The design is pretty simple. A robust cast iron body with a heavy split fence of which the two sides can be adjusted independently. The fences are attached to steel bars or tubes that pass through the body and can be fine adjusted with a handscrew. The bars would need to be of a substantial diameter (2″+) in order to cary the weight of the fences and be robust enough to withstand deflection caused by pressure from a feeder.

As stated above, I really like the SCMI design. However, there are a few things I don’t like. most notably, is the split side where the fence support bars pass through the body. These are split to allow the fence tubes to be locked into position by compression of the opening with a large handscrew. I’ve seen many cases where these were cracked or broken from overtightening or fatigue. This is also a difficult feature to cast and machine.
.

I decided to come up with another approach to this feature.

.

My final design combines the features of the SCMI fence with those of the early Jet fences. Now the only thing left to do was create a pattern. I did this in a two step process. The initial pattern was made from cedar blocks and then sent out to the foundry to be cast in aluminum. I then took the aluminum casting and tweaked it to represent the final design and sent it back to the foundry to be cast in iron.

.
Here are a few pictures of the rough casting:

As mentioned, it’s heavy. Weighing in at just over 50 Lbs.

It’s a hollow core and is internally reinforced to avoid stress, fatigue and failure. Particularly around the bores for the fence support bars:

So this looks like a pretty good start..
Right?
Not so fast.
This is where the title of the article comes in…

It was only after I got the rough castings back that I realized how big a job this would be to machine. The big problem is with the bores for the fence support bars. The body of the fence is almost 8″ deep. Ideally, you want to do the bore directly through in one pass to avoid issues with mis-alignmemt.

As an aside, this reminds me of a conversation I once had with the owner of a US based woodworking machinery manufacturer. I had disassembled one of their big jointers and noted that it had three double-row self-aligning bearings on the motor/cutterhead. I thought that these were mistakenly installed as replacements. The owner corrected me and said they were indeed the original bearings. When I asked why they used these bearings, he explained that they didn’t have the machining capability to run a bore that long in one pass. Rather than retooling (way too costly), it was easier to just let the bearings correct the alignment issues.

Now I know that these bars don’t require the precision of a cutterhead, but I’d like to get it as close as possible. And the engineer in me wants to do the bore in a single pass. My ToolMaster mill only has 4″ of quill travel. This means that the bore will have to be run using the knee movement rather than the quill. That’s a shame since I have a power quill and it’ll be alot of hand-cranking. The next issue is the diameter of the bore. The design calls for 2-1/8″ bars to support the split fence. That’s a big hole to push through in one or even several passes. It’ll need to be done in a stepwise fashion using a combination of drills, end mills and boring tools.

The rest is easy (relatively speaking). The bottom (table side) needs to be flattened. The two sides will need to be squared with the bottom. Finally, the bars will need to be turned on the lathe and the split fence will need to be cut and finished. Then there’s a bunch of small stuff for fasteners, adjustments, etc.

View the video on the concept and rough casting

Stay tuned here for the next installment on this project. I’ve already accomplished a great deal. I just need to get it documented and published.

-the owwm

5 Responses to “Stretching the limits (or when your ideas exceed your capabilities) part 1: the problem is the inspiration”

  1. bob kloes says:

    Good morning Arthur. Looks like another fine addition. I watched the video and have a question. Will the fence have enough room to fit with the wood faces between the upper bearings and the spindle? It looked in the video that it would be sitting sticking way past the spindle. Must be the camera angle. Always enjoy your posts. bob

    • The owwm says:

      Bob,
      Yes. it’s the camera angle (it’s mounted on the ceiling). There’s plenty of room there. Even if I were to use 6″ faces, that would leave me another six inches of clearance. You did just make me consider a nice feature, which would be quick detach faces that could be changed out on the fly for any job.

      Thanks,

      -Arthur

  2. Rich says:

    Art,

    I like the design of the No. 89, with the outboard bearing support on a good horizontal mill. Fence casting looks very substantial, too, fitting well with the character of the machine.

    Looking forward to watching the progress.

    Rich

    • The owwm says:

      Rich,
      Thanks for the comments. I’ve been working on boring out the fence supports this week. It’s a big job with lots of starts and stops.

      -Arthur

  3. J. Vibert says:

    As always Arthur you never disappoint…

    There’s been a few times I’ve been forced to bore large/deep holes with my mill’s knee rather than the power quill. As you say, it’s a bit taunting, but I almost perfer the control the hand work provides.

    At any rate, I look forward to part 2.

Leave a Reply