I’m back. Yes, this blog lives. Over the past 2 months I’ve been through some tough challenges I do not care to relate in public, and am just returning to ‘normal’ – whatever that is, so hoping to be back to normal operation, both in the shop and blog-wise, over the upcoming few weeks.
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From the previous post in this thread, you may remember that I had the sliding table on the saw re-planed flat, and along with that the front mitre gage was also planed to make it geometrically correct, and was fitted with a new pivot bolt. Additionally, the worn detent holes in the table were plugged and re-drilled with a tapered cutter, and a second position for the mitre gage was made in the mid-length point of the sliding table.
As to why I would take the time and trouble to do this? Well, I like shit to work properly for starters, and I notice when it doesn’t. A bowed sliding table means that rip cuts with stock which rest partly upon the sliding table side (i.e., most rip cuts) end up riding up on the bowed of the sliding table, taking the cut out of 90˚ or whatever else angle was desired. Some might tolerate the disfunction, but I could not. Though I was considering, and still do consider, buying another saw altogether, I felt that at the very least I should try to put the saw right and see how I liked it – – and if I still want something else after that then I can sell it in good nick, as some Brits might say, leaving me in better repair than I found it, and definitely salable for more than it would be otherwise.
Anyhow, part of that repair work, as mentioned previously, was getting the front miter fence corrected geometrically and positionally, so as to do its job as intended. As the term ‘front mitre fence’ suggests, there was also a ‘back miter fence’ available for the Wadkin PP dimension saw, however it was optional and seems to have become rarely optioned, so it is now a quite rate accessory. You can see it in Fig. 6 (bottom left) in the brochure for the machine shown below:
The back miter fence is employed in tandem with the front miter fence to effect cuts for mitre joints in polygons of any number of sides. This type of double miter fence was seen on other saws of this type, but seems to be a rare accessory regardless of make. One factor playing into that is that the casting for the Wadkin back miter fence was not robust enough to withstand drops to the floor, and breaking of the guide slot was not an uncommon result. So, of the back miter fences which were supplied, there has been a certain attrition over time, and of course it is not uncommon when machines change hands that parts, manuals, and accessories get lost in the shuffle. I’ve tried finding an original manual for a Wadkin PP saw and had no luck so far, for instance. Where’d they all go?
The pairing of front mitre and back mitre, when in the 90˚ relationship, produce of course a quarter-circle, and thus the N. American term for the pairing of front/back miter fences is “quadrant”. For some strange reason, in recent years this term is now being applied to just the more common front miter fence alone, though is then becomes a bit nonsensical in my view, as a front miter alone does not a quarter circle describe.
Notice in Figure 7 above another type of fence, termed by some a protractor, what is otherwise termed in N. America at least, a ‘miter gage’. The brochure describes it as:
“For work involving only a small movement into the saw, fast production can be obtained with this sliding fence supplied to order. Tables are tee-slotted both sides of the saw to receive this fence.”
Like the back miter fence, the protractor is a rare accessory. One fellow in England who frequents a Canadian Woodworking forum dedicated to vintage power tools, mentions have searched in vain for 6 years for the protractor, to no avail. And he lives in the UK, where Wadkin stuff in general is going to be a lot more abundant than it is in N. America.
Fortunately, some other members of that forum have gone ahead and cast reproductions of both rare accessory fences, and I now have obtained each, in rough-cast form.
The front/back miter fence set greatly facilitates cutting miters, so it is obvious as to why it would be nice to have that set. The reason for having a protractor however is less obvious, however if you have a saw which tilts only one way (like most, but not all saws), then angled cuts can then be taken on both sides of a blade. Otherwise the single tilt capacity is a limitation. So, I’m planning to use the protractor in the t-slot which is in the main table of my saw, to the right of the saw blade, and continue using the front miter fence on the left side of the blade, on the sliding table.
Another advantage to having a sliding fence on the right of the blade is that the two fences on each side of the blade can be linked to one another with a connector to create a sled-like cutting arrangement. Anyone who uses a table saw knows the advantages of a cutting sled.
I noticed that some American-made dimensioning saws in the distant past (early 1900s~1920s) came with such capacities, and there were even protractors for both sides, one with an angled portion removed so as to clear the blade, and a horseshoe-shaped cast connector:
The above photo comes from a web page devoted to the topic of Oliver miter gauges. The bridge between the two fences in interesting. Here’s a close up picture of one that is for sale currently:
However I’m not sure what advantage it provides relative to screwing a suitably clean flat and square wooden fence right across both gauge heads.
After speaking with my machinist friend in New Hampshire, the same fellow who planed the sliding table for me, we determined that in order to keep costs down for the protractor work I should tackle the rough milling of the castings. Besides the cost savings (which are more or less fictional if I consider that my own shop time is being used), I wanted to have a try at milling cast iron, as it was not something with which I had any experience.
Rough castings I received are made oversize by around 10% and with draft, which is a taper to the pattern to enable the pattern to be easily removed prior to the molten iron being poured. This left me, especially with the protractor casting with its semicircular beveled protractor edge, with a tricky piece to machine, in that there were no easy ways to fixture it to the table.
The base of the rough casting was 0.9″ thick or so, which, given that the finish dimension was to be 0.75″, left me with ample material to play with. I initially fixed the bottom of the casting down onto a pair of blocks and took a light skim on the upper surface, only to come face to face with the fixturing challenge. The hold downs that I used to hold the casting to the table were in the way of the cutter, so had to be moved around from time to time and this lead to a imperfect surface.
Take 2, then.
I got a piece of MDF, and after playing around with positioning the casting a bit I used some PL300 construction adhesive to affix the base of the casting to the MDF:
Casting now in place, and I let it set up for three days as things turned out:
The casting for this miter head is massive by any standard, certainly multiples greater in size than the typical miter gauge you see on a cabinet saw.
This worked very well, and I was able to deck the upper surface without issue:
I gave the top edge of the fence a little attention while I was at it:
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