I find it highly important to be able to reliably dial in my machine tools, check parts and inspect to find errors in their machined surfaces or tune. I recently purchased a Wadkin DM mortiser. Upon inspection I found some parts out of tram and needed to be brought into square. My initial thought was to shim the column to bring it into tram, however I decided to inspect the table and machine ways as a first step.
Prior to inspecting the table I setup an indicator to run across X, Y and Z across various parts of the main table. Z provided out by .007″ over the length of the fence. The fence out of parallel to X travel by .012″. I then ran X and Y on the main table surface the table provided out of tram at the ends by an amount I don’t recall and .005″ across the major part of the table.
First point of inspection was the table and saddle, I sat my camelback straight edge on it and the straight edge revealed a bow in the center of the table. So, table must be resurfaced. The table is bigger than I want to machine myself so it’s off to the machine shop.
Next I got the machine down to the fixed ways. I inspected these ways for straightness then I worked them lightly with a hone to remove burrs and take out a very slight out of parallel situation, then sat a try square on the ways in multiple place to compare the head to the ways.
I’m traveling the head the entire length of the machine’s travel.
.0035″ tilted along the side. With shimming I was able to manage .000″ along one way front to back and .001″ along the other.
The back remained slightly out still, but something I can live with.
I reinstalled the saddle after deburring everything, an important part of inspecting.
The outer gib screw was out of proper adjustment and bringing it into adjustment allowed smooth travel and brought the surface into tram, almost. An .001″ bump in the center is showing itself here. Inspection grade blocks are used to raise the square.
After properly adjusting the gib.
At the machine shop the work began by inspecting the table ways on a 4×8 granite with cert. After which it was moved it to a gantry style Haas where they started taking measurements with a test indicator.
The table top was like a landscape, highs and lows all over. The fence was out of square to the table and out of parallel to the ways. I was happy to see numbers very similar to what I found measuring on the machine. .007” out of square and .012” out of parallel.
Their machining brought the fence to dead on square (no change in the indicator) and parallel to .001”. The tables surface was made flat to better than .001″.
Next I dialed in the chisel holder, doing so was surprisingly difficult. I did not expect perfect alignment but I was surprised at the reasons why it was out.
There are many reasons for wanting this square, primarily I do not want the chisel to deflect under load, approaching the piece with the chisel cocked is going to apply a horizontal force to the chisel, bending it.
Inspecting required the installation of a known accurate pin into the chisel holder. I used a pin the same diameter as the chisels I typically use. Using this diameter pin includes the bushing in this measurement. I checked the pin for straightness on my surface plate, rolling it and checking for light between the plate and pin. I also checked for accuracy in dimension on both ends.
At first glance it appears that the chisel holder is bolted up tight, but further inspection provided that one could see light between the mating parts. I decided to indicate it first, as it sat to see where I stood.
I work to set everything in alignment to travel, which is why I first make the effort to set the column square to the base’s dovetails utilizing the travel of the head as my basis. That allows one to align parts to travel, rather than to each other. The limit of accuracy would be the machine ways themselves.
First step was to chamfer all holes and deburr the surfaces at hand. There were some pretty offensive burrs, but they were easily removed with a hand burring tool and a light india stone.
Next, I started to dig in. First thing I found was a sleeve in the bottom of the motor that was proud of the surface by quite a bit.
I filed that back and expected the parts to mate, but they did not still. I applied yellow marking compound to the motor.
At this point I also decided to indicate the spindle to make sure it was actually aligned with the ways. Normally I would use a test indicator here, instead of this dumb approach, but it worked and saved me from driving to pickup my test indicator. I travel the head up and down and look for misalignment.
This was followed by a sweep around the mating surface. I found this pretty decent, a thousandth showing here and there. This ensures the spindle is square to the housing face.
Next, returning to the part to take a print. I came to find that the step was actually mating with the spindle bearing and preventing the part from seating. I can’t imagine this was intentional so I spent some time cutting this by hand to the point where the part contacted the bearing lightly when bolted up and contacting the mating surface well.
This resolved the issue and it checked square afterward.
This left one possible source of error, is the spindle centered in the chisel holder? For this I decided to install chisel, collet and auger and listen for misalignment. A misaligned setup will be very noisy. This one turns without squealing suggesting that everything is aligned within the clearance available.
Thank you for following along with this inspection and setup work.