So I recently surfaced work’s S5 Pro’s waste board and it came out rather lumpy. Figured it was time to actually tram the spindle. Now that I am doing this for work I actually have a small budget for tooling. I figured I would splurge and get proper tramming jig. I quickly settled on this guy:
Reviews were decent and it provided the level of accuracy that is achievable with the S5 Pro. I also picked up a sheet of this “Dead Flat” floated glass that I saw recommended on here somewhere:
to act as a reference surface. I followed a YouTube tutorial on how to use the SST Tramming System. It had me level the four corners of the glass, zero both indicators to the same reference spot, and finally start taking measurements.
My spindle was all sorts of out of tram! Far more than I initially thought. I tried and tried to get it trammed in but nothing I did seemed to get it where it needed to be. After pulling my hair out for half a day my colleague asked an important question, “How do you know your glass is flat?” When I did the initial setup I had checked that the glass was flat to within about 0.002" but I only did so in in one direction. In the other direction the glass dips down by over 0.04" in the middle. The damn thing is banana shaped. Guess it is time to get a surface plate :-/
Yeah I am returning mine and ordered a 6" x 6" Grade B surface plate. Supposed to be flat to within 0.0001". We’ll see when it gets here. I am just pissed that they did no quality control on their ‘Dead Flat’ piece of glass.
Usually when most people don’t have instruments to measure as small as 0.0001, companies that sell equipment that is either supposed to measure or be measured at tolerances this small can’t always guaranty that these things are properly tolerance. It would be so much for them to make such equipment at such a tight tolerance, that if they actually could cut these tolerances, then the prices of these pieces of equipment would be on the higher side. I’m not saying that its not possible, I know these tolerance are hard to hold without highly precise and repeatable equipment. I know because I used to hold things in such close tolerances.
Now just imagine these tolerances as in comparison to a human hair thickness. A standard human hair is 0.010 thick. Now imagine taking that hair and cutting it long ways 10 times equally, and now you would have strips that are 0.001 thick. Now take one of those strips and cut it long ways the same way as before. That would give us 10 more equal strips now that are 0.0001 thick each. That is how tight that tolerance is. So, if a person was working on surfacing something and just so happen to drop a single human hair under one side of the surfacing being done, it would be out of tolerance by 0.01 right off the bat. I know you might know this, but I am saying this so many others would know.
I found it best to just go ahead and mill out an area big enough for the tramming tool using a 1/8" or 1/4" endmill with a small stepover. I bolt down a square piece of MDF and flatten that to use once bolted down. That makes a flat and leveled area that is WAYYYYYYYYYYYYYYYYYYYYYYYYYY easier than trying to shim a piece of glass flat and level. Seriously, trying to get a “flat” piece of glass perfectly leveled is an exercise in wasting time. With how wide tramming tools are (intentionally) a few thou of being off level means that even a 1" surfacing bit is well trammed for the precision CNC routers are generally capable of.
What @SLCJedi says is totally true. However, if you are also using this as an opportunity to learn more about precision and flatness, there is nothing wrong with chasing small numbers. Taking my machine farther than is reasonable for a CNC router is a big part of how I learned what I know about precision measurement.
I have the SST and also bought that useless glass.
Luckily I also had a granite slab that was machined to be flat with high precision. My brother used it as a flat surface for sharpening chisels. Same purpose that glass is supposed to be for I guess.
I have no issue with chasing zeroes… I’m really prone to it myself. But I’d rather get closer to zero than fiddle around even getting the method to work.
A glass mirror was good for me. One can immediately see whether that thing shows any irregularities. Unfortunately the best mirror was the one in the bathroom. She was little upset.
I ended up using an offcut of kitchen worktop I had lying around as it was flat enough for my purposes and a consistent thickness. The tramming is close enough for the woodwork I’m doing though I’d likely dial it in more for metal.
As an extra piece of info I learned, surfacing wood across the grain shows tramming marks/lines way more than surfacing in the same direction as the grain.
I was tramming, surfacing the wood, tramming, surfacing the wood and continuing to see little lines. As it happens, it was fairly well trammed and it was just because I was cutting across the grain.
As soon as I cut along the grain, it was super smooth and I couldn’t see any lines.
I am not about to go chasing Zeros. I am well aware that at some point the S5 Pro is going to be the limiting factor. I also know that you can get pieces of glass that are more than flat enough for my purposes. 0.002" is more than flat enough for me.
What has me pissed off the most is that that same piece of glass comes up when searching for “Surface Plate” in Amazon which means that they have some how put it in the same category as Surface Plates. Couple that with the “Dead Flat” in the name and it made me think that this piece of glass would do the job. Instead I get a banana that my dial indicators jump around by close to half a rotation. Admittedly this piece of glass is meant for knife sharpening, but don’t advertise it with Surface Plates if you cannot even get remotely close to that level of flatness. 0.04" is a joke.
