@WillAdams suggested a whole machine simulator. I heartily agree. Especially for someone with little machining background, the visualization can be very helpful in understanding the process.
I suggested a G-code simulator in my list. That may be a bit too abstract for some. Seeing “the whole thing” in motion can speed learning.
Whole machine simulators are very important when there are complex fixturing (stock holding) situations. The last thing one wants to do is have a collision with a fixture - be it a Nomad, an SO3, a Tormach, a $US150K Haas, or a $US250K Datron.
Fusion 360 - an excellent CAD/CAM package (with a bit of steep learning curve (but well worth it) - has excellent simulation abilities. High end CAM packages - $$$$ (e.g. BobCAD-CAM, MasterCAM, SprutCAM) - all have excellent whole machine simulators.
So… anyone know how to get those slip-fit pins out of the original bed?
I appear to have one of the 883’s that had extra tight fastening and Loctite holding the bed to the Y-axis runner. I managed to break all 6 bolts loose without stripping them, but the two dowel pins are practically set in concrete. I’m probably missing the correct tools for the job, but even a few minutes of judicious hammering didn’t even budge one of them.
These dowels are rather different from the industrial ones I’m used to seeing – they’re solid, and “domed” on each end, so there’s no way to use a normal dowel-pulling tool. Each end has a small, off-center “crater” in the dome, but it’s not so pronounced that I feel comfortable sticking a small-diameter tool into the crater and getting my hammertime on. Especially since “mushrooming” these dowels would be really self-defeating…
So, is there a special trick to this, or just a matter of rolling the dice and using a bigger hammer?
@SkyeFire, since the bed is aluminum and the pins are steel, and since aluminum has a larger coefficient of thermal expansion, I’d suggest reasonable heat–ovenish rather than foundryish–that will both differentially expand the bed just slightly, and also degrade any Loctite that wicked in. You should be able to pull (or drive out) the pins reasonably easily while the bed is hot.
Ran out of time to try it, but I’ve got a big heat gun (think hair dryer on steroids) that might just do the trick. Have to find a way to use it without melting parts of the Nomad, though.
Do the dowels have to be hammered out from top or bottom? They seem pretty symmetrical, vertically.
I wonder if I could (should?) replaced the current dowels with some threaded-interior industrial dowels of the same size (assuming I can find any)? That would make them easier to remove with a dowel puller if I ever have to do this again.
I just replaced my bed. I used a heat gun that I had. It didn’t take more than 10 minutes - moving back and forth between and around the two pins - for the bed to pop off without much difficulty.
The bed didn’t really get THAT hot. I was conscious of everything underneath but didn’t see any other way to get it off without doing a gorilla on it.
I put the new bed on the old pins - fit fine as I did it quickly - and everything it nice and tight now.
@SkyeFire, oh! I thought the bed was already out of your machine and you just wanted to reuse the pins! @mbellon is braver than I would be since the Y-axis linear bearings are right near where the bed attaches to the carriage. Mark’s gradual heating is definitely the way to go.
All I wanted to do was pull the bed and replace it. I didn’t want to pull/push on it too much - initially it seemed a bit hard to move - so I heated the bed a bit and it came off easily. The pins stayed well held to the undercarriage.
The bed didn’t get very hot, but the temperature differential made it easier to remove and replace. The bed was not too hot to touch, the undercarriage was warm. The heat gun was on the lowest setting and I was careful to apply the heat evenly and from a distance from the bed. Gently, ever so gently. When I felt the bed move, I cut the heat, popped and replaced the bed, and got two screws on the the longest diagonal in - but not too tight. The rest of the screws went in without difficulty. Then I torqued all the screws.
I avoided letting the heat hit the pins directly. I was more interested in heating the bed.
Well, some heat&beat did the trick. The trickiest part of putting the new bed in was not knocking off the little washers while getting the bed situated, but I eventually pulled it off:
The cams that came with my sea-of-holes bed are nice, but I’d like to get the clamps that were mentioned upthread. But I can’t find them on High Tech’s web page under the Workholding tab. Am I just looking in the wrong place, or are those clamps not available yet?
A) Is 0.500" tall. It includes a sea-of-holes AND all of the holes for the vise and flip jig.
Available Z will be 0.250" than standard bed.
B) The sea-of-holes uses Imperial screws (10-32 as I recall).
C) There are some CAMs available but the rocker clamps are yet to appear.
D) Requires replacement of the existing bed. Not very hard.
E) More holes than the C3D.
F) Less expensive than the C3D one (US$70).
G) Not anodized.
H) Regular sea-of-holes pattern - advantages and disadvantages.
0.500" on center
I) Not the official product.
The C3D:
A) Is 0.7500" tall when it is attached.
Available Z will be 0.500" than standard bed.
B) The sea-of-holes uses Metric screws (M6 as I recall).
C) No CAMs or clamps are available at the time I write this. C3D says they will have goodies.
D) Screws down over the existing bed - not a replacement; easy on/off.
E) More available Z (0.250") for the flip jib and clamp - remove the sea-of-holes plate.
F) More expensive than the HighTechSystems one (US$100).
G) Anodized.
H) Inner and outer sea-of-holes pattern differ - advantages and disadvantages.
If you can put a wasteboard over the High Tech one then yes. We use the same 4 mounting holes in the corner of the table for the new threaded table and the wasteboard.
