- Joined
- Nov 7, 2019
- Messages
- 433
A bit of a sidetrack from my workshop thread (Workshop).
Work surfaces has been an ongoing struggle in my garage, the first table was too weak, the second too large and space inefficient.
So this is my third try...
I found these two cast iron plates on the Swedish equivalent of craigslist and decided they'd be a good start for it.
They're both 400x800 millimeter in width and length but one is 140mm thick and the other is closer to 105.
Neither is completely solid, underneath they have a hollow part, the thicker with some webbing like most cast iron surface plates have.
I calculated that the thick one weighs in at around 222kg so it's a difficult piece work with.
Since both plates have been beaten up quite severely I wanted to try and deck them in my mill.
My mill has a movement of around 230Y and 630X on a good day so I'm going to need do this in several setups.
But first to even get it up on the mill I had to experiment with the engine hoist.. The thicker one already had some bolt holes in the side I could wrap the sling around.
The sheet itself is bigger than the saddle casting..
Just the weight is causing quite a lot of issues for my non-perfect CNC conversion.
The Z motor keeps stalling from the combination of a sticky Z axis and the added weight and the Y axis gets serious problems moving when all the weight is cantilevered out to the left.
This makes it difficult to do fine adjustments or efficient movement patterns since I have to manually(with a plier) help the Z stepper motor to set my depth and can only (reliably) move Y when the weight is somewhat centered on the saddle.
At least it's giving me a lot of notes on what to improve upon.
The milled surface is pretty much the full movement of the previous setup, I've now moved it as far left as possible so I can reach the other side of the plate.
It's so far to the side that I can't use any T-slots and have to resort to carefully clamping around the entire table, with a wooden piece inbetween to not damage the ways.
So far I've only been using a 40mm corncob style endmill.
This is what the surface finish is like with the endmill.
Tramming was a tiny bit out in the X rotation axis whilst side to side tram was great.
You could just about feel an edge between the old and new cut, it's probably slightly below 0.1mm.
Cutting it this way took a lot of time since I didn't have the guts to speed up the mill very fast from fear of unneccessarily dulling it.
For those of you that are into 'memes', this really made me think of "you versus the guy she told you not to worry about".
Kinda hidden in the background, I've drilled and tapped 5 holes in the center pocket, this will aid both lifting the plate and fixturing parts on it later.
Many hours later, thick plate has been decked. I did a couple of mistakes and I think the entire plate is probably only within 0.2-0.3mm but was so tired of it that I decided it was good enough for now.
I still need to remove a bunch from the bottom to make it equal thickness to the other one, which might cause the plate to shift a bit so will most likely redeck it again.
Had I been smart I would've started with the small plate but I learnt a ton on the big one so maybe it was good after all.
Swapping out the large plate to the small plate, I first flattened the bottom and then started flycutting top.
I was super picky here and removed maybe 0.2mm at a time, each time adjusting my tramming a miniscule amount until I got the cuts to blend perfectly into eachother, EXTREMELY time consuming.
Of course I crashed the mill, ruining my tramming, maybe an hour after it was perfect.
At least the flycutter is giving a better finish, takes around the same time as the endmill since my feed is much slower but the width is much larger.
You can see the head and tool in the reflection of the plate, something that definitely wasn't possible on the other plate.
I found that I have to go up quite a bit in surface speed, above 120m/min to get a good surface, but this is also very close to making sparks so I save it for the fininshing cut and spin slower for roughing to not dull the tool.
It's interesting with heavy things like this because even just flipping them over is a difficult task.
I drilled and tapped for M12 bolts in the sides of both plates and made an improv lift bar.
It's too short for turning it midair(chains get caught) but at least it made it a ton easier to lift it slightly from the floor and carefully start leaning it over.
This is definitely one of those jobs where "slow and steady wins the race".
Rather make a tool that makes the job easier, than try to do it fast and dangeorus(ie manhandling it over which I tried on the smaller one).
Finally on the mill with the bottom up, I gave my 25mm insert endmill a try for roughing.
I need to remove nearly 4cm of cast iron, each edge being 5cm wide and I definitely didn't feel like wearing down my regular endmills for this when inserts for this insert endmill are dirt cheap on ebay.
To my suprise it also loves high feeds and speeds.
From ~200rpm and 150mm/min with the 40mm endmill @1mm doc I could go up to 1088rpm and 500mm/min @ 2mm doc, just seeing the spray of cast iron chips was pretty fun and it left a superior surface as well.
Even at these speeds it takes quite a while and the stepper motors still stall out from time to time, leading me to have to reset the control software etc.
I'm going to scrape the machine in, change to ballscrews, gear the steppers even stronger and build in a better oiling system in the future so hopefully this won't be a problem after that.
But for now it's a half-manual process where I set the Z by hand and then let it run a short program that mills the shown surface before I move the plate on the table.
Hopefully I can finish these plates up soon and move on to the actual table build!
Work surfaces has been an ongoing struggle in my garage, the first table was too weak, the second too large and space inefficient.
So this is my third try...
I found these two cast iron plates on the Swedish equivalent of craigslist and decided they'd be a good start for it.
They're both 400x800 millimeter in width and length but one is 140mm thick and the other is closer to 105.
Neither is completely solid, underneath they have a hollow part, the thicker with some webbing like most cast iron surface plates have.
I calculated that the thick one weighs in at around 222kg so it's a difficult piece work with.
Since both plates have been beaten up quite severely I wanted to try and deck them in my mill.
My mill has a movement of around 230Y and 630X on a good day so I'm going to need do this in several setups.
But first to even get it up on the mill I had to experiment with the engine hoist.. The thicker one already had some bolt holes in the side I could wrap the sling around.
The sheet itself is bigger than the saddle casting..
Just the weight is causing quite a lot of issues for my non-perfect CNC conversion.
The Z motor keeps stalling from the combination of a sticky Z axis and the added weight and the Y axis gets serious problems moving when all the weight is cantilevered out to the left.
This makes it difficult to do fine adjustments or efficient movement patterns since I have to manually(with a plier) help the Z stepper motor to set my depth and can only (reliably) move Y when the weight is somewhat centered on the saddle.
At least it's giving me a lot of notes on what to improve upon.
The milled surface is pretty much the full movement of the previous setup, I've now moved it as far left as possible so I can reach the other side of the plate.
It's so far to the side that I can't use any T-slots and have to resort to carefully clamping around the entire table, with a wooden piece inbetween to not damage the ways.
So far I've only been using a 40mm corncob style endmill.
This is what the surface finish is like with the endmill.
Tramming was a tiny bit out in the X rotation axis whilst side to side tram was great.
You could just about feel an edge between the old and new cut, it's probably slightly below 0.1mm.
Cutting it this way took a lot of time since I didn't have the guts to speed up the mill very fast from fear of unneccessarily dulling it.
For those of you that are into 'memes', this really made me think of "you versus the guy she told you not to worry about".
Kinda hidden in the background, I've drilled and tapped 5 holes in the center pocket, this will aid both lifting the plate and fixturing parts on it later.
Many hours later, thick plate has been decked. I did a couple of mistakes and I think the entire plate is probably only within 0.2-0.3mm but was so tired of it that I decided it was good enough for now.
I still need to remove a bunch from the bottom to make it equal thickness to the other one, which might cause the plate to shift a bit so will most likely redeck it again.
Had I been smart I would've started with the small plate but I learnt a ton on the big one so maybe it was good after all.
Swapping out the large plate to the small plate, I first flattened the bottom and then started flycutting top.
I was super picky here and removed maybe 0.2mm at a time, each time adjusting my tramming a miniscule amount until I got the cuts to blend perfectly into eachother, EXTREMELY time consuming.
Of course I crashed the mill, ruining my tramming, maybe an hour after it was perfect.
At least the flycutter is giving a better finish, takes around the same time as the endmill since my feed is much slower but the width is much larger.
You can see the head and tool in the reflection of the plate, something that definitely wasn't possible on the other plate.
I found that I have to go up quite a bit in surface speed, above 120m/min to get a good surface, but this is also very close to making sparks so I save it for the fininshing cut and spin slower for roughing to not dull the tool.
It's interesting with heavy things like this because even just flipping them over is a difficult task.
I drilled and tapped for M12 bolts in the sides of both plates and made an improv lift bar.
It's too short for turning it midair(chains get caught) but at least it made it a ton easier to lift it slightly from the floor and carefully start leaning it over.
This is definitely one of those jobs where "slow and steady wins the race".
Rather make a tool that makes the job easier, than try to do it fast and dangeorus(ie manhandling it over which I tried on the smaller one).
Finally on the mill with the bottom up, I gave my 25mm insert endmill a try for roughing.
I need to remove nearly 4cm of cast iron, each edge being 5cm wide and I definitely didn't feel like wearing down my regular endmills for this when inserts for this insert endmill are dirt cheap on ebay.
To my suprise it also loves high feeds and speeds.
From ~200rpm and 150mm/min with the 40mm endmill @1mm doc I could go up to 1088rpm and 500mm/min @ 2mm doc, just seeing the spray of cast iron chips was pretty fun and it left a superior surface as well.
Even at these speeds it takes quite a while and the stepper motors still stall out from time to time, leading me to have to reset the control software etc.
I'm going to scrape the machine in, change to ballscrews, gear the steppers even stronger and build in a better oiling system in the future so hopefully this won't be a problem after that.
But for now it's a half-manual process where I set the Z by hand and then let it run a short program that mills the shown surface before I move the plate on the table.
Hopefully I can finish these plates up soon and move on to the actual table build!