Liquid Sun
Plastic
- Joined
- Jul 23, 2020
Hi all,
I'm looking into getting some tools for rebuilding my Maho MH600E. It has two box ways on X and Z (as a vertical mill), and a dovetail way the Y axis. Going by what's written in the Connelly book, I should get a surface plate that covers the length of the longest ways (which is about a 120 by 80 cm surface plate in a standard ISO size), plus a straight edge with a 45 degree angle on it that's about 120 cm.
I don't have any spotting tools, so I thought the easiest thing to do would be to buy a new high-grade granite surface plate to have a known flat plane. I could then get a used straight edge in good length or have one cast at a foundry, since I'd have a known reference plane for scraping. But, unlike cast iron surface plates, granite ones don't come with handles and aren't ribbed for additional stiffness. And I still want to use the surface plate for reverse spotting the ways on the machine casting. If it was just for measuring, I'd get a much smaller one.
This bugged me, so I emailed the local manufacturer of granite plates here, and he replied that they don't drill holes in their products (e.g. to put in threaded inserts and screw on a pair of handles), and that their plates will bend if unsupported correctly on a three-point stand. To be clear, the size I'm after would be 120 mm thick diabase from what he's selling.
In the application I considered for using the surface plate, it would be hung from a winch over the casting for reverse spotting for a lot of the work, which needs some kind of handles for chains or straps, and shouldn't result in ruining the flat plane. So, are grainte surface plates used for reverse spotting at all? Am I looking to buy one as a master surface and then getting a cast-iron surface plate that I'm going to be using for reverse spotting? Or should I rely on a grinding job (for which there is an excellent venue near me) to fix my alignments and only scrape in some oil pockets?
I get that you can spot along the length of the ways with a straight edge and use a small, hand-held surface plate to spot across the ways. But it seems like it increases the chances of error and makes for a lot of additional spotting. For what it's worth, I fully intend to get the spindle inner tapers (vertical and horizontal) ground anyway, and possibly even have some parts reduced in thickness to glue in turcite, so it's not like I want to do everything myself at all costs and pay a maximum price of a bag of peanuts for tools stolen from the scrapyard for the rebuild to be economically viable.
One of the chief reasons I'm leaning towards working on this myself is that most rebuilders I talked to will actually tear down the machine and replace damaged parts, but they still have the ways and sliding members ground by an outside company before rebuilding. That just doesn't seem to be worth the back-and-forth driving and fitting my needs into their schedules. Around these parts, most rebuilders actually specialize in electronics, servos and controls, some basic mechanics, but not real alignments. One of them outright told me it's not worth it and that I should get a different used machine if I'm not happy with the one I got. I agree on principle, but I already replaced the control on my mill (with LinuxCNC, hi how are you), and the only reason I want to do a rebuild is because I'm sitting on designs for two injection molds that have features located to within a tolerance of 8 microns. It seems a bit futile to drive around Europe looking for a bargain bin machine that will make those sorts of parts.
Sorry for the long post, I wanted to be clear about where I'm coming from with this project. I'd be very thankful for any useful input, and if you want to just tear me a new one, I don't really mind either. I got pretty thick skin from hanging around my inlaws on holidays
I'm looking into getting some tools for rebuilding my Maho MH600E. It has two box ways on X and Z (as a vertical mill), and a dovetail way the Y axis. Going by what's written in the Connelly book, I should get a surface plate that covers the length of the longest ways (which is about a 120 by 80 cm surface plate in a standard ISO size), plus a straight edge with a 45 degree angle on it that's about 120 cm.
I don't have any spotting tools, so I thought the easiest thing to do would be to buy a new high-grade granite surface plate to have a known flat plane. I could then get a used straight edge in good length or have one cast at a foundry, since I'd have a known reference plane for scraping. But, unlike cast iron surface plates, granite ones don't come with handles and aren't ribbed for additional stiffness. And I still want to use the surface plate for reverse spotting the ways on the machine casting. If it was just for measuring, I'd get a much smaller one.
This bugged me, so I emailed the local manufacturer of granite plates here, and he replied that they don't drill holes in their products (e.g. to put in threaded inserts and screw on a pair of handles), and that their plates will bend if unsupported correctly on a three-point stand. To be clear, the size I'm after would be 120 mm thick diabase from what he's selling.
In the application I considered for using the surface plate, it would be hung from a winch over the casting for reverse spotting for a lot of the work, which needs some kind of handles for chains or straps, and shouldn't result in ruining the flat plane. So, are grainte surface plates used for reverse spotting at all? Am I looking to buy one as a master surface and then getting a cast-iron surface plate that I'm going to be using for reverse spotting? Or should I rely on a grinding job (for which there is an excellent venue near me) to fix my alignments and only scrape in some oil pockets?
I get that you can spot along the length of the ways with a straight edge and use a small, hand-held surface plate to spot across the ways. But it seems like it increases the chances of error and makes for a lot of additional spotting. For what it's worth, I fully intend to get the spindle inner tapers (vertical and horizontal) ground anyway, and possibly even have some parts reduced in thickness to glue in turcite, so it's not like I want to do everything myself at all costs and pay a maximum price of a bag of peanuts for tools stolen from the scrapyard for the rebuild to be economically viable.
One of the chief reasons I'm leaning towards working on this myself is that most rebuilders I talked to will actually tear down the machine and replace damaged parts, but they still have the ways and sliding members ground by an outside company before rebuilding. That just doesn't seem to be worth the back-and-forth driving and fitting my needs into their schedules. Around these parts, most rebuilders actually specialize in electronics, servos and controls, some basic mechanics, but not real alignments. One of them outright told me it's not worth it and that I should get a different used machine if I'm not happy with the one I got. I agree on principle, but I already replaced the control on my mill (with LinuxCNC, hi how are you), and the only reason I want to do a rebuild is because I'm sitting on designs for two injection molds that have features located to within a tolerance of 8 microns. It seems a bit futile to drive around Europe looking for a bargain bin machine that will make those sorts of parts.
Sorry for the long post, I wanted to be clear about where I'm coming from with this project. I'd be very thankful for any useful input, and if you want to just tear me a new one, I don't really mind either. I got pretty thick skin from hanging around my inlaws on holidays