I wonder if this is the right forum section to post to if i' m wrong direct me to the right one
I' m trying to build machines from the gingery books series (i' m starting with the lathe ofc) and i' m having some difficulties. I tried to post at gingery machines yahoo group but haven' t received any response so far so i hope i will be of better luck here.
Ok, here's the original post to gingery machines group:
I live in Croatia and i envy you guys for the selection of materials you can get in your countries because i have a hard time finding suitable materials to build the lathe.
I basically have to make everything from substitutes and as makeshifts which i really don't like because i would like to build everything as good as it can be built.
I have managed to get a good quality refractory cement (wasn't easy) so my furnace is built to spec and is going to last a long time.
Surprisingly it is easier to get tool steel here than cold rolled steel, well in acceptable thicknesses anyway. Best cold rolled that i could find was 2-3mm thick, and until i found a company that sells tool steel i was considering using plain hot rolled steel for lathe ways which would probably be a very bad material choice.
Anyway now i have a problem deciding which steel grade would be the best for the ways and i was wondering if someone here can help me decide.
My concerns are:
1. the ways wont slide and lubricate as they should (which grade is the best bearing material?)
2. i won't be able to scrape (or even cut) the ways with the tools that i have (I don't know if i will even need to scrape those bars,
i reckon they are finished to a better standard than plain cold rolled steel, or am i wrong and the only difference is the material composition?)
3. the price (I still don't know the price for the bars because i need to call the company to find out the prices and i need to decide on the grade first. I also don't know if i will have to purchase the whole length of the bar as i would have with hot rolled so this is a big concern. If someone could post some prices at which tool steel of same grades and thicknesses is available in your countries i would appreciate it.)
If you have the time to check it out here is the link to the company's website. It is in croatian but the catalog is pretty easy to understand (it' s a 32.3 MB PDF file) - click on that book picture in the upper right corner to download it (below the text "PREUZMITE KATALOG"): Strojopromet-Zagreb
Tool steel (it's called "Alatni celik" in croatian) in bars is on page 77. I plan to improve on the gingery lathe design so i will probably go with these sizes for lathe ways and upscale the whole design as needed (that still depends on point 3 in my concerns list, maybe i will need to follow the book to keep the price in check):
1.5cm (2cm) X 8cm X 10cm compound swiwel slide ways
1.5cm (2cm) X 12cm X 18cm cross slide ways (carriage)
2cm X 15cm (20cm) X 1200+cm bed ways
apron 15 cm
As you can see i plan to increase distance between centers (my threaded bar is M20x100 ) and swing over bed and carriage. I would rather use thinner bars as i think 1.5 and 2 cm is an overkill but as you can see - that thickness is all they can offer at that width.
Back to concerns number 1 and 2. Steel grades in the catalog are stated as old local standard and as CEN (European standard steel grades). I have found this site with steel specifications so you can quickly determine which one is the best (it also has grade designations in different standards - AISI, DIN):
If i can't get the bars cut to size i am planning to cut them with my angle grinder. I have cutting discs designated to cut INOX so i think that will work.
I plan to make scraping tools from used taps made from HSSE so here's
HSSE stats for comparison:
I hope i can find someone here whose profession requires knowledge about matters stated in my questions/concerns so i won't be left to my judgment which would basically be guesstimating and hoping for the best, lol. Anyway, thanks in advance for any input and response i appreciate it.
Btw, i strive to improve my english so if u notice any errors in my text please correct me.
Yes, as tool steel is out of my reach at the moment (i have spent money on some measuring equipment) i will use HRS instead. I discussed that option on another forum/bbs and that was the recommended option. CRS was used in the gingery book because it was already pretty flat.
Some doubts still remain regarding HRS (its suitability for extreme precision parts, regarding internal stress and heat treatment) but i am confident now that it will be good enough, at least for the starting build (maybe even better than CRS) and probably also as a long run solution. Downside is that it will require much more scraping to make it flat and it also has mill scale on the surface that needs to be taken off before the scraping begins.
I found and bought some nice, thick and relatively flat HRS bars that i will use for the lathe and some other projects when i finish with this one.
thank you for your support; I know that HRS is a pain to scrap, I did the main lathe ways yesterday out of HRS and man, my hands hurt :-D
and even though I have precision instruments, I still couldn't get it perfect; maybe my HRS's quality isn't satisfactory, and believe me I've worked/scraped for about 6 hours and there's still alot to improve
Good luck to you too with your projects
about this - did you remove the scale before you started scraping as i have advised?
It is important to remove that because it is much harder than the metal that is underneath it, and it will eventually (if exposed to elements) start to deteriorate so it is essential that you remove it (don't use a grinder or anything like that use acid (diluted)).
The real metal that is underneath it will be much easier to scrape (although it will take some time to flatten the bar as it is not as flat as CRS). Keep at it. ;D
> and even though I have precision instruments,
> I still couldn't get it perfect;
You should compare it to a surface plate if you have one. If not use the three plates method - google it up.
Hello, I admire your tenacity to go ahead with the Gingery build lathe with HRS and I have built the lathe, the milling machine and the shaper but here in the USA cold rolled steel is readily available. I would think that scrapping will be very time consuming but it can be done, and wonder if you might perhaps think through finding an alternative method like using the HRS for a base metal and perhaps adding a tool steel plate to it for the actual surface the carriage will ride on? How far have you got with this build and can you post an update here? If I can be of any help I will be glad to try since I have built all 3 machines and even did the Gingery leaf brake as well.
Regards,
Wes
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Gingery lathe build - ways material choice
) and swing over bed and carriage. I would rather use thinner bars as i think 1.5 and 2 cm is an overkill but as you can see - that thickness is all they can offer at that width.
