#hello #lathe #hello #lathe
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overclocked2300@...
Hello everyone
I am 34 and Im from CT. Ive been interested in gingery for sometime, but eventually I did buy a mini lathe and a mini mill, 7x16 and a G0704 from grizzly. They have both served me well. Recently, I came back to gingery as a long term project. I dont plan on doing aluminum casting, instead, I intend to use Epoxy granite as my bed. Ive got a rough skeleton laid out in fusion 360 and have a general idea. Ive also been practicing scraping, as I know I'll need to do that. I bought a 18x24 surface plate as well. I am also going to be scaling it up, or maybe doing custom. The bed itself will be 36"L, because you can get stock in that size. Swing wise, I am shooting for 12" diameter, or 6" rad. Its going to be close to a grizzly 12x24 lathe. I also plan on using an electronic lead screw, instead of gearing. I actually have a circuit designed (not tested) for that intended purpose. Main spindle motor will be a BLDC type, I actually have it in hand. Just have to build a controller for it :). So with all that said, I do have some questions: 1) Why did he use cold roll steel for the bed ways? Ive been throwing the idea around and some people have said that due to internal stress, you need to anneal it. Has anyone had an issue with using CRS? Im worried about wear. I tried finding places that sell cast iron...and I dont think they will sell single pieces. 1a) I found a place on the opposite side of the coast that sells O1 flat ground stock. I intend to use this as my ways. I havent decided if I am going to do a full 6"W bed or do a split bed like the Atlas 10 lathe. Id be worried that the carriage would pull up on the ways too much 2) I dont understand what parts were meant to be scraped. It seems that the Aluminum bed has to be scraped flat, but what was intended to be used as a reference? The CRS ways?
I do have photos of my build in fusion 360 to share as well so ya'll can get an idea.
-Chris |
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Bruce J
Dave used CRS because it’s flat and parallel from the vendor and is reasonably cheap. Yes, CRS is full of stresses from the rolling process; but those aren’t really evident unless you machine it. If you use it as is, it’s quite stable for this use. Cast iron stock is insanely expensive anymore because it’s just used a heck of a lot less.
That will be more accurate but normally that’s $$$$ compared to CRS; Dave’s process was all about building a machine shop for $ not $$$$ :-) I’d be much more inclined to use that O1 for making tools not bed-ways.
Yes. I’d have to dig my Gingery book out of the box it’s hiding in to get all the steps, but the ways are used as the primary reference surface for the entire lathe. -- Bruce Johnson "Wherever you go, there you are." B. Banzai, PhD |
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John Dammeyer
Look. If you are going to build your own larger lathe there are lots of ways to do this. There have been youtube videos on building a slant bed lathe. Look at how the high end systems now use the linear bearing races to build milling and slant bed systems.
If you decide to make something larger just go the linear bearing route mounted on something massive. This allows you to create two sets of tracks like the SouthBend and other lathes have with the tailstock on the narrower track inbetween the carriage track.
Do keep in mind the ratio of center height to carriage depth and width. That's why most of the larger lathes have two tracks. So that the carriage can be very wide relative to deep (square is bad) and still allow the tailstock to be moved close to the tool post.
There's that web site that lists all sorts of lathe and their specifications. http://www.lathes.co.uk/page21.html
Look at some of the better known lathes and work out their center height to carriage width and depth values and copy what already works. Don't start from the position that you know more than the designers over the last 100 years. As an example: http://www.lathes.co.uk/logan/index.html
There are groups for all the various older lathes like South Bend or Logan etc. Become a member and ask them for measurements if you can't find them on line. Go to your nearest tool store and measure what they sell.
John Dammeyer
From: gingery-machines@groups.io [mailto:gingery-machines@groups.io] On Behalf Of Bruce J
Sent: January-15-22 10:02 AM To: gingery-machines@groups.io Subject: Re: [gingery-machines] #hello #lathe
On Jan 15, 2022, at 7:40 AM, overclocked2300@... wrote:
Hello everyone So with all that said, I do have some questions: 1) Why did he use cold roll steel for the bed ways? Ive been throwing the idea around and some people have said that due to internal stress, you need to anneal it. Has anyone had an issue with using CRS? Im worried about wear. I tried finding places that sell cast iron...and I dont think they will sell single pieces.
Dave used CRS because it’s flat and parallel from the vendor and is reasonably cheap. Yes, CRS is full of stresses from the rolling process; but those aren’t really evident unless you machine it. If you use it as is, it’s quite stable for this use. Cast iron stock is insanely expensive anymore because it’s just used a heck of a lot less. 1a) I found a place on the opposite side of the coast that sells O1 flat ground stock. I intend to use this as my ways. I havent decided if I am going to do a full 6"W bed or do a split bed like the Atlas 10 lathe. Id be worried that the carriage would pull up on the ways too much
That will be more accurate but normally that’s $$$$ compared to CRS; Dave’s process was all about building a machine shop for $ not $$$$ :-) I’d be much more inclined to use that O1 for making tools not bed-ways. 2) I dont understand what parts were meant to be scraped. It seems that the Aluminum bed has to be scraped flat, but what was intended to be used as a reference? The CRS ways? Yes. I’d have to dig my Gingery book out of the box it’s hiding in to get all the steps, but the ways are used as the primary reference surface for the entire lathe.
-- Bruce Johnson
"Wherever you go, there you are." B. Banzai, PhD
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Bruce J
Hmm, I was wondering if those were robust enough for this use…I was looking at a small bench top mill build using those.
Although I’ve got about 10’ of 40x40 extrusion I was going to use for the main frame for better rigidity, and maybe a different spindle instead of a router. (another reason to dig out my Gingery omnibus book; to look at the Drill press build as an example of a quill design) I guess of the ‘big guys’ are using them … it should work!
-- Bruce Johnson "Wherever you go, there you are." B. Banzai, PhD |
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overclocked2300@...
So actually, someone made a 1:1 scale model of the Atlas 10, so thats my base. I may do the ways like gingery did (one full sheet) or separate. I was going to do separate ways and then align them, but that was before I had joined this group. It seems that CRS is still on the table. Ive been using the Atlas 10 model and doing measurements and then basing my skeleton frame off of that. Linear Rails: I have seen that done on YT as well. But, I wanted to try to keep things locally sourced..and to keep within certain constraints, I didnt want to order from Aliexpress. I also dont know how accurate their specs actually are, but then again, you dont know how accurate American specs are either. I still like to think the linear track idea is on the table, but, I worry that they wont be able to handle the loads of a lathe during cutting. There is still something about making box ways and then scraping them all in. I think the making aspect is what excites me. Dont forget, I have a much better head start. Surface plate, lathe and mill are all in good order. Ive actually been using my lathe to make tools for itself, first one was a steady rest, and now I need a face plate. Next up is a lathe dog. I'll need these to turn centers to make a spindle. |
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Wouldn't drilling the holes be a form of machining? Has anyone in the group ever experienced warping or creepage from using CRS? I did see someone had a wear issue that looked quite minor. I also did look at using high carbon knife steels (equivalent to 1080) since I knew these were annealed. Other than O1 steel, what would be better than Cold rolled 1018? I looked into 4140 The advantage of using CRS is that I can pick it up locally and not pay shipping-which is nice.
Edit: Id also like to add that I planned on using 3/8" thick O1. If CRS will do, I'll bump it right up to 1/2" for more rigidity. |
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overclocked2300@...
Looking locally, a 6"W x 1/2" thick x 36"L piece of CRS is $160. For ~$20 more I can get precision ground O1 stock, however, it would be at 3/8" thickness and not 1/2".
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