My Lathe Project

[gbowne1]

Hello guys,

I'm in the process of designing a 9" x 48" Non-CNC lathe with DRO, for possible later conversion to CNC.

I'm just starting the planning and design process. Actually started last week.

Anyhow, Here's the details..

Motor: Single Phase, 110-120v AC, NEMA, 1/2 HP 1725 rpm. May also be
for 200-240v AC. TEHC or I/R?
Mfg.:Leeson or Reliable

Swing: 9" Bed length: 48"

Tail stock taper: #2 Morse Taper
Headstock taper: #3 Morse Taper

Spindle Type: Threaded, 1-1/2" - 8tpi

Tail stock travel: 2-1/8"
Cross Slide Travel: 5-7/8" (this dimenson not set in stone yet!)

Lead Screw: 1/2-10 ACME or 3/4"- 8 ACME (1/2" seems more common but is 3/4" better? Going to use "Rockford" Ballscrews.

Headstock bearings: ABEC 7 or 9 where available, undetermined size

Spindle Collet: 3C, 3J or 3AT (whichever is most common0

Spindle Through Hole: 3/4"

Spindle Lubricant: Hangsterfers Labs ISO VG grade
Way Lube: Hangsterfers Labs way lube
Cutting Fluid: ????

Spindle drive belt: Goodyear Industrial Power Transmission belts per their
"Variable Speed" .PDF @

http://www.goodyearindustrialproduct...able_speed.pdf

Lathe Bed & Ways: V and Flats.

Spindle speeds: ~40 to 1270 rpm (maybe more???)

Gear Supplier: Boston Gear

Spindle Bearings: TIMKEN, Inc.

Chuck: Cushman

Feed per Rev:
Longit.: 0.0015"to 0.0213"
Cross: 0.0004" to 0.0063"


Options: ER32 collet spindle nose chuck, Coolant Supply, Collets & Closer, 3 and/or 4 jaw Chuck, 2 Morse Taper Live & Dead Center, Steady & Follow Rests, Toolpost Grinder, Aloris AXA Q/C toolpost, DRO, Forward/Reverse & Emergency Stop, Taper attachment, Jacobs Ball Bearing drill chuck, threaded back plate, Face Plate, threading dial, micrometer carriage stop, power feeds(maybe a Q/C gearbox).

Ok, so this is the basic design specifications. I'll mostly be turning 12" lengths of 4140 and 4340 steel in 1-1/4" and 1-1/2' dia. and actually pretty regularly. Also, C1018, A36, Aluminum 6061 and 7075, brass, bronze, stainless, O1 & W1, Nylon 6/6 and PTFE.

May use a QC type gearbox or gearing based on a 40T stud gear.

I would love to hear your comments and suggestions.

Thank you for reading this thread,

Greg

[Stevie]

5C would be the most common; and can go to 1.125"
I just got a new set up to that in 1/16" steps; cost $180 cnd

I'll look up the Timkin when I get to work; my brg bible is there

edit edit
small lathe uses 32006X 30mm 55mm 20mm 9000 top speed
Big one uses 32009XA 45mm 75mm 20mm 6300 top speed

[gbowne1]

i've got the most common major sizes of 5c. I liked the smaller size collets because they only go to 1/2". I rarely collet up anything bigger than that anyhow.

Any other suggestions? part numbers if anyone has them would help me

Greg

[Stevie]

up to 5/8" I use ER25 for home use (just in my 4th axis)
at work we go to 1 1/8

ER grip well

[gbowne1]

I have, easily available to me ER16 and ER32 collets. But, I do have Centaur Precision ER32 in my shop that I use regularly. Most of the shops I worked at didn't have ER16, but had ER32 so I chose that type.

Anyhow, my latest choice is that I need to find a Gates IPT or Goodyear IPT V Belt that is 10mm wide x 37" long (may be able to use 36", 37.5" or 38"... not a critical dimension) The bottom of the V is 1/4"..

I've chosen 5 pulley steps.

I'm still learning AutoCAD 2005 so drawings would help immensely in this project. Anyone wanna do a drawing of the pulley for me?

Stevie, thanks for the information. You've been a lot of help so far.

Would it be better to use 1/2-10 ACME or 3/4-8 ACME? Which direction?????

Greg

[gbowne1]

I've decided on using NTN bearings, similar to 620xT1B7 or 620xT1P7 which are ABEC7 ISO P4. I have a small list of the ones that are in stock. I also h ave available to me, the 620xLLBP4/2A series bearings, both where x = a # between 2 & 9. I thought about 720x series also. 620x's are easier to get here in the NW. The TIMKEN info was a little sparse on what I wanted to find, unless someone can match me to TIMKEN #'s from NTN #'s.

I decided on a Gates 3VX375 belt going to a motor. This is a 3/8" x 37.5" long belt. I also bought a 3V375 as a spare.

I see that 3C is more common than the 3AT or 3J used in Atlas lathes. I may make the spindle with reference to that collet.

I still need to figure out if it would be better to use 3/4"-8 ACME or 1/2-10 ACME. Which one is more accurate, rolled or ground?

I need to be able to acheive crossfeeds of 0.0005" to .0056" and longitudinal feeds of 0.0021" to 0.0162", and will have powered feeds.

I thought of using a 16, 24 or 32 stud gear. And, 30t thrugh 60t for the other set, in 2's. The other setup I had envisioned was a 18t, 72t, 80t gear train and then adding the 16, 24 or 32 Stud gear and Screw gear set of 30t through 60t gears x 2t's. All being roughly 18-22dp. Boston Gear will provide a set at cost. Any ideas here?

I also have availabile to me some 8630 or 8640 steel, as well as stressproof 4340 which I will use to make the spindle @ finished to 5 microns RMS or ~.000005'", and a friend of mine who works at a spindle shop here in town said he could CNC me one for $180-$225, if I included the blueprint drawing and/or specs.

I need someone with a South Bend 9" model A lathe to measure the tool post slot T in their compound, as well as the thickness of it, at least if I get there, I can design the compound. I lost my lathe booklet so I also need the dimensions of the flats and V's on the carriage.

As for the ways on the bed, another local shop which does grinding on machinery ways, etc. offered to grind flats and V's on my stock, as well as the headstockusing either a blanchard or surface grinder..

I still need to hear back from several linear scale & dro manufacturers to find out which scales will work the best and how to best mount each one.

Anyone know of a blueprint for S/B carriage stops or threading dials?

Oh and I chose a Hangsterfers Labs way oil and their brand of Vactra spindle oil, maybe ISO 32 or 68?? Being supplied to the headstock using ordinary Home Depot sourced WATTS brand plumbing fittings. Coolant?? well, I'm being treated to a small supply of some of the best stuff made. Though I know it will be deilvered through a length of LOC-Line

Don't know what to do about a stand, bench, etc.. but I will provide for leveling on using those cool leveling pads they show in the catalogs.

Handwheels and dials are std. catalogue items, but ultra high precison quality.

How about a Dayton motor? Oh, and how about a E-Stop button?? Gotta think about safety. I really haven't looked that much into that type of machine controls. The ones I know about are OMRON or made for drill presses of various types.

Oh, and as for chucks. I really think the biggest I'll get to use would be 6", but I ran across some 1/2-20 threaded back 4" chucks a guy could use too. PProbably meant for 6" or 7" lathes but, they look to have decent precision & tolerances. When I set out the money for one, I'll likely buy a Cushman.

Anyhow thats it for now. Suggestions & comments welcome!

Greg

[pstockley]

Why not buy a used spindle cartridge or assembly (you'ed need to machine the bearing seats in your headstock)? There is one on eBay going for reasonable money

http://cgi.ebay.ca/ws/eBayISAPI.dll?...MEWA%3AIT&rd=1

[Mcgyver]

It would be good to hear your objectives and reasoning, otherwise we can spout off stuff from our experience but it may have no relevance. Ie, is this a bare bones money saving effort or to achieve some special functionality? I'm surprised no one's made the obligatory “I’d refurbish an old one comment…” comment, so I will: I'd start with an old lathe and rebuild. main reason is the inherent value of the castings and spindle. Regardless of objective, it would seem the best bang for the buck and depending on how fancy you wanted to go there’d be no shortage of challenging work.

Regardless, for a good general lathe, I’d change a few specs.... a larger bore through the spindle - its a pita and wastefull cutting off stock. use 5C's - smallest taper that works for them is M 4.5 (yes there is such a thing). 5c are also a lot cheaper and the 1", 3/4" etc get used a lot. Also, imo more swing is need and less distance between centres is required. the distance between centre distant is excessive – a lot of effort for that long bed – will it get used? I’d want a cam lock (or better still taper mount) spindle and 1200 is way to low, double it at least but triple would be better, especially if you are more inclined to do small dia stuff or want to use carbides.

Cool stuff to consider: go belt drive to a VFD – one day you could replicate the Hardinge system, you know where the speed changes on a facing cut to keep the same sfm. without going full cnc, you could use some electronics to your advantage, for example forget the QC, do it electronically via have an encoder on the spindle. Forget 5c/3c, go ER, better system but more $$$

[gbowne1]

Well..

I'm not really looking into buying an already built lathe, or refubishing an old one, and I epecially don't want chinese / import lathes.. I'm just a hobbyist, with a few design ideas. No, it's not a money saving idea, either. I just would like to be able to say something like "I've done it myself!" with this project.

As far as the spindle cartridge goes, well.. I don't really want to do that either. That's really way beyond my means, anyhow although it's a nice idea.

I really don't need a huge lathe, and the biggest dia. stuff I am going to be cutting is 1-1/2" (1.5000")

I may eventually go CNC with this lathe, and if not.. I may use a VFD in the future.

As for ER collets, I'm planning to use a collet chuck that I picked up.

For the motor, I definitley wanted to use at least 1/3 or 1/4hp.

Well..anyhow, I'm still working on my design.

[CNC Pro]

I just landed a monthly contract that required a “chucker” type lathe. The parts require simple end work, and there are a lot of them, a collet closer was a necessity.
After several weeks of looking for a reasonably priced used Hardinge (they don’t exist), I opted for building my own.
So I’ve started with a “import” 5C indexer. After extracting the inner workings (everything required for the 5C), I ordered (2)-45mm bore pillow block bearing assemblies, a pulley w/45mm sheave, and the required 5C collet, “BAM” one lathe spindle!
I then picked up a 20’ length of 6" wide * 3/16” thick “U”-channel, and as of last night, I’ve got the 28” long bed cut and the “head stock” mount. Some welding this afternoon should have everything solid. I have a ¾ hp motor for spindle drive and after a trial run, seems to run real smooth (and at 25+lbs for the spindle alone, it’s no wonder)! Total cost so far: $135.00
There is plenty of room for CNC additions, with plans to use Thompson type rails and linear bearings with ball screw drives. The 14” swing should give plenty of clearance for the cross slide. I hope to have photos soon.

[gbowne1]

Well, that's an interesting project. For my design, I'm not going to use pillow block bearings. I had even envisioned using automotive type front disc brake spindle wheel bearings of the appropiate size, but I've read that I should at least use ISO P4 ABEC 7 bearings.

I once had envisioned building a 13x40 size lathe with scrapped lathe components, but the cost would outrun my needs, and I had posted the details to rec.crafts.metalworking. Most of them had obliged themselves with the responce that I just go out and pick up a used 13x40, so I just thought to design and build my own 9x48 which is more size appropriate to what I need.

I do have the money to pick up a decent lathe, but I love designing things then seeing if I could possibly by any means nessesary make them myself, or with a little help. I love using off the shelf components in a lot of my work.

I'm in the middle of trying to draw up the plans for my headstock while I build it, using AutoCAD 2005. I also managed to get a start on machining the 1-1/2" x 8tpi tread which is roughly 7 to 9 threads long.

Well, that's it for now....

[gbowne1]

Please see my "my lathe project" posting in the Chaski www machinist boards

Greg