[Verell]

Google coughed up this link to SIEG's own version of the C4 manual. Suspect the other manuals were derived from this one as the pictures seem clearer & the drawings crisper:

http://bbs.51sieg.com/upload/C4%E8%8...E%E4%B9%A6.pdf

Altho more complete than the Travers manual, It doesn't have the change gear & some other info that the Axminster manual has.

[topknot]

I did have a chance to run one up at a showroom for a couple of minutes. The motor seems well braked and stops quite quickly when you press the stop button. Whether that would be quick enough I wouldn't like to say. The only lathe in this size range (that you commonly see) which has a clutch is the Myford.

When simply turning using the leadscrew feed, aren't the half-nuts quick enough to prevent running into the shoulder/chuck? Granted screwcutting is a more fraught proposition but thousands of users seem to manage without a clutch and without being able to disengage the half-nuts when screwcutting.

Even on my Myford with its clutch and extra low speed backgear, I use a handle to manually turn the spindle when I have to cut a thread very close to a shoulder.

[Verell]

The motor stops pretty quickly, but I think the half-nut lever is quicker.

...When simply turning using the leadscrew feed, aren't the half-nuts quick enough to prevent running into the shoulder/chuck? ...

You'd think so, but I've got a bad case of distractability. With my 7x12 I found that it's very easy to be looking the wrong way at the wrong time. After several ruined pieces & broken carbide tips, I decided to cut towards the tailstock whenever possible. A side benefit is that I can start every cut right at the shoulder & almost never have to cleanup the shoulder.

...I use a handle to manually turn the spindle when I have to cut a thread very close to a shoulder.

I generally just use the chuck itself as a handle & cut the final 1-2 threads by hand..

One thing I've already discovered is that I'm going to miss the really slow speeds I could get out of the mini-lathe's variable speed control for precise work. With the reduced torque at slow speeds, I could easily tap M4 & M5 holes with the lathe, stopping & reversing the chuck when the tap started to bind.
The C4's minimum speed is 100RPM, a tad too fast for my ageing reflexes on realy close work. It also has A LOT of torque at 100rpm. Don't think I could stoop the chuck with my hands.

[JHanko]

Verell,
Thanks for the second link to an owners manual. It's even better than the first, worthy of a printout. I never completely read the manual before because of the crappy quality, but this one is so nice I decided to read through it completely. One very funny thing I noticed was this line in the "Operation" section: "Do not carry the tool by its power cord". Ha, I would love to see someone try that...

Jeff

[JHanko]

Just wanted to add one more thing. Here's an example of how much low speed torque this thing has. Lately, I have been drilling quite a bit of titanium out to 1/2". Low speed, high feed. At 100 rpm, it was able to shear the bolt in the tailstock (the one that keeps it from rotating), twice. You WILL NOT stop the chuck with your hands...

[Verell]

"Do not carry the tool by its power cord".

LOL!!!
That's in the Travers manual also. Meant to mention it as it struck my funnybone as well! Heck, half the 'owner's manuals' you get these days are nothing but similar safety precautions. j

[Verell]

Did my 1st threading with the C4. I only cut threads about once every 6 months, so have to refresh my admittedly ageing memory as to how to setup everything.

Was cutting the end of an M10x1.5 socket head cap screw down to M8x1.25 so I could mount an A2Z CNC QCTP using one of the C4's T-nut slots. (Yes, I know that's a grade 12.8 fastener, I've machined them before with indexable carbide tips.)

I got it done, but in the process reinforced my dislike of feeding towards the chuck or workpiece shoulder:

I was cutting at 100rpm, which is the slowest the spindle will go under power.

1) I managed to grab the wrong lead screw lever (ie: the low feed rate/cross feed one - DUH) thus running the cutting tool into the shoulder (lost tip #1 of 3 on the carbid bit).

I switched to using the stop button about 1.5 threads away from the shoulder. Could keep my finger on the button, so much harder to do something wrong. Chuck seemed to stop after about 1/2 to 2/3 of a turn. & then just turning the chuck by hand to cut the last . This worked OK, but slowed things down a bit due to the manual operation.

Didn't need a threading dial (& C4 doesn't have one!), could just tap the reverse button, then the start button & let the lead screw back the threading tip back to the beginning of the thread cut, then quickly advance the cross slide, tap forward & the lathe would quickly stop the chuck & change direction, coming up to speed almost immediately.

About 1/2 thru, discovered the hard way that my thread relief at the shoulder wasn't deep enough. A bur started building up at the very end of the cut in what should have been the relief groove. Couldn't cut the groove any deeper as I couldn't disengage the lead screw w/o loosing synch between the carriage & the head.

Wasn't a big deal until the burr got big enough to overlap onto the adjoining previously cut thread. When that happened, next time I used reverse to back the threading point out, the burr came up under the point & broke it off(Tip 2 of 3 gone - ). I was really surprised when that happened, the burr was pretty small, but it sure took that tip off!

I indexed the 3rd tip into place managed to get thru the rest of the threading w/o breaking it(whew). The threads came out looking quite good, nice & triangular.

When I had the threads to the point that a M8x1.25 nut could be threaded onto the workpiece with a moderate amount of resistance, I got out a M8x1.25 threading die & made a pass over the threads. 1st try the die really didn't want to go without a lot of force, so I advanced the threading point another .002" & made another pass. This time I could get the die to go on, altho still took a wrench. The die really took all the roughness off & left the threads almost looking polished.

I need to make an 8mm T-nut, but meanwhile I got the A2Z mounted with a regular nut.

2 things really impressed me about the C4:
1. This thing is rigid!! To cut good threads on my 7x12 mini-lathe I had to really tighten the cross-slide & carriage screw nuts, and tweak the cross-slide, carriage, & saddle gibs up till they created noticable drag.

Didn't have to do any adjusting on the C4, just used it. Not the slightest sign of tool tip vibration! The cross-slide & carriage knobs turn so easy they feel like they're free-wheeling!

2. The C4's motor is POWERFUL!

Last time I used my 7x12 to thread a cap screw, the motor kept wanting to stall & i'd give the chuck a bit of hand assistance to keep things moving forward. IIRC,I was only making about 0.25 mm/0.0010" cuts!

Not the C4's motor. It never gave a sign that there was a load on it while the bit was cutting. I soon got the feeling that the C4 motor was going to turn no matter how deep a cut I was making. My suspicion is that if I tried to cut too deep, the load would break the carbide point long before the motor started to slow down!!!

[LouisP]

Hi C4-brothers,

I'm a newbie and it seems like you guys know what you're doing so here goes...

I just got my C4 and I'm having some trouble with the transverse (cross) feed. The longitudinal feed works great. I'm able to easily position the Cross/Longitudinal selection lever into the longitudinal position but not the Cross position. I think what may have happened, is that when I first powered it up, the C/L handle was in the cross position and when I engaged the Auto-Feed lever it drove it all the way in the -X direction and started making a "clicking" sound like the gears were not meshing correctly. I turned it off almost immediately after it occurred but now it doesn't engage any more.

I'm thinking that I may have destroyed one of the gears but I have a hard time believing that there isn't some mechanical safety mechanism that prevents such a stupid mistake. However, it is a Chinese lathe and I'm not so confident that such a mechanism made it into the product, so I'm guessing that I may have stripped a gear.

Any insight from you guys would be greatly appreciated!!!

Thanks in advance,


Lou

[JHanko]

I'm able to easily position the Cross/Longitudinal selection lever into the longitudinal position but not the Cross position.

To engage the carriage feed, you simply push the handle down. To engage the crossfeed, there is a mechanical interlock that prevents you from lifting the handle up. You have to move the handle to the left before you can lift the handle up. Hope this helps...

Jeff

[LouisP]

Hi Jeff,

Thanks for the reply. Yes, I know there's an interlock. But even if I move the carriage feed lever all the way counter-clockwise I cannot get the Cross/Longitudinal lever into position. Sometimes I can actually if I play with the manual cross-slide so the gears mesh into position but even then the cross-slide makes a weird clicking sound. The lead screw will turn a little, then click and thats it. I'm really starting to think I screwed something up and when I look at the mechanical drawings I cringe at the thought of having to open up the carriage mechanism!!

Thanks again Lou

[Verell]

Sounds like you're doing the correct things:
1)The carriage feed lever (I think of it as the 'fast carriage feed' lever, is this what you're calling the 'Auto feed' lever?) must be CCW ie: disengaged before you take the Cross/fine carriage feed lever out of neutral.
2)To engage cross feeding the cross/fine feed lever must be held to towards the headstock while pulling upwards.

Since you're doing the above, I'm afraid you do indeed have a problem require disassembling the carriage enough to figure out what's wrong.

Hmm, maybe you could just lay the lathe on it's side, remove the gearbox bottom plate & see enough to tell what's wrong.

If not, my experience with the SIEG products is that their mechanisms are usually pretty easy to understand, assemble, & disassemble.

Suggest you take pictures as you disassemble it, that way you will have them to reference when you reassemble it.

A quick look at the parts drawing it looks like the entire carriage feed gearbox will come off pretty easily:

0. Put the carriage feed lever CCW, & cross/fine feed lever in neutral.

1. Remove the lead screw.

2. Remove the 4 large hex cap screws holding the carriage feed gearbox to the saddle.

3. The carriage feed gearbox should then drop down & come off the lead screw's end.

4. Remove the gearbox bottom plate.

You should be able to see what the problem is w/o disassembling the gearbox.

[LouisP]

Thanks Verell for the suggestions. I'll do as you suggest and turn the late on it side so I can just remove the gearbox bottom plate. Hopefully I'll be able to see what's malfunctioning.

So, it seems that there isn't a mechanical safety mechanism that prevents you from driving the carriage (cross or longitudinal) hard to an extreme!! I would have expected that the "fast carriage feed lever" would disengage from the leadscrew if the system encountered too much torque! I guess not!

Anyway, I'll take a look tonight and take some pictures as you suggest. Particularly if I have to start disassembling it to figure out what's going on.

Thanks again... Lou

[JHanko]

I'm really starting to think I screwed something up and when I look at the mechanical drawings I cringe at the thought of having to open up the carriage mechanism!

Sorry about the confusion. I thought you couldn't get the handle to engage. It certainly sound like you sheared something. Probably a roll pin or an aluminum key retaining a gear on a shaft. It sure looks like your going to need to open it up. Good luck and let us know what you find...

Jeff

[Verell]

Louis, most machine tools don't have the kind of 'automatic' protection you're describing. For example, they'll happily let you run the cross slide into the chuck.

However, machine tools usually have a 'weak link' that's designed to break before major damage is done. Often the weak link is a soft metal or plastic piece such as an aluminum shear pin, aluminum or plastic gear, brass keyway, etc. Hopefully something like that gave way & prevented serious damage.

I suspect that if you were to run the leadscrew all the way to the end of it's travel using 'fast feed', that the very high torque might cause the motor to shut down.

I have some reason to believe this: Today, I was facing off a piece of Al at 600 rpm. When it reached a shoulder I yanked the cross-feed lever & managed to take it all the way down into fine feed(DUH). Yup, the tool quickly dug into the workpiece & the motor's overload protection shut it down. Put an impressive gouge into the workpiece, but nothing was damaged.

I'm less sure that the motor's overload protection would protect running into something under fine feed tho. This is because the fine feed drive is geared way down. Due to the large amount of reduction gearing, the motor only sees a very small fraction of the torque being exerted by the fine feed mechanism.

Hmm, upon further reflection , there's enough reduction gearing between the motor & lead screw so that even fast feed probably wouldn't trip the motor's protection before something gave way.

[bearbears]

Dear all C4 users, I'm looking to buy a C4 lathe and would like to use it for making some spinde for my router and I planned to CNC it as well but I have several questions want to ask before I go ahead.

How much spindle runout measured?
Does the finish of the ways good, parallel and flat out of the box?
Any lapping need to perform?
Do you think that the accuracy is good enough for that purpose?

Thanks!

John

[Verell]

The C4 quality out of the box is a enormously better than the 7x12 mini-lathes.

Have you seen Frank Hoose's review of a C4:
http://www.mini-lathe.com/m4/C4/c4.htm
He reported a spindle runout of 0.00002"/0.000508mm that's over an order of magnitude less than the mini-lathes!!!!

I haven't done any measurements yet. However, from the quality of the parts I'm making, the spindle runout & way flatness are very significantly better than the 7x12 lathes.

The carriage, saddle & cross slide all move extremely smoothly out of the box with nothing that would indicate any adjustment, mush less honing might be needed. I haven't even adjusted the gibs. The only adjustment I've made is to tighten adjust the split nuts for the cross-slide & saddle as there was almost 0.008" of backlash. Now I can't detect the cross-slide's backlash & the knob still turns without noticable drag!

I just looked at a parts drawing & was surprised to see that the C4 used the a flat gib system to hold the carriage down to the ways that looks fairly similar to the mini-lathe's system. I'd expect to eventually develop some of the problems that the mini-lathe's carriage gibs have. However, the C4's greater mfg. precision may mitigate that a lot.

One thing that's not mentioned in the manuals is that the C4 has a CARRIAGE LOCK!!! It's just a hex cap screw that pulls up on a flat plate under the ways, but it's very effective!

The bottom of the tailstock fits the ways perfectly. When I took a look at the bottom, it had the fine tooling marks characteristic of 'scraped' ways!

The surface finish on any metal I've machined is exceptionally smooth when using the fine carriage feed. This is machining with a fine point indexable carbide bit.

I'm making parts with it out of the box with as more precise dimensional control than I can get out of my mini-lathe after honing, tuning, etc it for a couple of years.The parts have been so good that I just haven't bothered trying to measure the lathe.

If the precision is anywhere near what Frank Hoose measured, I don't have the tools to measure it. Also, I'm not a good enough machinist to know how to go about making something that's that good even better. I suspect I just don't have the kind of tools it would take to improve it further.

I don't quite understand what your application's requrements are, but I can say that unquestionably the C4 will come closer to meeting it than a mini-lathe will.

The down side is the C4 is just plain overpriced, at least here in the US, & also the UK prices I've seen. It should be priced about the same as an X3 mill, & certainly not more than the Super X3 mill.

If you're CNCing the C4, you should be able to control spindle speed the way people are controlling the Super X3 mill's spindle speed. As far as I can tell, it's the same type of motor, possibly even the same motor.

If you don't need adjustable spindle speed or power cross feed, then the C6 is a larger & much more affordable lathe.

What I don't know is how the C4 would compare to the C6 for precision.

[squale]

how hard and expensive is it to cnc the c4 lathe?

what price do you think would be a fair price on the c4 lathe new? I know you said you think they are way overpriced here in the usa.

also, is this a good lathe to learn to machine on? I want to eventually get a cnc lathe but I think it might be better to start with a manual lathe.

[Verell]

IMHO,
If you're buying a new machine to learn on, get the Micro-Mark 7x14 mini-lathe. It seems to be being built to higher standards than the other mini-lathes, & isn't too pricey. If a 7x14 is too pricey, get a 7x12, it's still big enough to do a lot of useful work. You can get a Homier 7x12 for around $300.

DON'T GET A 7x10:
The 7x10 is miss-specifiied, it's really a 7x8 if you measure it the way the other 7x12 & 7x14 are measured. 7x8 is just plain too small unless you're always going to be making something really miniature stuff like N gauge train parts, & you can make them on the other 7x lathes as well.

I learned to use a lathe mini-lathe served me well for almost 4 years, it was a great learning machine. Not the least was knowing that if I really messed up, most likely all I'd do is break a cutting tool or a plastic gear. I broke a lot of cutting tools, but never a gear! Also, mini-lathe parts are readily available from LittleMachineShop.com.

Unless you're making seriously precision & fairly large parts, a mini-lathe is likely to be the most you'll need. I'm making production runs of fairly precision parts for my car parts business & molds for my injection molding business which is why I needed something larger.

IMHO, the C4 should be selling for around $1200, since the C6 is selling for about $900. By comparisoin, a mini-lathe sells for $300 for a Homier 7x12 (which is what I have) to about $450 for a 7x14.

[squale]

how does the Micro-Mark 7x14 compare to the C4?

[squale]

also what power do you need for the C4 lathe.. 110v single phase? or do you NEED to run a 220v line to the c4?