Thread: Home Made Lathe

Originally Posted by pipeclay

Might be time to invest in an other couple of tools,dial indicator and magnetic base and a couple of micrometers.

I think your right PC i most defiantly need the dial indicator but unsure about the magnetic base as my whole lathe is aluminium i could possibly bolt the base of the dial indicator arm to the back rest/post of the tail stock

this is my second set of vainer calipers the first one i ordered on ebay was absolutely terrible the reading jumped all over the place, the second one i thought i would spend a little more money on and a walk in the shop to buy i picked up this one from Super Cheap Auto it keeps turning on and off as it pleases so i think i need a set of the manual micrometers the C model ones but they'll have to wait a little bit

pictures still won't load to this site of the dial readings

Originally Posted by gazza2009au

It goes 0,0.2,0.4,0.6,0.8 back to 0, when i previously mentioned i was cutting 0.5 that was 5 lines or between the 0.4 and 0.6 markings

I'm still unsure if this lathe is metric or imperial, i tried machining down the 36mm stock i cannot remember what number i came to but it was a even number than i took off from memory 0.2 and it took a lot more off than 1/5th of a millimeter but again i cannot remember the exact sizes but i do remember thinking this may have been a imperial machine

unless where i am going wrong is the machine reads 0.2mm but really its machining 0.2mm off the radius so there for 0.4mm? i donno i can't work it out i have tried tho

With markings like that it's likely that it's metric. There are 2 schemes in use for the dials depending on the manufacturer, either the markings denote the depth of cut (so moving the dial from 0 to 0.2 results in a cut of 0.2mm resulting in a reduction on diameter of 0.4mm) or they denote the reduction in diameter (so moving the dial from 0 to 0.2 results in a cut of 0.1mm and a reduction in diameter of 0.2mm). It's likely to be the latter but the easy way to test is by making an initial cut with the dial set to 0, measuring the stock diameter then moving the dials to, say, 0.2 - taking another cut and re-measure the diameter and seeing whether it has been reduced by 0.2 or 0.4 mm.

Originally Posted by gazza2009au

with these little hobby/toy lathes i can bring them inside and place them on the kitchen table

It's only 560mm long and 25kg, it might still fit, if you have a sturdy kitchen table.

If you really have to stay in that size bracket, perhaps something along the lines of SIEG C0 Baby Lathe (Adjustable Tailstock) with Accessory Pak would be worth a look?
I have to imagine with an actual cast iron bed, it would be significantly more rigid than those aluminium extrusions.

i picked up this one from Super Cheap Auto it keeps turning on and off as it pleases

You can pay quite a bit of money for calipers from local stores and probably get the same junk that is available on EBay for a fraction of the cost. It is a bit of a lucky dip. I have a cheapie that will not hold zero very well.

Dean

Thanks thats how i thought it worked is there a possibilty of the manufact combining the two measurements on the one machine? I still havent worked out how to start off at zero settings as there are to many variables

Haha 25kg would make my table topple over could be disasterous lol i like the baby sieg i would need to save a couple pennies but its a model i will look into more

I'm 2 from 2 with digital calipers i think i really need the C shape mechanical caliper nothing can go wrong than i will slowly sift thru the bad gear and sort out the good tools

Sorry for the 3 post guys i'm on me mobile

Re zero'ing the dials
On the picture you posted it appears that the lines are on the dial itself, on bigger lathe's you will find that the numbers are on a collar that sits on the hand wheel, the collar is allowed to rotate with a little force. There are different ways to preload the collar so it doesn't free spin, be a wave washer or whatever other means. This means you would normally crank the tool it, normally touch it off on the material, then hold the hand wheel to stop it from rotating and spin the collar around to the zero mark, take a cut on the material. When you then measure the material you can work out how much you need to take off.
Your lathe not having a spinning collar is not the end of the world, my suggestion would be grab a white board marker, when you touch the tool off on the material draw a line with your white board marker. That mark is now your zero spot. When your finished just rub it off, only white board market after all.

As mentioned dials can be set to read either radius or diameter reduction. That little lathe, no idea which it will be. Setup some material, touch off the tool, mark your line, take a pass, crank it in a bit and take another pass. See what the change was and try work it out that way.
Alternately you could pull the screw out and measure the thread pitch and compare it to the dial. The hand wheel for the cross-slide will be direct acting so if you know the thread pitch and divisions on the dial you can work it out that way.
Hell you could even just mark where the cross slide is, crank it say 5 full turns, measure how far it moved and work it out that way.

Don't however rule out the possibility that the manufacturer just whacked together whatever parts they could get that where cheap / off the shelf. You will also find if you take a deep cut it will cut less then you fed in due to slop in the machine and if you follow it with a light cut it can overcut because it's picking up some of the undercut from the heavier cut. Eg feed in 1.0mm, cuts 0.9mm, then feed in 0.1mm and will cut 0.2mm.

Hope this helps

Thanks MS that was very helpful i thought there had to be a way of zeroing out the machine,

I now have the option of upgrading from the small 24watt to the 60watt model or i can buy accessories for my exsisting toy lathe

What would u guys chose? Budget is not much but i can upgrade to the more powerful toy lathe but my budget doesn't stretch enought for a H&F lathe

Skip the 60watt model, it's going to be less rigid then your current toy lathe, you can see that there is another extrusion under the headstock / tail stock to give the extra height.

if your keen to spend some money on the toy lathe have a look and see if you have space to put a insert tool holder in. I know some people will disagree and say to just sharpen the HSS but if you don't know what your doing and don't have someone that can help you it will end up with an incorrect tool and poor results. Each time you sharpen it you will need to shim and adjust it to get the tip of the tool on centre height. If you get an insert tool holder I'd put it where your T-nut clamp goes at the moment and make another clamp. Inserts will last a life time on that small one and if you just get something like this

SCLCR0808F06 8 x 80mm CNC Lathe External Thread Turning Tool Holder For CCMT0602
and a suitable aluminium insert
eg
https://www.aliexpress.com/store/pro...619460328.html
You should get better results, these inserts have the proper geometry and coating.
(if you go that route then you want to know the height from the cross slide T-slots to the centre height, you can get tools to suit 8mm, 10mm, 12mm ect. You may need to get one that is slightly too big and get someone to machine it down a bit if yours isn't exactly one of those sizes)

otherwise just buy generic tools, vernier calipers, DTI & mag bases, ect ect

I see a problem since this is a micro lathe if i use one of those tools it looks like it might take up a lot of the chucks max diameter so the pieces i machine will be limited to probably 27-30mm

my tool is 4mm i tried looking for those tools with replaceable cutters but there were none in this size i think that's why u mentioned to get one machined

Doesn't look like the handwheels are adjustable going on previous picture. Small matter, nothing wrong with memory or pencil and paper, I very rarely adjusted mine, only on threading really. By now you're probably thinking of all the things you can do with the lathe and wondering how on earth you ever got by without one.. I very rarely use mine now, but still I think the lathe will be the last machine I will sell off, just too handy. Incidentally, turning metal down is just one operation you can do on the lathe, only your imagination will limit you. All you need now is a bandsaw, welder, mill, pedestal drill, bar bender, rotary table, belt grinder, tig, mig, box brake, full suite of Milwaukees or Makitas, drill sharpener, tool and cutter grinder and probably a bigger shed!

Originally Posted by gazza2009au

i think i really need the C shape mechanical caliper nothing can go wrong

That would be a micrometer then! Not his one though as its only 0-25mm whereas if your stock was 40mm od , a 0-50mm.


mic.jpg

Originally Posted by gazza2009au

I see a problem since this is a micro lathe if i use one of those tools it looks like it might take up a lot of the chucks max diameter so the pieces i machine will be limited to probably 27-30mm

my tool is 4mm i tried looking for those tools with replaceable cutters but there were none in this size i think that's why u mentioned to get one machined

Why I asked about the about the HSS cutting tool dimension is that they are quite cheap on ebay and if you are only machining aluminium or plastics a Chinese made HSS may well do the job.

4MM X 4MM X 200MM LONG BLANK LATHE HSS SQUARE TOOL BIT | eBay

Note that it is US $ but I am sure something could be found on Ebay au

It could be cut to length with an angle grinder thin cutter blade. you may get 4 or 5 from a 200mmm length.

Grahame

Originally Posted by Grahame Collins

That would be a micrometer then! Not his one though as its only 0-25mm whereas if your stock was 40mm od , a 0-50mm.


mic.jpg

These can be bought in digital too. The calipers can also be bought in dial type and vernier type which are more reliable.

Dig Mic.jpg
Dial Cal.jpg
Ver Cal.jpg

A micrometer is essential for accurate readings, but a caliper is handy for quick readings while you are getting to near final size.

If you need to do any boring, insert type boring bars can be bought down to 6mm diam.

How have you set the centre height with the 4mm HSS? How do you check if the cutting edge is on centre?

Dean