Chinese lathe upgrades.

[PaulsM]

For those suggesting brands / venders Paul is in Latvia so US suppliers are probably not much help.



The bearings you refer to are live centers, the solid type are dead centers.

The tool post is a quick change tool post, the one pictured is an Aloris type, which is the most common style. You will probably want an OXA size, but a lot of people with 9x20" lathes prefer the AXA size. The MX750 has an 8.7" swing which is nearly the same as the 9x20s 8.75" but can't say for sure that will work for the MX750, so OXA is probably the safer choice.

This type of tool post can be had as the wedge type or piston type, the wedge is preferred, but both work. The one in your photo is the wedge type, named for the moving wedge that locks the tool post. The piston type is simpler so sometimes cheaper and has a round piston that extends from the body to lock the tool holder.

I would look for a tool post made of steel, some are made from aluminum and not as solid, but again often cheaper.

You will probably want to get additional tool holders, most just come with a few holders to get you started.


If you are going to be working on pipes, you may want to get a bull nose center. These have a broader point to fit into the end of a pipe or tube. They come in different sizes to fit different size tubing. The point on a standard center will not hold a very large piece of pipe or tubing because they are usually only 1/2"-1" / 12-25mm in diameter. Bull nose centers come in much larger sizes 2" / 50mm, and 4" 100mm being common.

First of all, thanks everyone for an input
This is bull nose? If pipes I have are electrowelded with a seam along them, I should turn inside before using this tailstock?

 

[savarin]

or use a small grinder like a die grinder

 

[Aaron_W]

First of all, thanks everyone for an input
This is bull nose? If pipes I have are electrowelded with a seam along them, I should turn inside before using this tailstock?

View attachment 433868

Yes, exactly. You just need one that is larger in size than the pipe diameter.

I've not actually turned any pipes or tubing requiring a center, but yes you will want a nice straight and clean end in contact with the center.

 

[Chip Hacket]

If you can get a grinder and some high speed steel like savarin suggested, you could grind yourself a boring bar to clean up the inside of the pipe. If available to you the inexpensive carbide tipped boring bar sets may be useful as well and you won't need to grind them. Good luck!

 

[savarin]

To bore out the inside of your pipe you really need a 4 jaw chuck, a fixed steady and a magnetic indicator

Indicator Magnetic Base Metal Test Holder Digital Level Tool | eBay

It can used for dial indicator and lever dial indicator,etc. NOTE : This item must be put in the magnetic plane. One magnetic base. 1 x Magnetic Base. There is On/Off switch on the base. Base Size(L x W x H): Approx.

www.ebay.com.au

to get the pipe centered as best as possible along its total length. If you only have the three jaw then try to keep it in the chuck without removing it untill both inside and outside operations have been performed.

You may have to turn a small section of the outside of the pipe where the fingers of the steady will touch as I doubt the pipe will be perfectly round. If your using water pipe I expect the outside will be galvanized, as you turn this layer off you will notice how out of round the pipe is.
By grinding you own HSS tool bits you can make your own boring bars, heres three of my simple ones.

Notice that the left hand one has a flat ground/filed on opposite sides, this was so it would fit into the 4 way original tool post.
The right hand one is using a broken tap ground to shape as the tool bit. (never throw broken taps away as they can be used as tool bits)
The shafts are nothing special just steel I had laying around.
Another tip, I visit local machine shops to ask if they have any drops, explaining that I'm trying to teach myself how to use a lathe for my hobby (telescope making) 99% of the time they are very helpfull.

 

[savarin]

Heres a bit of water pipe I took a skim cut to remove the zinc that shows the welded seam and the wide sunken patch that ran the full length of the pipe. Its interesting that the welded seam is a different colour to the parent metal. I am assuming its either the heat affected zone or filler metal.

 

[tghsmith]

unless you deailing with short sections of pipe a steady rest might be a good to have..

 

[PaulsM]

Any suggestions what is a good "brand" on aliexpress for cutting bits?
Also, could someone explain MTA and MTB?

 

[PaulsM]

Also, I have a wobble in this part, I see it can be tightened, but how much is enough?

 

[matthewsx]

Not sure which brands on AliExpress are good but I've used the cheap ones and they will chip if not treated carefully.

MT2 and MT3 are two different sizes, here's a reference doc. https://solutions.travers.com/metalworking-machining/how-to-determine-your-machines-taper-size Edit: Sorry, the difference between A and B in the picture you posted is the tang on the back which is used for driving the taper out of (usually) a spindle. It may not be needed for a tailstock which has a screw which should eject the taper when you retract the ram all the way back into the tailstock. You can always cut off the tang if not needed should you purchase type A.

Yes, tighten up that piece on the back of the carriage as tight as it'll go and still let it move freely, make sure you have plenty of way oil in there too.

John