Member postings for Huub

Hello Richard ,

Learning milling, requires some time. Even a top quality milling cutter can be blunted in seconds. I would start by buying a few very cheap HSS milling cutters and drills.
Once these are worn down, you could buy a more decent one.
Once you get a decent life time out of your HSS end mills/drills, you could move to the HSS Co5 end mills/drills. These are a bit more expensive but they last a few times longer than plain HSS end mills.

You find a lot of settings for milling and drilling. Most of the time, these settings are for rigid machines and won't work on your milling machine. You have to find settings that work for your setup. Basically I reduce the advised feed/revolution and cutting depth until I get decent results.

I grind my own milling cutters/drills and don't want cobalt dust in my shop. So I buy the hardest HSS grade without Cobalt (HSS M2).
I also use round lathe inner turning bars with inserts (DCMT070204) for hard to mill steel and to remove the first layer of hot rolled steel.

I have 2 Chinese vices (80 mm for 70€ / 100 mm for 120€  that are of poor quality. I used the mill to make the first one more decent. The second vice will be improved when I have a new milling machine. I can still make steel parts within 0.02 mm.

Success with your new machine,

Huub

Edited By Huub on 10/06/2023 23:12:23

Edited By Huub on 10/06/2023 23:12:59

I would do this on a lathe and start by the making the inner hole using drilling and turning.

If the thickness of the washer has tight tolerances, now would be the time to face one side of the washer.

For the outer diameter I would clamp the inner hole on the 80 mm 3 jaw chuck from my mini lathe (the faced side towards the chuck).

Face the other side of the washer.

Turn the outer diameter + 0.5 mm) using the trepan method or turn the outer diameter using modest depth of cut.
Turn the outer diameter to the final dimensions.

The gibs need to keep the play at a minimum. If there is on even wear along the bed, these elastic gibs will partially compensate for that. When using brass or aluminum gibs, the carriage will get stuck.

I would first try to set the play at a minium and check the result.

I have made brass gibs for my mini lathe. Any type brass will do.
If I have to do it again, I will try POM gibs because they don't wear down the bed. This allows me to set the play to zero and probably the carriage will be hard to move at some points. But that is only for a short time until the POM gibs are wear down a bit.

I hope, I understand your problems:

You are showing a thrust bearing. This bearing has to different bearing races.
One bearing race has a very very lose fit for the shaft. the shaft should not touch this bearing race when turning the shaft but the bearing race should fit tightly in the bearing housing.
The other bearing race has an almost press fit for the shaft. It should turn together with the shaft but be clear of the bearing housing.

For testing the sliding surfaces, you should place the 2 milled/ground/scraped surfaces together. So that the 2 sliding surfaces touches each other. Then check the rocking of the table.

You can run any tool at any speed. However, if you run to fast, the tool gets to hot, loses strength and gets blunt fast. If you run to slow, the chips will be cold and tough and the tool gets blunt.
At higher speeds, the chips get hotter and softer resulting in a better finish. The same when feeding faster or taking deeper cuts.
Also the chip breaker on the tip is designed for certain range of speed, feed and cutting depth combinations.
At some point, your lathe/mill will start flexing when the stock has impurities or is inconsistently and your finish will be lesser.

Larger inserts can take heavier cuts and are more likely designed for rigid machines. On my hobby machines, I use small insert like CCMT060204, DCMT070204 and TCMT110204.

I run HSS at 30 m/min on steel.
Most of my carbide inserts go from 90..300 m/min on steel and I try to run these at their max speed.
I run my brazed tools at the speed of HSS. Never tried to run faster and I don't use them often!
For finishing passes, I feed at 0.05 to 0.1 mm/rev and use a 0.2 to 0.3 mm depth of cut.

Edited By Huub on 16/05/2023 23:46:32

Edited By Huub on 16/05/2023 23:47:09

Edited By Huub on 16/05/2023 23:47:52

I have a Chinese mill and a Chinese vice. None of them is really accurate. So I made parallels on the mill from mild steel. Marked a corner so that I can place them the same way they are made.

Now I have a reasonably accurate result, most of the time within 0.02 mm. When I damage a parallel, I just mill the top flat again.
Noway I can achieve the same or better accuracy with accurately ground parallels.

In time, when I have a new milling machine, I (maybe) will adjust the vices using a pair of 123 block.

I have a 80 mm vice that is 65 mm high. I use it for most jobs. For large stock, I have a 100 mm vice that is 95 mm high. I can only use it with short mill and drills.
The rotary stand for both vices is only place when needed. It just takes up to much space and makes the vices less rigid.

My next mill must have a longer 500 mm (20" table (Y) and must be considerably taller.

If the spindle has 2 lock nuts or a slitted nut, than it is probably fitted with contact angle bearing that can be adjusted. Unlock the nuts and adjust the play by locking the nut (just use your fingers, no tools). This will apply some preload on the bearings and will reduce/eliminate play.

When you measure play, place the indicator on the top of the head stock, not the bed. You don't want to measure bending of the bed or play because the head stock is not tightened to the bed or the chuck is lose.

Put a bar in the spindle, lock the spindle and measure the play close at the spindle. Measure the horizontal and vertical play. To measure play, you don't need a lot of force. 2 kg/4 lbs is more than enough.

You can also check the documentation about the type of bearings used in this lathe.

A picture of a slitted nut, my favourite for locking/preloading contact angle bearing shaft.

Edited By Huub on 02/05/2023 23:18:22

My mini lathe has an indicator in mm. So to adjust the diameter, you have to divide the difference in measured and requested diameter in 2. Not a real problem but still a source for error.

My bigger lathe has a dial in Ø, that is easier to use and is my preferred dial. Luckily making a dial is not so complicated so a custom dial can be made.

I would mill the rectangle blind hole using an 8 mm end mil, cleanup the corners using a 6 mm end mill and finally broach the 4 corners using a ground HSS square tool bit.

Rotary broaching a rectangular blind hole is not a problem. You can't get to the bottom all the way. The long cutting edges generates high cutting forces. You could mill the hole and rotary broach the round corners square. I expect you get to 1 mm off the bottom.

You can do the same with a square broach if you do the corners one by one.

My largest M6 (M6x1) hand tap is 21 mm. The machine tap is 23 mm and the dril/tap bit is 19 mm. I would drill M6x1 5 mm for steel and 5.1 mm for stainless. Always use cutting oil.

The machine tap requires the lowest tapping force because is only has 3 starter threads.

When the tapping force increases, the tap will twist and that will increase the tapping force even more.

beltingonline.co.uk

I would give it a try. You can also use the clutch on the cordless drill for some form of protection. If the bolt on your lathe can be tightened to the max , you can replace the bolt by a hex bolt and use a piece of hex steel to drive the nut.

No you are not. Hand feeding can do the job also and if you are experienced and have good results why not.

Some times I also use a 1.2 mm HSS parting blade in normal position and manual feed. When I have time, I will make a tool holder for a 2 mm HSS Co8 blade that I want to try.

Power feed (CNC), upside down parting tool and lubrication is my way using a SP200 2 mm wide insert, 800 RPM (max to keep the lubrication on the part) and 0.02 mm/rev.

After parting off years at these conditions on both my lathes, I recently started parting off steel dry to allow higher RPM (higher speed). I am not sure if this is a better condition, will try it for several weeks.

My mini lathe also has 1 half nut and is constructed the same as your myford lathe. On my mini lathe, There isn't enough space for a second half nut and a lead screw protection. Nevertheless, even with one half half nut, it serves me well over 10 years now.

The B16 chuck has a thicker shaft and is more rigid.

The B16 chuck has a longer clamping length and is more suitable for clamping end mills that have a Weldon shaft (flat area on the shaft)

I bought last year the most expensive professional keyless chuck from Paulimot Germany because I didn;t want to wait long. I is the worst piece of shi..... I have in my shop. Has a +0.1 mm runout above 8 mm diameter, the holding force is terrible, the taper is terrible, and it can't be used for tapping because in reverse the tap get lose.

My best drill chuck is a 30+ years old abused chuck from Röhm. The 13 mm keyless Röhm metal drill chuck on a €55 Lidl cordless drill is better than most drill chucks I have.

What you should buy, depends on what you need. I bought a 16 mm MT3 drill chuck from Paulimot for €8,-- that was advertised as "runout out of tolerance" and I use it to hold my tapping holder, great buy.

Inserts and their application is a discipline of its own.

These round inserts have a enormous "nose radius". They will give a better finish than inserts that have a small nose radius like a CCGT060204. A large nose radius results in large cutting forces. So these round inserts are not used for rouging but for finishing jobs on a rigid lathe.

The different colours shows different coatings and each coating is optimised for a certain material type and turning conditions.

You can also see different chip breakers. Chip breakers are also optimised for material types and turning conditions.

The shiny ones (middle row), are probably polished inserts. These polished inserts have very sharp cutting edges and are commonly used for aluminium and plastics. On non rigid lathes, polished inserts that have a small nose radius like CCGT060202 and DCGT070202 give good results when cutting steel, stainless or titanium.