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Member postings for Michael Horner

Here is a list of all the postings Michael Horner has made in our forums. Click on a thread name to jump to the thread.

Thread: What Did You Do Today 2019
10/09/2019 23:30:10

spindle2.jpgFinally got my calculated 18000 RPM spindle done. Motor and spindle get very hot so will keep me warm this winter. Hopefully will bring the machining times down, 10 hours was getting a bit long!

Cheers Michael.

Thread: strange power socket
15/08/2019 06:40:52

Hi Anthony

Wish I still had the fork with the bent prong! My mother kept it as a reminder.

I think that is why they eventually went to the shutter type of domestic socket.

On here they call it Darwinism! smiley

Cheers Michael.

Thread: Dam Solution?
07/08/2019 06:05:22
Posted by John Olsen on 07/08/2019 05:32:37:

. So since you are going to need a pump anyway, why bother trying to set up a siphon?

John

Using a siphon would only require energy to prime it then it would run for free.

Cheers Michael

Thread: Electric Cars
14/07/2019 07:12:10
Posted by Michael Gilligan on 13/07/2019 23:30:27:

The exit lanes merge into one after a reasonably short distance [the implied rule being that the two lines of vehicles will take their places alternately].

MichaelG.

Hi Michael

You answered your own question.

This would be my take on it, unless they are going to program in male aggression and selfishness.

The cars would agree amongst themselves who would be first away from the lights.

Cheers Michael

Thread: spindle bearings
19/06/2019 18:56:16

kx3 spindle.jpg

I got chance to fit the bearings today. It's not good.

Spun up the spindle in the lathe so only the ACB's were spinning, you can hear a noise and feel a vibration.

If you let go of the hub the noise and vibration disappear.

So it looks like I will have to dig deep and buy a pair of matched bearings.

Cheers Michael.

17/06/2019 18:25:02

20190617_172453.jpg

The cheapy bearings arrived today. I spoke to Ketan and he gave me some advice on fitting the bearings so will see how it goes. Probably fit them at the weekend.

Cheers Michael.

17/06/2019 18:13:03
Posted by RMA on 17/06/2019 17:34:24:
Posted by Ketan Swali on 17/06/2019 12:31:54:
Posted by RMA on 17/06/2019 08:36:45:

Yes I would generally agree with that, but the OP suggested two options including changing to tapers. Personally, if I was going to use the machine a lot and hard, I would change to tapers if the castings allowed for the mod.

Cost is another concern the OP has, but again it depends what the machine will be used for.

I understand, and after re-reading the OP, I also get where you are coming from. In that respect, you are right.

So, I need to clarify my earlier position. This is my opinion... Most machine designers have taken various factors into consideration, and reached a balance/compromise for the type of bearings they have used in the spindle of their machine. For this reason, I have gone along the line of changing like for like... where possible.

So, if one still wants to change the type of bearings which are in their spindle assembly, here are some of the points to consider...

For example, changing from general 'ball raced bearings' to 'angular contact (ball raced) bearings, will allow for a good improvement in accuracy. Similarly, going from angular contact bearings to Taper roller bearings will give a further improvement in accuracy.

The pre-load on bearings is one of the factors. All other things being equal, if you change from ball raced bearings to angular contact bearings, the max speed will reduce based on contact angle and pre-load, and the max speed will further reduce if you change to taper roller bearings, mainly due to the surface area of the rollers in contact with the inner ring, and how much pre-load is applied.

Another factor is the electronics. If changing from one type of bearing to another, one needs to consider the following: With more pre-load facility available for Angular contact bearings, the motor 'may' have to work harder to turn the spindle, and it may have to work even harder for taper roller bearings. The question then arises, is the motor up to it?, is the belt drive or gear train up to it? So, one has to consider the balance of pre-load to motor load to forces on the gear train/belt drive, to get the accuracy required. Are the electronics up to it?

Another factor is heat generation.. are the new bearings lubricated correctly with the right type of grease?, and is the quantity of grease put inside the bearings correct (usually roughly less than 20% of internal volume of the bearing). If this is correct, how will the pre-load on such assembly behave in terms of heat generation, if you change from Angular Contact bearings to taper roller bearings (TRB), when running the spindle at 6000 rpm?, combined with the load on the motor... correct running in procedure - short term high heat generation before settlement, etc...

In our experience, going from ball raced bearings to angular contact bearings is a reasonable change one may wish to consider. However, going from ball raced bearings, or angular contact ball raced bearings to TRB, especially where higher speeds are involved, is something one should be more careful about, keeping in mind the points raised above. For manual hobby machines upto 3000 rpm, this may be a small issue.... subject to control board overload protection/or not.

There are various other points, relating to the cutting tools used before and after such changes, and their effects on the tool - HSS or Carbide (which need higher speeds). As carbide seems to be a new fashion thing, reduction in speed could have deferent effects on the cutter, as well as the results.

So, really up to the person making the change to consider many factors before making a change.

You also made a good point with reference to TRB: 'if the castings allowed for the mod' and/or the inner spindle assembly allowed for it.

These are just observations ( I am not trying to create an argument). teeth 2

Ketan at ARC.

Yep, agree, especially about the regard to lubrication. I'm going back many year's now, but I had to investigate several bearing failures and most were due to incorrect lubrication. A lot of technicians/mechanics thought that if the bearing and cavity wasn't full of grease, it wasn't lubricated properly. Fact was the bearings churn the grease and increase the temperature so much that failure is inevitable.

Have to agree with the bit in bold. Whilst playing I filled up the knackard bearings with grease and couldn't believe the increase in temperature at 3000 RPM, burning hand temp . As expected the bearings were growling. I stripped it back down and washed out the grease and just used a sticky oil and it then ran barely warm.

Cheers Michael

16/06/2019 15:22:32

Hi old mart

Thanks for that.

Cheers Michael.

16/06/2019 08:26:43

The bearings in my KX3 are I believe are a cartridge type. The markings on the bearings indicate they are a matched pair (7007C). In the first instant I am going to fit a cheap pair of angular contact bearings and try and find a way to apply a preload. They are back to back bearings so preload is not guaranteed. Thinking of dropping a shim in between the bearings, press it all back together again then do a spin test, tweek the adjuster nut until there is slight drag then lock up the nuts and test. Otherwise its £170+ for a matched precision pair!

Cheers Michael.

15/06/2019 08:51:58

Hi Kevin

How did you get on with your bearing replacement?

I am in a similar position with my KX3, it took a hard dive into the job and took out the bearings.

Cheers Michael

Thread: Honing motor cycle small ends
12/05/2019 08:24:14

"I used to fit and ream the pin bushes on victa engines and used an old piston as a guide for the reamer to help keep it square , i used to have a piece of plate that fitted over the cylinder mounting studs and it had a slot cut for the conrod so i could sit the piston skirt on it and line the whole lot up and slide the expanding reamer in".

XD 351

You should win the John Stevenson Bodger award with that one.

Impressed!

Cheers Michael.

Thread: The Chocolate Fireguard as designed by Mercedes Benz
27/04/2019 23:31:34
Posted by Mike Poole on 27/04/2019 20:48:28:

Some people sit at a standstill with their foot on the clutch, I do use the neutral selection on lights I know have a long sequence, I often turn off the irritating auto stop. The car wash is a bit of a problem with the low profile tyres as the guides can touch the rim of the alloys, the lads at the hand wash do a great job but the pressure washers are pretty fierce.

Mike

I believe I.A.M's recommend being in gear at the traffic lights so if things go pear shaped there will be some measure of control, I did query that this meant the engine wouldn't switch off and the reply was safety takes precedent over emissions.

Cheers Michael

Thread: Mini lathe
19/01/2019 21:27:45

Hi Jeff

The disc with the numbers, the splined shaft fits underneath and meshes with the lead screw.

Cheers Michael.

Thread Dial.jpg

19/01/2019 20:43:12

Hi Jeff

I suspect they are for the threading dial, you should have three, one may be already fitted under the dial marked 1 to 12. They have different number of splines depending what pitch thread you are cutting.

Cheers Michael.

Thread: Mini lathe speed and tailstock question
14/10/2018 19:31:05

Hi Jack

The white dot looks off white and the sensor bracket doesn't look like it is at 90 degrees to the dot. My RPM display is an extra and uses a reflective opto and if things aren't just right can give wacky readings.

Cheers Michael

Thread: Bench grinder improvement mod.
08/10/2018 07:36:51

For this, I added larger flanges, using adhesive, to the grinders spindles and turned these true with the grinder running whilst fixed to the lathes bed. The advantage of this, together with the accurately made adaptors, is that the wheels can be interchanged and only need truing up the first time they are run.

**LINK**

The above is from Harold Halls website of how he dealt with the issue.

Cheers

Michael

Thread: Automatic Centre Punches
23/09/2018 08:01:13

Hi Terry

I have. Wish I had seen Michael G's info. Went all round the houses trying to get it to work.

To me shaft 17 canted over is the key. I put a ball bearing on the left hand side, the right hand side wants to be flat and so does 23.

As the spring is compressed the 2 cones come together and make shaft 17 drop down the hole, this is the hammer action.

On my punches the wear made it drop down the hole to soon.

HTH

Cheers Michael.

Thread: Yet another parting tool question...
27/08/2018 12:08:11
Posted by JasonB on 27/08/2018 10:13:31:

I don't understand why the first type is advertised as a parting tool only, but the second as a parting and grooving tool. Can anyone enlighten me about the functional differences of these two designs of bit holder?

Robin

Michael, Neil and Andrew,that holder that Michael shows is not what the OP shows. The tip are different and have better side cutting geometry and can therefor cut sideways which is why the MGEH is also described as suitable for profiling, even more so with the round nose inserts.

The QA-GTN that the OP posted just uses a standard GTN parting insert but due to the holder being stiffer (sideways) will be better able to cut sideways but at the expense of not parting as deep as the blade type will allow.

Edited By JasonB on 27/08/2018 10:16:47

Hi Jason

Must have misread the post. Robin went on to mention the second type which I presumed was the profiling one.

Cheers Michael.

27/08/2018 08:51:56

ARC MGEH one piece clamp type Parting & Grooving Tool Holders

Suitable for external grooving, parting, turning, relieving, profiling.

Each tool holder includes:

  • MGMN200 TiN coated insert
  • Hex Key

ARC MGEH Parting and Grooving Tool Holders - DiagramsHi Robin

Can you see the left arrow above the grooving arrow?

This tool can take small cuts side to side.

Cheers Michael.

Thread: What did you do Today 2018
15/08/2018 23:30:09

Made a straight knurler along the lines of Vics' design. Slipped up with the lower pivot and have now corrected the oversight. Need to finish of the top. Maybe put a big knurled knob on it!

knurling tool.jpg

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