Here is a list of all the postings Pete Rimmer has made in our forums. Click on a thread name to jump to the thread.
|Thread: Myford ID grinder arbors|
Thanks Andrew. Your dims work out 3.486" / foot of taper my guess is that it's 3.5" / foot given the difficulty in measuring such things precisely.
I think that our ID grinding heads are very similar if not identical. The covers are obviously different because the MG9 motor is in the cabinet.
Mine is the same design Andrew. You remove a cast iron name plate then bolt the internal head in it's place. Remove the belt cover and bolt a large cast ally pully to drive the head with a flat belt and fit a cast ally belt guard.
My arbor nut has a 5/8"-20tpi RH thread and passes through 0.442". Does that sound similar to yours? If so I'd love to get some pics/dims of whatever factory arbors you have.
Also, how are your wheels retained? LH screws?
I knocked up a quick and dirty arbor to get me through the job at hand. It worked appreciably well but since I didn't have a LH retainer I had to watch for the retaining screw coming loose.
Incidentally, I found an arbor in the box of bits that doesn't belong to my grinder, it's much too large. I have no idea what it fits but the taper is a very close fit so I'm guessing it might be for a MG12 or some other ID grinding head. If anyone can identify it let me know please. I've put the basic dims below.
I have a MG9 grinder which came with the internal grinding attachment. It has one single arbor for holding ID grinding wheels which is obviously home made. I want to make a selection of arbors for the vaious grinding wheels that I have, it would help me a lot if I could get some pics and/or dimensions from anyone who has them.
The arbors have a steep cone that locates in the spindle and is held in with a collet nut.
Can anyone help me with this?
|Thread: making a Square|
You can buy them. Here's mine.
|Thread: Milling Table Flatness - What is acceptable|
If the error is in the top-to-way thickness there's nothing you can do to adjust it out. It's a very simple check you could even use a digital caliper if there's no micrometer handy. Checkig anything else before this basic check is quite pointless.
Measure from the flat way, the part that is actually in contact.
First thing to do is measure the thickness of the table from the top surface to the bottom flat way at the four corners with a micrometer. If they are not all the same you're not going to adjust it out.
|Thread: Boxford AUD/BUD single phase conversion|
Something like this would run it. Big name reliable brand, easy to install and set up. You can even download their free software and knock up a cheap patch lead to configure it from your laptop.
What size motor isit on your machine?
The white box is a NVR starter you won't be able to use that but you most probably would be able to use the original drum switch to the left of it.
EDIT you could use the NVR as a power switch to supply the VFD but you wouldn't be able to use it as a start/stop and depending on what model VFD you get using the E-stop on the NVR might invoke motor braking or it might allow it to run down normally. Killing the power to a running VFD is not recommended.
Edited By Pete Rimmer on 09/05/2022 21:58:26
Don't worry about going back to 3 phase after using a VFD you'll never want to.
I'm not familiar with the boxford switches but if they are momentary you'll be able to use them with a 3-wire control setup, if they act directly on the contactors it's a lot less straightforward;. TBH you might be better off knocking up a simple pendant control. Few, rev and speed can be done with a 3-way switch and a potentiometer is no time at all.
|Thread: Colchester Triumph 2000 - Topslide Leadscrew Threadform|
No it was just a nasty habit by Boxford/Denford. Most manufacturers use conforming threadforms.
I like the 29.5 degree option, You'll be hard-pressed to hand grind a tool to half a degree anyway without using a jig or rest.
|Thread: Question Re Camlock Chuck Fixings|
L0 chucks sell quite readily. I don't think you'll struggle with that.
|Thread: Toolco - Selling up|
I hadn't seen the previous link so I thank you for putting this one up. I needed a clamping kit for my new milling machine for when it's rebuilt and they had a couple of the correct size in stock.
|Thread: Tools needed to build a 3 1/2in gauge Tich|
Hi Steven and welcome. It's a shame you didn't come along 12 years ago when I was looking for a suitable recipient for my dad's part-built Jinty when he passed away, I would have gladly donated the lot . In the end I gave it to the local model engineering society for them to decide.
Just for interest - where are you located?
|Thread: help wiring a 3 ph coolant motor|
Steve I think it's unlikely that you would have a problem with a reversed field it would require the wires removed from the star point and swapped around with a wire from a terminal and I'm not even sure that even that would cause a problem on this particular motor. I f you have rough running issues then it's more likely to be mechanical, maybe debris in the impeller or even corrosion. I had a pump where the impeller was completely eroded away and full of white powder.
Swapping any two power leads is much easier and less likely to go wrong, for reversing a 3 phase motor.
What size motor is it Steve? I am looking for a small motor and VFD set for a small bench lathe I have. I also have a couple of very small VFD's suitable for a coolant pump going spare although I still say you should try the capacitor first it's a lot simpler and it's very cheap.
I believe that John Stevenson ran a coolant pump for years using nothing more than the capacitor out of a tube light.
Most small 3 phase coolant pumps will work just fine from 240 single phase with just a capacitor (steinmetz connection).
It's a bit of a jumble in there but it looks like you have red white and blue incomng power each on one post with one motor lead connected on each. The bottom post has three wires connected to it, that makes it the star point so your pump is configured for 415v.
Now, being just a coolant pump there is every chance that wiring your VFD to 2,3,4 just how it is will work just fine. Motor power will bevastly reduced but if it pumps enough coolant that's all you need. To configure the motor for 240v 3 phase (for your VFD) you would release the three wires on the No1 post and bring them each to 2,3,4 to form a delta. You can do this easily using a multimeter just split them all off and figure which is the other end of the coil on 2, connect it to 3. The other end of 3, connect it to 4, the other endof 4, connect it to 2.
If you haven't already bought a dedicated VFD for it though save your money and try it with a capacitor, they usually work no trouble at all.
Want the latest issue of Model Engineer or Model Engineers' Workshop? Use our magazine locator links to find your nearest stockist!
You can contact us by phone, mail or email about the magazines including becoming a contributor, submitting reader's letters or making queries about articles. You can also get in touch about this website, advertising or other general issues.
Click THIS LINK for full contact details.
For subscription issues please see THIS LINK.