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Member postings for Ronald Morrison

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

Thread: Calipers - Dial v digital
01/12/2020 10:37:18
Posted by thaiguzzi on 01/12/2020 04:54:25:
Posted by ChrisH on 28/10/2017 10:47:31:

Andrew - I like you method of working, very sound, but not all - perhaps very few, I don't know - of us have the grinding facilities to accurately grind hole plug gauges parallel and to size, we have to make do with the measuring tools we have, but as you say, you can't have too many micrometers, inside and out! I need a depth one now too.

thaiguzzi - quality verniers are very good but the problem using them you have identified, eyesight. That doesn't get any better as you get older and a lot of us here are not so young as we like to think! (Think mind making promises the body can't keep anymore. You think you are still 27 but the reality is more like 72!). That is why digital and to a slightly lesser extent dial calipers have their attraction, big figures easy to read.

Chris

Bump.

Well, 3 years later, just turned 60, and my Mit verniers are finally getting awkward to read on the imperial scale.

Being a Luddite, and refusing to have anything to do with digital, batteries or electronics, i am now looking at dial calipers.....metric and imperial....

It's time for you to join the 19th century and move to digital. The fact that your eyesight has changed enough to move you from a vernier tells me that in a few more you won't be able to read the dial caliper either. Voice of experience. Buy a cheap digital caliper and a pack of batteries as the the cheap calipers use batteries more frequently than the more expensive ones. Use that digital caliper for a month, using it's ability to switch between imperial and metric measurements and being able to reset zero to read incremental measurements instead of having to calculate how much stock is left to remove. Use it lots in that month. Then rethink whether you want a dial caliper or not.  By the way, you only need one spare battery, not an entire pack.  My most used digital needs the battery replace about once per year.

Edited By Ronald Morrison on 01/12/2020 10:38:32

Thread: Neil's thread re review of digital calipers
28/11/2020 12:10:27
Posted by jason udall on 27/11/2020 18:13:13:

Carbon fiber framed are available.. Around Fiver each.

Can't say I've experienced them but frames made of low thermal and drill able material has potential of adding simple direct measurement to various axis .

I have a cheap carbon fiber digital caliper. I use it all the time but I do note that the accuracy is only 2 digits imperial instead of the 3 digits of the stainless steel one. Quick measurement to get an idea of the size, the carbon fiber framed one works fine. If I need more precision the stainless steel one comes out.

Thread: EBAY
28/11/2020 12:02:57

Wild guess about why people want to call Ebay, Fleabay. Being cheap as some are wont to be, they found a "bargain" and without doing any research on the item or the seller, hastily made the purchase. When the item arrived they were upset because it wasn't the same quality as that item from a well known name would have been and thus called it fleabay as a slightly derogatory name.

Thread: Bearing identification
27/11/2020 11:08:49

if you spend enough time on bearing manufacturers websites trying to sort out the terminology the use so you can compare the various bearings between suppliers you will become more confused and frustrated. Unless the bearing is a very special application that requires high precision and high speed operation, just measure the ID, OD, and width and pick a bearing. If the lip seals won't keep the dust out, nothing will. Greasing the bearing won't be of much help as you can't push out all the dust that is in the bearing but simply dilute the grease/dust mix that is in there. Hopefully the location of the bearing will make for easy replacement. Buy 2 or more and store the spares where you can find them.

26/11/2020 09:53:39

Wild guess? Speed of operation. Most bearings in agricultural use are slow turning. Other bearings might need better quality as speed is much higher. Now you need to explain where the bearings are used. What kind of agricultural equipment and where on that equipment?

Thread: Left Hand Acme Threads
25/11/2020 11:21:13

Is there a reason you can't use a Delrin (acetal) nut? They would be much easier to machine that metal and can be melt formed to the acme screw you have for a nut with near zero backlash.

Delrin leadscrew nut

Thread: Insert for internal ACME thread?
20/11/2020 01:02:42

Do a quick search for the word "evanut". Near zero backlash.

Thread: unimat 3 problems with support twist
18/11/2020 01:50:25
Posted by Jouke van der Veen on 17/11/2020 21:14:46:

I just found on the Internet that the original Emco C5 CNC motors had a holding torque of 0.5Nm which would mean that a Nema17 could do the work. A difference, however, would be that the Emco motor operated a ball screw for moving the cross-slide. Moving and holding a, for instance, 6mm trapezoidal spindle by means of an injection molded nut might ask for a higher torque, isn’t?

NEMA17 is the frame size of the motor. They come in different lengths with differing torques. It does appear that they range from 0.23Nm to the 0.5Nm so they might not work for this application. The size is approximately 43mm square. A NEMA 23 has much higher holding torque and is only a bit bigger at 57mm square.

Thread: Draft Site change of status and program down load not working
17/11/2020 12:34:02

FreeCAD

Can you import your Draftsight files to FreeCAD? It's free and open source and allows both 2D and 3D modelling.

Thread: Parting off with a 5/6" toolpost
17/11/2020 12:21:12

You might have to do some talking with the seller and pay shipping since this offer is free shipping to the US only but this set of 5/16" tools might be what you have been looking for.

 

https://www.ebay.com/itm/8-Piece-TOOL-BIT-SET-HSS-5-16-SQUARE-BY-3-25-LONG/303667134334?hash=item46b3f8bf7e:g:b4IAAOSwQyBfCdF7

Edited By Ronald Morrison on 17/11/2020 12:21:57

Thread: unimat 3 problems with support twist
17/11/2020 11:45:15
Posted by Jouke van der Veen on 17/11/2020 11:06:49:

When you look for “Non-captive Stepper motor” on Internet then you will find them.

The spindle is sticking out of the motor on both sides and can move from one end to the other through the motor.

My question is: what mechanism moves the spindle and how is backlash minimized.

Perhaps I should open a new topic about it.

I don't really know as I have none to look at but from researching it appears that the non-captive stepper has an integral ball nut that is rotated to push or pull the screw. The screw does not rotate so it can be fastened solid to whatever you want to move and the very minimal backlash of the ball screw makes it accurate.

Thread: Solid Rubber Oil Seal
09/11/2020 15:07:09

Speaking with the seal suppliers without knowing the exact name of the seal can be frustrating. If you can take one of the old seals to a hydraulic specialty shop, just looking at it will likely to get the exact name and they may have them in stock.

Thread: Sieg C1 lathe autofeed and screw cutting
03/11/2020 11:00:21

The fact that the lathe motor can be run in reverse makes threading to a shoulder for imperial threads much easier. With the motor running in reverse use a boring bar with a thread cutting end on the backside of the stock , bring it to the shoulder, then engage the "half nut'. Now you cut threads away from the shoulder so you don't have to have lightning reflexes. Making a stop for the carriage lets you set the starting point so the tool never hits the shoulder.

Thread: Calliper - Dial reading
02/11/2020 21:44:56
Posted by Clive Foster on 02/11/2020 20:31:06:

Dial callipers don't have a battery to go flat on you when needed.

I'm prejudiced. With maybe 50 or so micrometers, verniers, callipers and similar about the place going electronic isn't going the happen!

One day I should do a proper census.

Clive

If your eyesight starts to go bad the fact that you have to replace a battery occasionally will not bother you so much as not being able to see the numbers on the dial nor the lines on the vernier. I have to replace the battery about once a year on each of my digital calipers. Since I know that, I keep a few spares on hand.

02/11/2020 20:04:48

Why not save yourself the agonizing over the metric dial caliper and just get a digital? The cost is not much different, the digital has numbers big enough to read and with a quick push of a button becomes an imperial caliper. Very easy to set a new zero as when you are turning to a specific dimension you can set that dimension as a zero and read how much needs to be removed to get the intended dimension.

Thread: Choosing a lathe
29/10/2020 21:28:07

I also didn't know what I would be using the lathe for but I inherited a 10X24 inch Chinese made lathe with a gap bed. Now that I have had it for several years I know what I would use the gap bed for as I did need it for one project. It came with a steady rest which I also have found a use for. Bigger is better in my mind because I can still make little parts on a big lathe but no big parts on a little lathe. With that in mind, space available and how to handle the weight of the lathe getting it to that available space must be considered even before checking your wallet to see if you can afford it.

Thread: Budget CNC
29/10/2020 21:22:06

Does the CNC he desires need to be able to cut metal? Would a wood cutting CNC machine satisfy him for a while? How about helping him build a CNC router? With that approach he/you can save some money and have a better understanding what it takes to make a CNC machine. Knowing that will set him up to be better able to understand and use a CNC mill. Here are a couple videos on making one.

Do it yourself CNC

$500 home built CNC router

Thread: Overrating a power supply for a DC motor?
23/10/2020 11:46:10
Posted by Hollowpoint on 22/10/2020 22:08:22:

Need some help guys.

I have a small DC motor I want to use on a project. The motor is 24v 200w and "rated" 11 amps.

I suspect the amp rating is at full speed with no load but not sure? Obviously if that is correct with heavy load it will draw more amps.

How do I choose the correct amp power supply? Do I need to go bigger? how much bigger?

How fat is your wallet? Ideally you want a power supply that can produce 24 volts (motor is rated for that voltage) and infinite amperage. That would keep the voltage constant over any load possible. Now you know that the motor can only draw 11 amps maximum so in theory a power supply that can produce 24 volts and 11 amps should be sufficient but in the real world, as the power supply approaches that maximum load the voltage drops. I'd probably be looking for a supply that could produce twice the rated amperage as that should be fully capable of maintaining the voltage at 24V but then I would compare that supply cost to how my wallet looks and think about a compromise. How often would I need that full power? What will be the consequences if the voltage drops a bit under full load?

Thread: Milling spindle motor - AC or DC
01/10/2020 12:10:56

Speed control technology has rapidly advanced such that what is available for speed control for DC motors now wasn't available when the book was written. What was normally achieved by changing pulleys can now be adjusted with the turn of a potentiometer. The advent of technology to create brushless motors with high performance is quite new also, again probably since the book was written. It is also possible that the author has a bias.

Thread: Cheap Milling Vice Question
27/09/2020 11:59:10

Put an endmill or fly cutter into the spindle of your mini mill and measure the distance to the bed. Now subtract the height of the vice you mentioned from that to see what size of material you can fit into the remaining space. You may decide that the swivel base will take up too much of the space available for the amount of times you will benefit from the swivel.

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