Newbie needs advice about a lathe

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Old Guy

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The lathe in question is my recently purchased second hand but very young Chester DB super 10 long bed which I have done very little work on other to try to get a handle on it's use by trying to do a few passes on a length of round bar that I happened to have, the outcome of which was pretty poor in it's finish this could be due to the type of metal the bar was made of but this doesn't matter at the moment as i do intend to purchase some better steel for any future attempts.
There are a couple of things that have got me concerned about the lathe

1) It has variable speed control by a knob on the head stock but when the knob is fully off the chuck still rotates at about 40 RPM as soon as the power is turned on so the only way to stop it is to turn the power off, Would this be normal on these types of lathe

2) When running it does seem quite noisy, not sure if this is normal

3) When you turn the chuck by hand there does seem to be the feel of a slight rumble from the head bearings as if maybe the shaft might be over tightened on the bearings

I have put a DTI on the chuck and there seems to be little or no run out on it so you would think the bearings should be in good order any advice would be much appreciated from our much more experienced members
 

RM-MN

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1. My Harbor Freight mini lathe wants to keep turning when I turn the knob all the way down. I think that is because the potentiometer does not have infinite resistance. The power switch comes closer to infinite.

2. The gears that allow changes in the speed of the lead screw are not perfect on my lathe and make noise. Try putting the leadscrew in neutral and see if the noise goes away.

3. The "rumble" you feel may be related to the gears mentioned in item 2.
 

Old Guy

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1. My Harbor Freight mini lathe wants to keep turning when I turn the knob all the way down. I think that is because the potentiometer does not have infinite resistance. The power switch comes closer to infinite.

2. The gears that allow changes in the speed of the lead screw are not perfect on my lathe and make noise. Try putting the leadscrew in neutral and see if the noise goes away.

3. The "rumble" you feel may be related to the gears mentioned in item 2.
Thanks RM-MN for that speedy reply I'm glad to hear the slow running is probably normal for these machines I will make sure that the lead screw gears are in neutral next time I give it a whirl and see if it makes a difference but I fear that it is in neutral because neither of the drives are turning.
The lathe is very similar to the one used by Blondie hacks but where hers has two lead screw knobs this one has three and two drive shafts where I believe hers has one combined shaft I could well be wrong
I think I might post a short video of the lathe running and see what people think and thanks again
 

trlvn

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Thanks RM-MN for that speedy reply I'm glad to hear the slow running is probably normal for these machines I will make sure that the lead screw gears are in neutral next time I give it a whirl and see if it makes a difference but I fear that it is in neutral because neither of the drives are turning.
The lathe is very similar to the one used by Blondie hacks but where hers has two lead screw knobs this one has three and two drive shafts where I believe hers has one combined shaft I could well be wrong
I think I might post a short video of the lathe running and see what people think and thanks again
Blondihacks uses a Precision Matthews PM1022. It is almost identical to my Busybee CX706 (Canada). Grizzly in the US also sells virtually the same machine by another name. As you say, yours is similar but has separate feed v. threading drive rods. I like yours!

You may be able to find Youtube videos that help you gauge whether yours is truly noisy or not. I'm guessing that you are just hearing the gear train noise. Gears need to be set with a little bit of clearance--they can be extra noisy if set too tight.

Switching between High/Med/Low feed speeds might help you isolate whether the noise is coming from the gears, as well.

Re surface finish, tell us more details about cuts you were trying. Carbide insert, brazed carbide or HSS tool? Workpiece diameter? RPM and feed settings? Pictures of the tool and result?

Craig
 

Old Guy

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Blondihacks uses a Precision Matthews PM1022. It is almost identical to my Busybee CX706 (Canada). Grizzly in the US also sells virtually the same machine by another name. As you say, yours is similar but has separate feed v. threading drive rods. I like yours!

You may be able to find Youtube videos that help you gauge whether yours is truly noisy or not. I'm guessing that you are just hearing the gear train noise. Gears need to be set with a little bit of clearance--they can be extra noisy if set too tight.

Switching between High/Med/Low feed speeds might help you isolate whether the noise is coming from the gears, as well.

Re surface finish, tell us more details about cuts you were trying. Carbide insert, brazed carbide or HSS tool? Workpiece diameter? RPM and feed settings? Pictures of the tool and result?

Craig
Hello Craig Thanks for your input that is a great idea about the you tube vids to asses the noise levels and I will try the switching as well
I first tried a carbide insert tool that was already fitted in the holder and with different depths of cut but I can't say what the actual depths were as I'm not used to the measurements on the hand wheel yet the lathe didn't have any trouble driving the piece and tried hand turning and machine feed but the results were similar,I believe the carbide prefer a heavy cut for the best finish which is what I had tried to achieve.
I bought a set of HSS tools to try and picked one to try which might well have been the wrong one but I was only experimenting.I did all this between centres
I will take some pics and post them for people to asses
Thanks again
 

trlvn

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Well I took a few pictures and a short video but being the pc numpty I am I can't work out how to post them any advise gratefully received
As a start, could you tell us what device you used to take the pictures and record the video? Have you transferred these files to a personal computer (what operating system). Have you tried using the "Attach files" and/or "Upload Video" buttons to get the files onto this web site? Is so, was there a message indicating a failure? What, exactly, did it say?

Craig
 

Old Guy

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Hi Craig
Yes I recorded it on my iPhone and put it on my mac so it is on the same computer I use to do these posts.
so I click the upload video tab and get the window up with launch menu in the top box but I can't find how to get to my photo library, do I have to go to my pictures first and press share before I do the upload tab its all very confusing to me, and now I seem to have changed the font somehow even though I haven't touched anything
 

trlvn

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Hi Craig
Yes I recorded it on my iPhone and put it on my mac so it is on the same computer I use to do these posts.
so I click the upload video tab and get the window up with launch menu in the top box but I can't find how to get to my photo library, do I have to go to my pictures first and press share before I do the upload tab its all very confusing to me, and now I seem to have changed the font somehow even though I haven't touched anything

Let's start with the photos. From your description, it seems you are using the Photos application from Apple. You were on the right track by opening the picture you want to upload here and then selecting the "Export 1 Photo..." command from Export submenu on the File menu. That should bring up a dialog box much like this:

Photos export dialog.png


There are lots of valid ways to do things, but I like to change the "File Name" option to "Sequential" and then fill in something in the "Sequential Prefix" field. In this case, I've entered 'Test export' but you can put in something meaningful to you. After doing that, then click the blue "Export" button. That will bring up the following standard file picker dialog, like this:

Photos export.png

This let's you choose where to put the file that you are exporting. A nice simple choice is the one I've circled in red, the "Desktop". First click that entry (Desktop) and then click the blue Export button. A notification message should appear momentarily in the upper right of your screen confirming that the file has been exported.

Now you need to switch the browser window for this website and use "Attach files" to upload your photo to a new message or reply, like follows:

attach files dialog.png


In this dialog, you again click "Desktop" since that's where you put the file to be uploaded. In the above, you can see that I have clicked on the file "Test export - 1" since that is the file name I gave to the photo.

Hope this helps. There could be minor differences in appearance if we're not running the exact same version of MacOS (which is pretty likely).

Craig
 

Old Guy

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Hi Craig
Thanks for that brilliant description I will work my way through it tomorrow when I have a clearer head and with a bit of luck you might get to see how not to machine a piece of bar on a lathe and how noisy you think it is
Thanks again John
 

RM-MN

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Hi Craig
Yes I recorded it on my iPhone and put it on my mac so it is on the same computer I use to do these posts.
so I click the upload video tab and get the window up with launch menu in the top box but I can't find how to get to my photo library, do I have to go to my pictures first and press share before I do the upload tab its all very confusing to me, and now I seem to have changed the font somehow even though I haven't touched anything

The code to make your text italicized is CTRL I, which probably happened when you attempted to type the capital I and accidentally bumped the CTRL key when you hit the shift key as the CTRL key is directly below the shift key.
 
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let's go back to the original question of why the spindle turns at a low RPM - this is important - there is a huge difference between "off" and "zero RPM" to a controller. Off means it is unpowered. Zero RPM means that the motor is fully energized and will resist (to the best of its ability) any attempt to turn it. All real lathes have a drum switch or a push button for start/stop. when you want the lathe to stop, you press "stop", when you want it to go, you press "start". Generally you set the RPM for the SFM (surface feet per minute) you want based on the material and the tooling and you start and stop the lathe as required.

The low RPM with the knob at minimum speed is a safety feature so you don't burn out the motor.
 

Old Guy

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wwwwwwww
The code to make your text italicized is CTRL I, which probably happened when you attempted to type the capital I and accidentally bumped the CTRL key when you hit the shift key as the CTRL key is directly below the shift key.
Thanks I daren't even start to tell you what happened when I tried to post the pics again I don't seem to get the windows shown by Craig but it was a REAL mess up I had to call in my computer expert to try to sort it out ie the Missus she managed to get the screen back again but even she couldn't upload the pics to the forum
Let's start with the photos. From your description, it seems you are using the Photos application from Apple. You were on the right track by opening the picture you want to upload here and then selecting the "Export 1 Photo..." command from Export submenu on the File menu. That should bring up a dialog box much like this:

View attachment 139925

There are lots of valid ways to do things, but I like to change the "File Name" option to "Sequential" and then fill in something in the "Sequential Prefix" field. In this case, I've entered 'Test export' but you can put in something meaningful to you. After doing that, then click the blue "Export" button. That will bring up the following standard file picker dialog, like this:

View attachment 139924
This let's you choose where to put the file that you are exporting. A nice simple choice is the one I've circled in red, the "Desktop". First click that entry (Desktop) and then click the blue Export button. A notification message should appear momentarily in the upper right of your screen confirming that the file has been exported.

Now you need to switch the browser window for this website and use "Attach files" to upload your photo to a new message or reply, like follows:

View attachment 139926

In this dialog, you again click "Desktop" since that's where you put the file to be uploaded. In the above, you can see that I have clicked on the file "Test export - 1" since that is the file name I gave to the photo.

Hope this helps. There could be minor differences in appearance if we're not running the exact same version of MacOS (which is pretty likely).

Craig
Sorry Craig I don't seem to get any of those windows on my mac when my wife tried the closest was that a pic seemed to be downloading but then it came up error file too big so Im back to square one
 

Old Guy

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let's go back to the original question of why the spindle turns at a low RPM - this is important - there is a huge difference between "off" and "zero RPM" to a controller. Off means it is unpowered. Zero RPM means that the motor is fully energized and will resist (to the best of its ability) any attempt to turn it. All real lathes have a drum switch or a push button for start/stop. when you want the lathe to stop, you press "stop", when you want it to go, you press "start". Generally you set the RPM for the SFM (surface feet per minute) you want based on the material and the tooling and you start and stop the lathe as required.

The low RPM with the knob at minimum speed is a safety feature so you don't burn out the motor.
Thanks for that info I had assumed wrongly of course that the speed knob controlled the power to the motor but obviously not, the problem is that every time you stop it you then have to faff with the covered locked ON OFF switch to get it going again and if you use the forward stop reverse switch the same thing happens there seems to be no simple start stop with it at all
 

djc

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There is a manual for the machine available at: Our Manual Library - Chester Hobby Store if you have not already found it. It contains a wiring diagram which explains the control logic.

If you really do want to use the speed control for switching it on and off, change the potentiometer for a 5 wire, switched version of the same resistance and characteristic (linear/log) as the existing one. You will need to wire the switched part in series with the other interlocks on the machine (chuck guard, E-stop, etc.) as they will be a low voltage, low current control circuit.
 

trlvn

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Thanks I daren't even start to tell you what happened when I tried to post the pics again I don't seem to get the windows shown by Craig but it was a REAL mess up I had to call in my computer expert to try to sort it out ie the Missus she managed to get the screen back again but even she couldn't upload the pics to the forum

Sorry Craig I don't seem to get any of those windows on my mac when my wife tried the closest was that a pic seemed to be downloading but then it came up error file too big so Im back to square one

If the homemodelenginemachinist.com website gave you the "file too big" error message, you were actually VERY close to the finish line! And we can fix it! When you export the photo from the Photos application, we have to do an extra step or two.

When you have brought up the photo that you wish to export and selected the "Export 1 Photo..." command from Export submenu on the File menu, you should see the following dialog (same as before):

Photos export dialog 2.png

This time, however, click the little control circled in the screenshot above. The dialog will expand to offer some more options as shown in the following screenshot. (Clicking the control again will toggle the dialog between hiding and showing the additional options. This technique is commonly used in many Mac applications.)

Photos export dialog 4.png

Notice above that we now have a "Size" option for the file we're trying to export. Choose either "Medium" or "Large". As before, select "File Name: Sequential" and type something meaningful to you in the "Sequential Prefix" field. Then continue on as before clicking the blue Export button and whatnot.

The following photo was exported with the "Medium" size option:

Test export - 1 (2).jpeg


Craig
 

trlvn

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To others, what is the file size limit for this forum? I'm able to upload a 4.4 MB (see following). OldGuy apparently got an error message but his device might be creating bigger photo files than my 3 year old iPhone.

IMG_4705.JPG


Craig
 

willray

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let's go back to the original question of why the spindle turns at a low RPM - this is important - there is a huge difference between "off" and "zero RPM" to a controller. Off means it is unpowered. Zero RPM means that the motor is fully energized and will resist (to the best of its ability) any attempt to turn it.

With all due respect, no.

Unless you are using some kind of servo (or I suppose stepper) drive system, "zero RPM" to the controller means "put out zero power". It does nothing to lock or restrict rotation of the rotor. There undoubtedly are servo-drive lathe spindles, but I suspect very, very few of us are using them.

The real origin of the confusion is that in these (and similar) lathes, the "speed knob" (potentiometer, whatever) is a speed knob, it's not an off switch. You want "off", you turn the motor off. You want slow, you turn the speed knob to slow.


All real lathes have a drum switch or a push button for start/stop. when you want the lathe to stop, you press "stop", when you want it to go, you press "start".

The low RPM with the knob at minimum speed is a safety feature so you don't burn out the motor.

Again I beg to differ. On all the real lathes I've met, when you want the lathe to start, you engage the clutch, and when you want it to stop, you disengage the clutch and engage the brake. The push button "start" switch only spools up the motor, and it won't activate if the clutch is engaged.

Low RPM with the knob at minimum speed is because you presumably want the lathe to turn at minimum speed when you have the knob at minimum speed... It would be kind of silly to have it do otherwise :)
 

willray

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the problem is that every time you stop it you then have to faff with the covered locked ON OFF switch to get it going again and if you use the forward stop reverse switch the same thing happens there seems to be no simple start stop with it at all

A quick look at what I think is your lathe's supposed schematic, and it appears that the Forward/Reverse/0 switch is intended to let you switch the lathe between running (either direction) and stopped, without needing to manipulate the covered/locked Start switch. The instruction manual (if I've got the right one) seems to agree with this.


It looks like the covered "Start" switch is supposed to engage the electronics/brain, and the forward/reverse/0 switch is supposed to engage the motor, if the electronics/brain are engaged.
 

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