Central Machines Mini Mill Will Not Run In High

[vigsgb]

When I have my four inch chuck on my mini lathe the lathe kicks out anytime I try to start it with the lathe in high spindle speed gear.

Anyone know if that setting can be increased so it does not kick out?

Thanks

 

[ProdEng]

Sadly a four inch chuck is probably too heavy for this size of lathe and trying to get the electronics to drive it will destroy the electronics. So the answer is to use the chuck supplied with the machine. If you need more chuck capacity you could use the 4 jaw chuck though that takes a little longer to set up. If you are regularly using material bigger than one inch you should consider a bigger lathe, the 7x is good for small parts but lacks the power or strength for bigger things.

Jan

 

[Anko]

You can try using the reversible jaws, they will allow you to chuck bigger diameters, but if you want to run a 4" chuck, in the mini-lathe.com page, in the section of modifications, there is some info about setting up the drive circuit for adjust speed and torque.

Hope to help
Saludos

 

[velocette]

Hi this machine will run with a bigger chuck as there is a spindle conversion available.

You MAY as the choice is yours as I only point to what can be done to improve the situation.

In the Control Box for the motor are several adjustments for motor control
something like this Max Min Acc Torque OL IR .

Acc controls the rate at which the motor accelerates adjusting this can increase the time to accelerate to full speed.

If you have to turn down the speed control to stop the motor then START by turning it up very slowly to accelerate to the required speed.

I can provide you with access to more information Early next week as I am away from my own computer for the weekend.

No guarantees on the accuracy of the info that I can direct you to or any that I have given
yours is the final choice.

Happy hunting I am sure that someone on HMEM can be of greater help than I.

Eric

 

[velocette]

Hi Greg I Have Trawled through the files on my computer and can find nothing that is of any help.

Here is the link to fitting a 100 mm chuck

http://www.toolsandmods.com/lathe/mini-lathe-headstock

What little information I have read there is the attitude that the manufactures will not disclose any information on how to adjust and set up their control boards for this lathe.

However if you go to DC drives made in the USA they are a great source of info.

Try http://www.kbelectronics.com/Variable_Speed_DC_Drives.html

I believe that the KBMM dc controler is fitted to some lathes and mills supplied in the USA

or

http://www.minarik.com

The minarik MM23011C is available at a very reasonable price at

http://www.surpluscenter.com/item.asp?item=11-2269&catname=electric

Eric

 

[Tin Falcon]

This may be a silly question but do you have the pot turned to the low setting you are supposed to turn them on then crank up the speed. .
yes you may need to adjust the pot on the board as well.
Tin

 

[vigsgb]

I did find something that says I can replace the current board for the lathe which is a 250 watt board with a 350 watt board and that will give it the power it needs.

I did look at the circuit for the board and could bypass the cutout circuit but I am not willing to risk not having that safety feature as I think it is important.

One thing I did notice is that the spindle speed does indeed have a very fast start as soon as the machine turns on so that may be tripping the overload circuit. I will try turning the initial speed down by adjusting the speed pot on the board and see if that will work. Otherwise I will run it on low with the 4" chuck.

Thanks for all the information

 

[vigsgb]

This may be a silly question but do you have the pot turned to the low setting you are supposed to turn them on then crank up the speed. .
yes you may need to adjust the pot on the board as well.
Tin

Well I feel pretty silly now... I put the lathe on low and very slowly turned up the speed and it worked.... I guess I was turning the speed up to fast which overloaded the motor... :hDe:

 

[Tin Falcon]

well it was an easy fix. it is amazing what we learn from reading the manual.
and yes the manual on the 7xs are not usually well written.
Tin

 

[Don1966]

There are some boards that have adjustment pots mark acceleration and Deceleration or ACC OR DECC. These pots control how fast the speed is ramped in the controller. If you have these adjustments adjust the ACC clockwise to increase the ramp time on start up, this will limit the torque required. The DECC will control how fast the speed comes to a stop. Hope this helps.

Don