# Alterations to a BV20 Lathe.



## Rareone

Hi fellas. this is my first post so I hope I am in the right part. Firstly, let me say thanks to you all  for a great web site and for allowing me to become a part of it. I will in the near future up date my personal folio so then at least you can find out a bit about me. My reason for this post is to ask, if anybody can tell me if it is possible to install change gears on the BV20 Lathe? I read a recent post that had a photo and discussion relating to a BV20 Lathe that had two(2) change gears fitted to the front of the Headstock. If I could source the change gears and levers maybe I could install them to my lathe. As it is If I want to change speed I have to get a spanner and change the drive gears. (Pain) Any information would be appreciated. Thanks


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## n4zou

The easiest solution would be an E-LeadScrew.

E-LeadScrew · Lathe Electronic Lead Screw R&D


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## Omnimill

The BV20 has a 6 speed gearbox, manual for it here:

http://www.axminster.co.uk/downloads/bv20m_manual.pdf

Picture of a typical version:

http://www.model-engineer.co.uk/sites/7/images/member_albums/46033/lathe arrives.jpg

What's happened to your gears and levers?


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## Rareone

Thank you n4zou and omnimill for your response. My lathe BV20 has never had any change gears. Maybe when the lathes were sold  here in Australia they were manufactured without the change gears. As I said " I only recently saw that the BV20 was available with these gears fitted." My lathe is just blank on the panel where the levers are positioned. If I could source the gears and levers I am sure that it would not be a major job to fit them.


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## Rareone

Hey omnimill just had a look at your links and would like to let you know that the photo of the lathe is  the same as mine only mine is painted Green. The manual shows the same lathe. The only difference is my lathe has a maximum length of workpiece of 550mm. There is a shorter version of the BV20 that only takes a 400mm workpiece. Thank you for the links. Graham.


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## Omnimill

In that case I'm guessing some models of the BV20 use a variable speed motor instead? Strange as it's a nice little Lathe as it was.


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## velocette

Rareone said:


> Thank you n4zou and omnimill for your response. My lathe BV20 has never had any change gears. Maybe when the lathes were sold  here in Australia they were manufactured without the change gears. As I said " I only recently saw that the BV20 was available with these gears fitted." My lathe is just blank on the panel where the levers are positioned. If I could source the gears and levers I am sure that it would not be a major job to fit them.



Hi Rareone

The BV20 Lathe comes in several models With  a Six Speed Gearbox or a Six Speed belt drive.

Which model do you have. 

Would you please point us to the Forum you mention in your original posting

Eric


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## Simon0362

Rareone said:


> Thank you n4zou and omnimill for your response. My lathe BV20 has never had any change gears. Maybe when the lathes were sold  here in Australia they were manufactured without the change gears. As I said " I only recently saw that the BV20 was available with these gears fitted." My lathe is just blank on the panel where the levers are positioned. If I could source the gears and levers I am sure that it would not be a major job to fit them.



Rareone,
Can you contact me by PM - I may be able to help.

Simon


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## Rareone

Hello Eric. My lathe is the 6 speed belt drive. Would like to convert it to a change gear to give an easy selection for the chuck speed. I am not  worried about the lead screw speed as that can be changed by the drive gears. I cannot remember where I saw the original setup but Omnimill has forwarded a link to the Manual for a gear change BV20M. Graham


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## Rareone

The variable speed motor might be the easiest way to go, but then I wonder what happens to the torque of the motor.


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## RichD

RareOne,
I have a Harbor Freight 9x20. There is a Yahoo Group for the 9x20 lathe... http://groups.yahoo.com/group/9x20Lathe/?yguid=78923251
They cover just about everything you'd want to know about your lathe.
Regards,
Rich


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## velocette

Rareone said:


> The variable speed motor might be the easiest way to go, but then I wonder what happens to the torque of the motor.



Hi Rareone

This is probably the best option as the spindle is unlikely to be machined to fit gears.

My preference is for 180 volt DC motor and 230 volt AC to DC Convertor and Speed control.

The DC advantage is that the Torque does not fall sharply as the speed decreases.

My own setup is BV25BL lathe with six speed gearbox and DC motor and Control a very similar lathe to yours.

Normaly I select the gear for the diameter and approximate surface speed required  

and then fine tune the speed with the control.

Being a DC motor fanatic my views are very biased with a lathe, milling machine on DC  With power feeds on DC, 

Also two drill presses. Have a peek at my postings on HMEM

Eric


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## Rareone

Thanks for all of the feedback fellers. I think I will go with and research more info on what Eric has said. I will see what is available in Australia. Thanks to you all . Graham


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## Rareone

Thanks for all of the responses fellas. I am going to research the possibility of using a DC motor and electronic speed variation.


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## Ryan

We also have a BV 20, belt drive but one with the tiny milling machine attached which we took off.

Did you come up with a solution to the  speed control?  I'd also like to install a QCTP  & 4jaw chuck.  have you done those modifications?


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## glados116

Hello all. I have recently acquired a Bengbu BV-20 lathe. Unfortunately the guy who gave it did not have any manual to give me. I tried the provided link in the forum but it seems the file does not exist any more. Anyone who has the manual and is willing to share it? I need to check how to read how change speed of revolution.
Thanks in advance.


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## Omnimill

Have a google, here's one:

http://www.cnc.info.pl//files/dtr_tokarka_bv_20_126.pdf


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## Rareone

Hi Glados116.  I can email you the manual if you like. It is not much of a read but better than nothing. Try this, :- Just type into your browser "BV 20 Owners Manual" search and then go through the sites. Let me know how you go. Hope this helps. Graham


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## glados116

The link provided is for a Warco lathe. Mine is a Chinese model:
BV-20 Bengbu Machine Tool Co.
Also the photo of BV20-1 is not quite like mine. The reason I am looking for a manual is that I have no idea how to regulate lathe speed. I don't even know the revolving speed. The BV20-1 shows some levers above the start-stop buttons, which are not present in my lathe.


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## glados116

Rareone said:


> Hi Glados116.  I can email you the manual if you like. It is not much of a read but better than nothing. Try this, :- Just type into your browser "BV 20 Owners Manual" search and then go through the sites. Let me know how you go. Hope this helps. Graham



Yes please if the manual is for the BV20 chinese lathe. My email is [email protected].


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## La Roculiere

Without a photo of the original poster's lathe, it makes it somewhat difficult to give precise information.  There is a plethora of 9 x 20 variants available - all slightly different to one another.  To clear up one thing, though, the photo in omnimill's initial reply is actually MY lathe.  The picture has somehow been lifted from my album!  I'd recognise my garage/workshop anywhere!  The lathe is actually marketed as a BL-200 bench lathe and I purchased it locally (relatively!) from Worken.fr in Caen, France about 3 years ago.  Cost about 900 then including a 4-jaw chuck and full set of change gears and fixed steady etc.  It'll cut metric and imperial threads with the supplied gears, when fitted in accordance with the table in the manual.  My only criticisms would be that the slowest selectable spindle speed of 170 rpm is really too fast for screw threading and the cross slide lacks tee slots.  I've removed the four position toolpost and replaced it with a QCTP imported from RDG in the UK.  Vast improvement!

John


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## Omnimill

The very first job I did on my BV20 was to make the smallest possible pulley to reduce the speed on mine. Bottom speed is now 100 rpm which is much better for thread cutting.


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## goldstar31

In the Home Model Engineering Clearing House forum, there was quite a bit of correspondence on the 918/920 and how the lathe was altered to reduce the 130rpm( British version) and how to cut left hand threads. I described how I had fitted a steel subtable to accept Myford and similar accessories. 
I'm still using them.

Cheers

Norman


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