[Morndenkainen]

Well, I recently bought a harbor freight 33686 mill, which is near identical to a G0705. I've used it to make a few things and it's served me pretty well. I know people here tend to blast round column mills, but I really haven't had any issues with my head deflecting or walking. Then again, I don't do "tall" work. It's done wonders on making small ATV parts, small engine parts, brackets, etc. Anyways, the reason I'm posting is because I want to upgrade this mill to ball screws and eventually CNC controls. Right now, I have backlash in the screws that's really annoying to deal with. I understand that by switching to ball screws the table will walk all over the place if it isn't screwed down and am prepared to deal with that for a bit.

Does anyone know what size ball screws it would take to convert this thing? I've looked around a good bit and although I've found several CNC conversions, I haven't seen a good ball screw conversion post.

I'm really hoping to find out what would be the easiest and most effective sizes to use for the conversion.
What diameter? What thread pitch?

[tone1963]

Well, I recently bought a harbor freight 33686 mill, which is near identical to a G0705. I've used it to make a few things and it's served me pretty well. I know people here tend to blast round column mills, but I really haven't had any issues with my head deflecting or walking. Then again, I don't do "tall" work. It's done wonders on making small ATV parts, small engine parts, brackets, etc. Anyways, the reason I'm posting is because I want to upgrade this mill to ball screws and eventually CNC controls. Right now, I have backlash in the screws that's really annoying to deal with. I understand that by switching to ball screws the table will walk all over the place if it isn't screwed down and am prepared to deal with that for a bit.

Does anyone know what size ball screws it would take to convert this thing? I've looked around a good bit and although I've found several CNC conversions, I haven't seen a good ball screw conversion post.

I'm really hoping to find out what would be the easiest and most effective sizes to use for the conversion.
What diameter? What thread pitch?

I just purchased a G0705 and want to do the same thing with regard to play in screws I have been a machinists for 40 years you just have to always go in one direction if you pass your number go back one turn and try again
as for size of screw
I think 5/8 is ok also for some idea flashcutcnc.com or check out YouTube

[109jb]

One thing to be aware of with regard to ballscrews is that they can be back-fed whereas the acme screws can't for all intents and purposes. What this means it that if you want to have an axis stay put, you will want to lock it. It would be good to also lock the screw from rotation s well as the gib locks.

As for what size ballscrews, a 5/8" (16mm) ballscrew is enough from calculations, but many would go to a 3/4" (20mm) ballscrew. Personally I'd do 5/8" (16mm) unless the price of the 3/4" (20mm) are very close. The chinese ballscrews off of e-bay are a good choice, but McMaster Carr also sells Thompson rolled ballscrews. The chinese ones you can get pre-machined on the ends. The McMaster Carr ones are just ballscrew stock cut to length.

It isn't your exact mill, but I did a smaller round column Harbor Freight mill and you can see the thread at the link below.

http://www.cnczone.com/forums/bencht...cnc-forum.html

Good luck

[Morndenkainen]

One thing to be aware of with regard to ballscrews is that they can be back-fed whereas the acme screws can't for all intents and purposes. What this means it that if you want to have an axis stay put, you will want to lock it. It would be good to also lock the screw from rotation s well as the gib locks.

As for what size ballscrews, a 5/8" (16mm) ballscrew is enough from calculations, but many would go to a 3/4" (20mm) ballscrew. Personally I'd do 5/8" (16mm) unless the price of the 3/4" (20mm) are very close. The chinese ballscrews off of e-bay are a good choice, but McMaster Carr also sells Thompson rolled ballscrews. The chinese ones you can get pre-machined on the ends. The McMaster Carr ones are just ballscrew stock cut to length.

It isn't your exact mill, but I did a smaller round column Harbor Freight mill and you can see the thread at the link below.

http://www.cnczone.com/forums/bencht...cnc-forum.html

Good luck

I saw that post and I mentioned being aware of the back-feed/walking. What I was really concerned about was the size of the ballscrews themselves. I've looked at several posts regarding changing the round column mills over, but no one ever mentions what "size" ball screws they are using. There's just never any info regarding what diameter or what length they use. It's rather funny actually, everyone's willing to show you how they do it. No one ever bothers to tell you what they've used to do it. Bearings for example. Everyone says what kind of bearing they used, no one ever shows how they set up their bearing block or gives a size.

With regards to the length on the ball screws, I have a 29" (736mm) table, roughly 27" (685mm) under the table inside edge to edge. When I buy the ballscrew for that axis, do I need to buy like a 36" screw and turn it down on my lathe? Or would a 27" (685mm) screw be sufficient? Or do I need to order something bigger like a 32" (810mm) screw with the ends machined? Ideally, I'd really like to only have to buy one of these.. I've seen several screws that come with the end blocks and bearings and a kit seems more cost effective if I can find one the right size.

I plan on using the 1605 size screws for my conversion. I really don't see the need for a larger screw and know I'm limited on space.


Tone, I do that most of the time, It's become a habit. I guess I'm just getting lazy. :P Besides, once I convert to CNC, I want as little backlash as possible, HF mills are noted for their incredible accuracy and tight tolerances... LOL!

[tone1963]

I saw that post and I mentioned being aware of the back-feed/walking. What I was really concerned about was the size of the ballscrews themselves. I've looked at several posts regarding changing the round column mills over, but no one ever mentions what "size" ball screws they are using. There's just never any info regarding what diameter or what length they use. It's rather funny actually, everyone's willing to show you how they do it. No one ever bothers to tell you what they've used to do it. Bearings for example. Everyone says what kind of bearing they used, no one ever shows how they set up their bearing block or gives a size.

With regards to the length on the ball screws, I have a 29" (736mm) table, roughly 27" (685mm) under the table inside edge to edge. When I buy the ballscrew for that axis, do I need to buy like a 36" screw and turn it down on my lathe? Or would a 27" (685mm) screw be sufficient? Or do I need to order something bigger like a 32" (810mm) screw with the ends machined? Ideally, I'd really like to only have to buy one of these.. I've seen several screws that come with the end blocks and bearings and a kit seems more cost effective if I can find one the right size.

I plan on using the 1605 size screws for my conversion. I really don't see the need for a larger screw and know I'm limited on space.


Tone, I do that most of the time, It's become a habit. I guess I'm just getting lazy. :P Besides, once I convert to CNC, I want as little backlash as possible, HF mills are noted for their incredible accuracy and tight tolerances... LOL!

https://www.youtube.com/watch?v=gyaHoJc1I9s

*

*

http://www.flashcutcnc.com/sites/default/files/hardware/corresponding-reference/URK%20Manual%2003-20-2012%20%282%29.pdf

Check out these I am planning to use acme screws and change out later also found motorshttps://www.automationtechnologiesinc.com/products-page/stepper-nema34-3-axis-kits/nema-34-stepper-motors-3-4-axis-kit-5/ let me know what you think

[tone1963]

https://www.youtube.com/watch?v=gyaHoJc1I9s

*

*

http://www.flashcutcnc.com/sites/default/files/hardware/corresponding-reference/URK%20Manual%2003-20-2012%20%282%29.pdf

Check out these I am planning to use acme screws and change out later also found motorshttps://www.automationtechnologiesinc.com/products-page/stepper-nema34-3-axis-kits/nema-34-stepper-motors-3-4-axis-kit-5/ let me know what you think

This maybe

[tone1963]

This maybe

Let me know how to make a hyper link out of Web address

[Morndenkainen]

Let me know how to make a hyper link out of Web address

Would if I knew how...

That kit looks pretty nice but the price on it is a bit high. The same stuff can be had off e-bay for much less and machined on the mill. Which is part of why I bought the mill. I mean, it looks like nothing more than thick wall 4"x1-1/2" aluminum rectangle channel. :P One thing I DID like the looks of though were the ball screw extensions. Using a couple of those would greatly simplify the installation of the balls crews as I could make the extensions out of aluminum or mild steel on my lathe or a rotary indexer if I had to. That would also simplify the choice between bearings and once the fit is accurate, the ball screw could be epoxied into the extensions or removed and welded. (using mild steel) With that thought, I'm probably going to get my ball screws ordered as soon as this ridiculous 2 week long chinese new year thing is over and they get back to work.. :P The upside is that with the decision to use the extensions, I don't have to worry about machining the ball screws and can order shorter and higher quality parts since they'll be cheaper due to size.

I'd seen the video for the flashcut conversion, but not the pdf. That was pretty helpful.

Ebay is full of Nema kits, honestly I'll probably piecemeal one together though so I can be sure it comes with a USB input instead of a parallel port.

Ended up buying a set of ball screws on E-bay. Found a 1605 size that's 350mm long for the Y axis, and one that's 700mm long for the X axis. I plan on machining some extenders to hold the screws in the factory bearing blocks.. They're on the slow boat from china in the middle of chinese new years. Ebay estimates delivery at 20+ days out... We shall see...

[Stigoe]

Let me know how to make a hyper link out of Web address

Use "url=<address>" in square brackets (without the "" and <>), the text you want in the link and finish with "/url" in square brackets, or if you're in the adcanced editor, I think you have a tick box for making urls into links.

"Square bracket start" url=http://www.flashcutcnc.com/sites/default/files/hardware/corresponding-reference/URK%20Manual%2003-20-2012%20%282%29.pdf "square bracket end" A pdf file "square bracket start" /url "square bracket end" turns into A pdf file

[tone1963]

Use "url=<address>" in square brackets (without the "" and <>), the text you want in the link and finish with "/url" in square brackets, or if you're in the adcanced editor, I think you have a tick box for making urls into links.

"Square bracket start" url=http://www.flashcutcnc.com/sites/default/files/hardware/corresponding-reference/URK%20Manual%2003-20-2012%20%282%29.pdf "square bracket end" A pdf file "square bracket start" /url "square bracket end" turns into A pdf file

Thanks Stigoe will try it

Morndenkaine
I have also seen one guy hard turn end of
ball screws 1/2 inch to a dia. and
make the adapter with a counter bore and
put set screws in .

[Morndenkainen]

Ive got a few days before the ball screws arrive. Once they do, I'll get to work and post some pics I hope.

[tone1963]

Ive got a few days before the ball screws arrive. Once they do, I'll get to work and post some pics I hope.




Take a look at this machine crude but works well with acme
screws

http://youtu.be/374ELEb3ADQ

[shepdog]

subscribed...my Craftex B1977 is a clone I think, so post lots of pics as you go!

[Morndenkainen]

Attachment 269800Attachment 269802Attachment 269808

Ok, so I've got the ball screws ordered. While waiting for my ball screws to arrive, I went ahead and bought a cheap 12" DRO off of e-bay. Perhaps it was the beer that made me click on the buy it now, who knows? Anyways, being stuck inside the house with nothing else to do due to the weather, the DRO was really easy to install on the mill. I was surprised at how easy the casting of the mill was to drill and tap. After playing around with the DRO on the Y axis, I can acually put numbers to how far off the mill was when you change directions. You have to turn the handle nearly 0.02" before you see any movement when you reverse direction on the mill. To me, that seems like a pretty big number. I found a seller on e-bay who had a good deal on the DRO's. His prices were fairly low and he's got a bundled deal where you get 10% off. So anyways, I've ordered a 6" for the Z-axis movement, and a 24" for the X-axis movement. Be aware, that these things are actually a bit longer than the advertised size. The 12" DRO was almost 16.5" long overall. Means you actually get 12" of travel.

The DRO gauge itself is magnetic so I just stuck it to the belt cover until I get the other 2 DRO's in and mount em to a nice little plate. The scales themselves are USB, so perhaps there's a way to integrate them into a better display in the future? Here's a link to the E-bay auction for the scales I bought. Not horribly pricey, and quite a worthwhile upgrade, even if done only one axis at a time.

6" Digital DRO Quill Table Readout Scale for Bridgeport | eBay

Even with my limited experience, installation was pretty easy, I drilled two holes on the bottom casting where I mounted the DRO scale, and then one hole on the back corner of the table, where I used an L-bracket to run an aluminum strip down to the DRO slide. 3 holes in the machine, drilled and tapped in 10-24. I have never tapped cast iron and was a little nervous about breaking a tap off in my machine, but with plenty of WD-40 and taking it easy I had no issues. Worst part was cutting the aluminum strip, the squealing was horrendous.. Note, It's important to keep the scale level so that it doesn't bind up. To do that, I tightened down the screw on the table first to set the height of the slider and finger tightened the scale bar to the side. Then I ran the table all the way to one end of it's travel, gave that end of the scale bar a jiggle and tightened it down snug. Then, I ran the table all the way to the other end of it's travel, gave that end of the scale bar a jiggle, and went ahead and tightened that end down. Then I ran it back the other way yet again, made sure there was no binding along the travel, and tightened down the scale bar for good. That's the entire install process summed up.

I'm still waiting on the ball screws. One shipped a few days ago. The other hasn't been marked as shipped yet. Gotta love the slow boat from China...

[louieatienza]

Attachment 269800Attachment 269802Attachment 269808

Ok, so I've got the ball screws ordered. While waiting for my ball screws to arrive, I went ahead and bought a cheap 12" DRO off of e-bay. Perhaps it was the beer that made me click on the buy it now, who knows? Anyways, being stuck inside the house with nothing else to do due to the weather, the DRO was really easy to install on the mill. I was surprised at how easy the casting of the mill was to drill and tap. After playing around with the DRO on the Y axis, I can acually put numbers to how far off the mill was when you change directions. You have to turn the handle nearly 0.02" before you see any movement when you reverse direction on the mill. To me, that seems like a pretty big number. I found a seller on e-bay who had a good deal on the DRO's. His prices were fairly low and he's got a bundled deal where you get 10% off. So anyways, I've ordered a 6" for the Z-axis movement, and a 24" for the X-axis movement. Be aware, that these things are actually a bit longer than the advertised size. The 12" DRO was almost 16.5" long overall. Means you actually get 12" of travel.

The DRO gauge itself is magnetic so I just stuck it to the belt cover until I get the other 2 DRO's in and mount em to a nice little plate. The scales themselves are USB, so perhaps there's a way to integrate them into a better display in the future? Here's a link to the E-bay auction for the scales I bought. Not horribly pricey, and quite a worthwhile upgrade, even if done only one axis at a time.

6" Digital DRO Quill Table Readout Scale for Bridgeport | eBay

Even with my limited experience, installation was pretty easy, I drilled two holes on the bottom casting where I mounted the DRO scale, and then one hole on the back corner of the table, where I used an L-bracket to run an aluminum strip down to the DRO slide. 3 holes in the machine, drilled and tapped in 10-24. I have never tapped cast iron and was a little nervous about breaking a tap off in my machine, but with plenty of WD-40 and taking it easy I had no issues. Worst part was cutting the aluminum strip, the squealing was horrendous.. Note, It's important to keep the scale level so that it doesn't bind up. To do that, I tightened down the screw on the table first to set the height of the slider and finger tightened the scale bar to the side. Then I ran the table all the way to one end of it's travel, gave that end of the scale bar a jiggle and tightened it down snug. Then, I ran the table all the way to the other end of it's travel, gave that end of the scale bar a jiggle, and went ahead and tightened that end down. Then I ran it back the other way yet again, made sure there was no binding along the travel, and tightened down the scale bar for good. That's the entire install process summed up.

I'm still waiting on the ball screws. One shipped a few days ago. The other hasn't been marked as shipped yet. Gotta love the slow boat from China...

Cool... Hope your ballscrews are not stuck in port with the strike going on...

[tone1963]

Cool... Hope your ballscrews are not stuck in port with the strike going on...

I have a i gauge DRO just like the one that you are installing the only thing I do not like about it is that it takes a while for it to catch up when you are moving it other than that it is better than nothing I have it mounted on a Harding clone

[Morndenkainen]

Attachment 270642Attachment 270644Attachment 270646Attachment 270648Attachment 270650Attachment 270652Attachment 270654Attachment 270656Attachment 270658Attachment 270660Attachment 270662Attachment 270664Attachment 270666

Well, as you can see there's been a bit going on. My X and Z axis DRO's finally arrived and were installed. I tried to keep everything looking fairly clean as far as the install goes so I re-used the original cover plate for the Z-axis. Milling away some of the plastic worked wonders for the clearance on the DRO. The X-axis scale was installed on a couple pieces of aluminum milled to fit in the groove on the face of the table. I then used a small spacers to hold the scale off the table which allowed me to retain the regular endstops. I ended up replacing that little metal piece that the endstops used to hit with the DRO sensor. A single hole drilled and tapped in to the saddle makes for a good anchor point for it. The spacers I made ended up having a secondary use, because after installing the DRO, I decided a chip guard might be a good idea for it. I used a 1 1/2" strip of aluminum I had lying around to make the guard with. It looks pretty clean and does it's job. Eventually, I'll make a panel to hold the DRO gauges.. Probably after I put the fine feed wheel back on the Z-axis.. Apparently I forgot about it. Sleep is going to be a wonderful thing tonight..

[Morndenkainen]

Side note: I'm still waiting on my ball screws to arrive.

[tone1963]

Side note: I'm still waiting on my ball screws to arrive.

I was working on power draw bar

[Morndenkainen]

Attachment 273810

So my ball screws have finally started arriving via the slow boat from china. Apparently I ordered them right before the chinese new year and everything shut down.. Shipping took forever... The Y axis was the first to show, the X is in chicago and should be here in a couple more days. I ended up taking off the table and saddle to remove the parts that the original acme screws thread into. No reason not to use them, everything's already centered and set on them. Ran into another problem though. The OD of the ball nut is 28mm. Realistically there's two way's to handle this. Just drill and tap a couple holes on to the back of the part and call it a day, or do it right and punch out the hole where the threads are and then mount the ball screw properly. I'm going to do it right, so I ended up ordering a 28mm drill bit from hong kong.. Here's to another 2 week long wait... On the upside, I've got enough other stuff to do to keep me busy for a while.