[pete from TN]

I just found their site and they look pretty good and the price does not seem to be all that high. I want to use some 3/4 inch screws on my Lathemaster but I cannot tell which dimension is the od of the screw itself. Anyone got any ideas? Peace guys...

Pete Matos
[email protected]
865-363-9218

[cadmonkey]

Well the one's they're using now are 16mm ball circle - basically the same as a 5/8" screw with a 5mm lead - similar to .2". I almost used them but the size of the nut was too big for the X3 according to my solid model and I didn't want to go grinding on the nut body especially since they're internal return types. If they'll fit your application go for it and let us know. I haven't read much about the new screws except for the one email I exchanged with them that the root diameter is actually 12.9mm (a hair over 1/2") - surprised they haven't fixed that misprint yet...

I ended up going with Nook Precision Rolled XPR screws, with the lower grade cut nut @ $30 each (the ground nuts are about 10x as much) double nut on the X and preloaded the balls on Y - I'm going to get their adjustable preload nut and flange for the Z when I finalize that design - price for that is about the same as the homeshop nuts for the current screws. I did my own screw machining (it's not as hard as many think if you have the equipment and ingenuity to make what ya got work).

[acondit]

I ended up going with Nook Precision Rolled XPR screws, with the lower grade cut nut @ $30 each (the ground nuts are about 10x as much) double nut on the X and preloaded the balls on Y - I'm going to get their adjustable preload nut and flange for the Z when I finalize that design - price for that is about the same as the homeshop nuts for the current screws. I did my own screw machining (it's not as hard as many think if you have the equipment and ingenuity to make what ya got work).

Cadmonkey,

Where did you find the Nook XPR screws?

Alan

[cadmonkey]

www.nookindustries.com you can request a catalog and they'll send it free (and quick) and then you can do a request for quote over their website. The website has an interactive catalog (no prices) and you can download 2D & 3D cad models in a variety of formats - I verified my design fits before spending a penny and didn't have to draw any of the possible solutions. Very handy. I forget what I paid per foot for the screw, but it was very competitive with others and then cut the 6' stock length with a cutoff wheel on my angle grinder. The woman I traded emails with getting the right parts (as I was SHOCKED at the cost of the nuts I originally designed around) was very helpful and responded to questions quickly and in depth.

Still - I'd like to see some people who've gone out on a limb and gotten the new homeshop screws - I have future projects which their offerings might be well suited for. Not trying to bash them by any means. They used to carry the Nooks so that's what I started designing around then they stopped the Nooks and went to their own screws.

HTH

[sergizmo]

I am designing a small mill around the homeshopscnc screws. They offer machining services which was a big factor in picking them. I can't machine the screws at home. Another was the internally ground nuts preloaded to zero/almost zero backlash. No need for two nuts on each screw.

The calculated cost for three screws with nuts, three fixed end support, one free end support, and all machining was just under $1,100. Ready to go, no work required. Not bad at all for a set of what appear to be quality drop in screws with supports. I figure this is about as good as it gets quality wise for a rolled screw setup, and a ground one ready to go would be in the $2,500 plus range.

I just wish they carried some smaller linear guides.

Serge

[pete from TN]

Of course I will not be needing the end supports and I will be machining my own screw stock. I think I wanna go with some 3/4" screws with sero backlash nuts rolled screw stock for all three axes. Just dunno is $400.00 will cover all that. I think they said the Homecnc screws was like $1.98 per inch and the nuts were like a hundred each. Lesse here, x is prolly around 34, y is like 16 and z is like 36 which comes to around $170.00 plus shipping plus three nuts at $300.00 oh well so much for my $400.00 huh. And those are not even 5/8 inch screws you say. I think I will check out the nook catalog you mentioned, anyone else have some input on this? Thanks all....peace...


Pete Matos
865-363-9218
[email protected]

[lgalla]

Reid Supply has Nook and Thomson with good online pricing
Larry

[cadmonkey]

You can definitely stay under the 1k mark. My order for 6' of screw (enough for my x,y and z) three nuts (enough for x and y) was right around $300. Add the Z preloaded nut and a mounting plate for it and my screw related total will be right around $500. Toss in some wipers since I didn't get them the first trip around and maybe I hit $600. Add the Al stock and misc bearings and hardware and my mechanical portion of the conversion is under $700 even if I get the wipers.

Self machined the ends though - it would've been hell to make Homeshop's end blocks work around my table's dimensions...

And Serge - we of course expect pictures when you get the machine built

That reminds me I need to start prepping my pics...too many tasks, not enough hours...

[sergizmo]

Yeah guys that cost is for everything. Drop in units. X is supported on both ends and Y and Z on one. Here is the breakdown.

Stock: $1.89 X 48" = $91
Ballnuts: $95 X 3 = $285
Fixed end support: $120 X 3 = $360
Free end support: $55 X 1 = $55
Machining fixed: $85 X 3 = $255
Machining free: $25 X 1 = $25

Total: $1,071 plus shipping and whatever crossing the border costs.

Seeing as my lathe is a Sherline there is no way they are getting machined at home. Paying a job shop would be just as expensive (I don't have any hook ups) and there is a risk it may not be a good fit for the supports. Having homeshopcnc machine them assures that they will fit the blocks properly.

cadmonkey: It will be a little while before I start building. Still CAD drawing the machine (on second design), and I need to launch the business and start selling putters to get the cash needed. Once the cash is in hand building this mill will be priority #1, my Sherlines won't last long.

The base is a 18 by 12 by 3 granite surface plate drilled for steel inserts. The base components will be screwed into tapped holes in the inserts (Risers for rails, end plate, column, etc...) and an angle plate will be used to help support the column. Structural parts will be aluminum. Will be using aluminum putty to get parts really flat and reduce machining time. An X2 R8 spindle box with the belt drive conversion and Tormach tooling system will be used. Thinking about a DC motor with one of those dimmer switch type speed controls in the 3/4HP range. Looking at a Keling ready built contol box (The more powerful one) and steppers from them as well. Also will go with flood coolant and an enclosure. Might use with limit switches, but not for a while. Mach 3 will be the control. Hope to be in the $5,000 total range including absolutely everything (including Tormach tooling).

When it's well under way there will be a thread in the building log forum.

Serge

[cadmonkey]

I think I've seen you mention that setup before (or someone with something similar) - I recall the cringing of people thinking about drilling their precious granite plates Good luck! I'm itching to finish mine but looks like this weekend will be doing work for/with the landlord renovating the kitchen ceiling and soffit walls. Since he isn't as adept at drywall I've got my work cut out for me on that...especially since it's a 2 piece suspended drywall system...in section an inverted U with an inverted fat T supported on threaded rod with lighting on top and bottom of the T... It'll look fantastic when completed but it's gonna be a female dog...

[RotarySMP]

Precious granite plate? Mine is an 18x12x3 grade A (at least that is what the "quality certificate" says) and it cost me something like $19 from Shars.

I have been thinking of making a whole mill frame out of these cheap chinese surface plates.

[Bird_E]

Pete,
I woud go with 3/4" screws. The 5/8 are perfect for the X3 and smaller machines. but the RF45 needs a little more.
Also, Check www.mcmaster.com
The have screws and nuts as well.
bob

[cadmonkey]

Precious granite plate?

Well I remember the poster responding basically like that to someone who posted about their precious Starrett plate. Yeah, looking at a Shars for benchtop use myself but the hsipping is killer. My local tooling supplier has their catalog behind the shelf, maybe I can get one a bit cheaper through them. Their own catalog only has Starrett plates, no economy plates.

Good luck!

[pete from TN]

My new friend Bill south has a lathemaster already done and he has 5/8 screws on the x and y and a 3/4 on the z and he said the z was the only one that really needed the extra beef because of the weight. He said the 5/8 on the x and y was enough to snap a 1/2 inch endmill don't ask him how he knows.... I would like to go the way you did with the 3/4 ground but short of finding a super deal on fleabay it is prolly not gonna happen. I'm thinking 3/4 rolled all around with some nice preloaded ballnuts would be about the best my thin pennies could buy right now and from what I am reading that should be more than sufficient for this chinese iron. whaddya think? Peace... By the way, shoot me an e-mail at [email protected] if you wanna chat more about this stuff. I am not that good at typing and I find you get more done over the phone. Altho I understand if you like your privacy for sure. Peace man...

Pete Matos
[email protected]
865-363-9218

[pete from TN]

I have been thinking about the cost and machining of the ballscrews. Do you guys think there is any reason you could no machine a nice piece of drill rod to fit the angular contact bearings and thread for the locknut and the pulleys and then bore it on the end to accept the ballscrew. In my mind this would do two things, it would make perfect alignment easier because you would be able to machine the drill rod bore to fit very nicely over the od of the ballscrew and you would also not be paying for the extra ballscrew length that you will be basically machining off. I have a quality Tig welder and I am sure I could probably put a nice bead on it and maybe even plug weld it inside the bore a little. Do you or anyone you know use this setup, is there anthing wrong with this idea? It would also nullify the necessity of grinding thru the hard outer surface of the ballscrew? What say ye? This is not gonna be cheap and I am trying to find ways to save money to hopefully purchase better screw stock and motors and all the rest of the cnc symphony. Thanks in advance guys...peace...


Pete Matos
[email protected]
865-363-9218

[cadmonkey]

In theory it could work. I think you're going to have a hard time getting the screw concentric with the fitting unless it's a ground screw, the rolled screws have some variation in the diameter of the lands, even though we're only talking 10 thousandths on my screws. As for the distance you're machining off - on a rolled screw it's probably only around $20 worth (figuring $2/in). The case hardening is really overblown. My pneumatic die grinder and a cheap hardware store grinding wheel took it off in short order. Bigger compressor and I could've taken heavier cuts and been done sooner. Once you're through it's butter. Did it on a 7x10 HF lathe with brazed carbide bits.

We'll never know for sure if it works though until someone tries it...only caveat - if it doesn't work - you wasted the whole length of screw - less the length you can use on the Y axis (ie try the X first...).

[acondit]

I have been thinking about the cost and machining of the ballscrews. Do you guys think there is any reason you could not machine a nice piece of drill rod to fit the angular contact bearings and thread for the locknut and the pulleys and then bore it on the end to accept the ballscrew.

Pete Matos
[email protected]
865-363-9218

Pete,

That is basically what I did on my lathe conversion, only I used 12L14?? leaded steel. Look in this thread messages 15-22.

Alan

[cadmonkey]

Well that does give more validity to the theory! Thanks for posting that Alan - I need to read the rest of that thread, looked very interesting.

Pete - with Alan's results I'd say give er a go.

[pete from TN]

Thanks for your input on the machine add on end to mate with the ballscrew. I see how alan made a press fit and using heat/cold insterted it in the lathe. I am sure I could accomplish the same thing in my 12x36lathe. I figure the question comes to how straight were you able to get it and did the press fit hold under extreme torque applied during heavy machining. You did it basically a little different than I am thinking I will. I was going to make a bore that will accept the entire diameter of the ballscrew instead of the turned down press fit portion you made. Then a little buzz with the tig and I was hoping I would be able to make it fit nice and straight. It seems to me that a fitting turned between centers and then carefully bored to be a slight friction fit of the end of the ballscrew and then a tig weld should in theory ensure a strong joint and a concentric alignment no? I may be grasping at straws here but if your press fit worked then a tig welded joint should be just fine too... The major reason I am considering this is to be able to ensure the concentricity so I don't have to worry about misalignment with the ballnut mounts. Am I worrying about nothing here or is this a critical issue? I lean on the experience of those on the board who have " been there and done that". Thanks guys, I really like the looks of your grizzly cnc lathe. Maybe once I get my bearings with this mill conversion and start making some decent parts I will probably want to tackle the 12" lathe next. Peace guys....


Pete Matos
[email protected]
865-363-9218

[acondit]

Thanks for your input on the machine add on end to mate with the ballscrew. I see how alan made a press fit and using heat/cold insterted it in the lathe. I am sure I could accomplish the same thing in my 12x36lathe. I figure the question comes to how straight were you able to get it and did the press fit hold under extreme torque applied during heavy machining.

I don't do very heavy cuts on my 9x20 so I have had no problems with the torque. I can run the z-axis at 60ipm with no indication of runout on the ballscrew.

You did it basically a little different than I am thinking I will. I was going to make a bore that will accept the entire diameter of the ballscrew instead of the turned down press fit portion you made.

Roland Friedstad used that method (fitting a new end piece over the outer diameter) in an article he wrote for Home Shop Machinist about converting a Grizzly G1006 Mill/Drill. He used a snug fit with two set screws in the end-piece, spaced so that they would both go into the thread lands.

Then a little buzz with the tig and I was hoping I would be able to make it fit nice and straight. It seems to me that a fitting turned between centers and then carefully bored to be a slight friction fit of the end of the ballscrew and then a tig weld should in theory ensure a strong joint and a concentric alignment no? I may be grasping at straws here but if your press fit worked then a tig welded joint should be just fine too...

My concern would be the possibility of the weld actually warping the screw or end.

The major reason I am considering this is to be able to ensure the concentricity so I don't have to worry about misalignment with the ballnut mounts. Am I worrying about nothing here or is this a critical issue? I lean on the experience of those on the board who have " been there and done that". Thanks guys, I really like the looks of your grizzly cnc lathe. Maybe once I get my bearings with this mill conversion and start making some decent parts I will probably want to tackle the 12" lathe next. Peace guys....

Pete Matos
[email protected]
865-363-9218

Home Shop Machinist is currently running an article by Roland Friedstad about fitting ballscrew to a Grizzly 12x36.