Author Topic: Mini mill Stand SX2 Plus  (Read 3867 times)

Offline Buell

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Mini mill Stand SX2 Plus
« on: October 18, 2018, 04:45:38 PM »
Heres a few Pics of a Mill stand I have been Making.. Made out Of 100x100 fence post I found at the side of the road ! and some 1/2 " plate I got for cheap as the base. Side cheeks are 10mm i think so pretty beefy.

So my idea was to give some more mass and to try and stop some of the flex in the Head to the base. Also so i could tram the head to the base i put a couple of bolts in the top of the column ...One tapped in and one to push the column away. My thought was to aide in adjustment...works a treat. My only concern is if there is any twist in dovetails on the head.

Its a lot better having tried it today ..just wondering if i should fill it with some dense material.
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Offline Brass_Machine

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Re: Mini mill Stand SX2 Plus
« Reply #1 on: October 18, 2018, 10:32:43 PM »
Looks good. There is a huge thread over at cnczone about using an epoxy/granite mix as fill...

Eric
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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #2 on: October 20, 2018, 08:18:12 AM »
Only concern is if I want to drill and tap any holes in the future ! Masonry bits at the ready!!
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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #3 on: October 22, 2018, 09:14:00 AM »
Ok so the post man just came Looks like the lead screw i ordered of Flea turned up ....wouldn't mind but it came all the way from the East to have a Man from the west in a Red uniform jam it thru the PostBox ...Lets hope its not bent out of shape !

Anyway my idea was Firstly to make a stronger and longer lead screw with larger diameter hand wheel and a way of fixing on the left end of the bed to a stepper motor to enable powerfeed. I can see this just going down the Cnc route but Not at the moment.

Concerns at the moment are...

1. New Lead-screw is stainless machining it !
2. End float Backlash etc. At the mo the old lead has a Nasty beginning to it which is not great ! See photos
3. My abilities to do this !! Rome wasn't built in a day...Well I wasn't on that Job anyway !


Thoughts before I turn something on are...

Machining well that will have to be slowly done and hopefully somewhat carefully. I have a very small lathe with carbide.
End float etc..well Im going to put a Dro set of scales when they turn up from East..Hopefully a different man from the west will NOT put them in my Post box ! so no really worry about the backlash, however when i crank with a drill attached to the lead at the mo on change of direction theres a massive amount of slack in the lead-screw to the drill. My guess is that is not so apparent when you have the dial and crank handle on. But begs the question of do I need to worry about this ? If i did have to then bearings at both end of the shaft would deal with that  angular contact type ..with a mounting point on the left holding the leadscrew before the stepper thus supporting the screw and keeping it perfectly balanced and centred and no end float ...But god that seems very complicated. Please guys say thats Crazy your not building an Aircraft engine !

My abilities Umm they are in Question but You can only do your best with what you were given..I don't mind failing whilst learning. If it were easy everyone would be doing it right.

Any advice help tips Patreon, donations, Youtube, endorsements, Brand Promotion, adds,Banners, etc etc welcome !

All else fails just 3d Print it !!
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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #4 on: October 22, 2018, 09:27:21 AM »
System doesn't allow too many pics in 1 Go sorry
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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #5 on: October 22, 2018, 10:43:45 AM »
...
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Offline WeldingRod

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Re: Mini mill Stand SX2 Plus
« Reply #6 on: October 22, 2018, 07:48:15 PM »
Um... I'll try to hit the high points!
First, take a file or a directory grinder and grind a higbee on the end of the threads.  Then clean the corners of the higbee.  It's used on firehouses and oilfield iron; you need to google a picture because my explanation isnt going to cut it...
Your lead screw needs to have one end fixed axially to one end of the table.  This can be done with a pair of bearings.  You want to run that end close to the nut, then tighten the screws to the table to produce alignment.  The other end can float axially, but your motor's centerline needs to agree pretty well with the nut.  You can do.the same trick (get close to the nut n tighten) on that end.
Btw, I hate what spell check does to axially and higbee!!

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Offline velocette

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Re: Mini mill Stand SX2 Plus
« Reply #7 on: October 22, 2018, 10:21:52 PM »
Hi
Is the lead screw stainless steel as this is unlikely unless that is what was ordered.  Even so It is possible to drill the end and fit an extension shaft to it. The Lead screw nuts of far eastern origin have lots of play that produces lots of backlash unfortunately. The Thrust bearings at the right hand end can be adjusted to give no back lash. A power feed motor That can be mounted to slide  on a couple of rods to disengage the drive using a simple dog clutch for hand feeding is an advantage. 

Eric

Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #8 on: October 23, 2018, 02:43:21 PM »
It is a stainless Acme Trapezoidal lead screw. It does fit the original nut...which is nice !!theres one job I dont have to do at the moment..wont speak to soon.  My idea was to just copy the original block that the crank is mounted to. But then when i saw the state of the end of the original lead-screw I was wondering if either the new lead-screw would wear too quick or the old original nut would wear out quicker. Obviously if its stainless steel and the nut is Cast iron there maybe an issue there? Using the brass new nut ...well the jury is out on that but if i must heh. Bearing in mind that the cranking speed and amount of travel will be increased once it works nicely... i don't really want to take the whole thing apart again to sort another piece of the jigsaw. Do it right once and hopefully it will be good to go. Thats the theory.

At the moment the face of the lead-screw bares against the cast-iron block and thats it, my thought was a bearing to be fitted on the shaft and then i guessed you would have to have a flat thrust bearing on the outside to keep the load on it closest to the crank handle but heh I'm thinking on the fly here.

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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #9 on: October 23, 2018, 02:59:50 PM »
That stainless is no fun to work with.. Old shaft was just under 8mm new shaft 9.2mm by the time i got around to stopping myself. Hole in the block is 12.75mm.
I used carbide index tool was that the right idea, seemed to cut ok but was using it on a mini lathe with power feed something i dont normally do but thought the finish would be better that way ! its just a bit coarse to me . still its all about the learning on the way.
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Offline chipenter

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Re: Mini mill Stand SX2 Plus
« Reply #10 on: October 23, 2018, 03:19:53 PM »
I fitted 2 flange ball races back to back to each of my X1 lead screws , they worked well and reduced the backlash a lot .
Jeff

Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #11 on: October 23, 2018, 05:05:43 PM »
Yes i think a Thrust washer bearing 3 piece will be the option closest to the Hand-wheel.  At the other end the lead-screw will be unsupported as it is at the moment.. but will be coupled to the stepper motor some how.

Now the inner side of the Bearing block where the hand wheel goes Im steering toward an ordinary deep grooved ball race..I have seen some that are either 9mm perfect but 25mm diameter ..which means I have to make a New bearing block as its not big enough to take it !
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Offline velocette

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Re: Mini mill Stand SX2 Plus
« Reply #12 on: October 23, 2018, 09:23:28 PM »
Hi
SKF list a 9 X 17 X 5 mm bearing It may just fit. Cast Iron or Aluminium are easy enough to fabricate housing to fit.

Eric

Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #13 on: October 24, 2018, 02:46:56 AM »
All change ! what about this then...I went to bed last night heard some sounds coming from the other room....thought it must be the wind....woke up this morning ..Look what i found  !

Not sure yet but mocked it up and thought i would see if it works 2x bearings same at either end and new shaft diameter to suit new lead screw dimension. Then maybe i make the real thing after I iron out the things I got wrong ! Quick model in Fusion and hehe.
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Offline Buell

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Re: Mini mill Stand SX2 Plus
« Reply #14 on: October 24, 2018, 02:48:54 AM »
Thanks for the reply didn't see that Skf bearing...
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