[davo727]

Hello, I was trying to decide whether to post in the benchmill forum or here when another member who has an IH mill asked me to post my mods in this forum due to the similarity between the Ih mills and the r45 clone and Zay 7045 mills. The mods should apply and benefit any of the brands. I went with a zay7045 from wholesale tools because I was able to pick it up at their store here in houston area. One thing I didnt like were the bolts that went down through the column and threaded into the base. Not good if you are gonna loosen and tighten a million times during tramming fun. I decided to drill the threads out of the base and run 5/8 grade 8 bolts up through the bottom with nuts on top of the column flange. First I reinforced the area the bolts go through by adding a steel plate underneath. It is .750 thick , 1.5 in wide and about 6.5 in long. They are secured to the base by a countersunk 3/8 bolt in the middle and two 1/2 in dia setscrews that are threaded all the way through the base and the .750 strap and then there are jamnuts on the bottom you can see in the pic. The setscrews are ground flush on the top surface where the column sits. The 5/8 bolts each have a tab welded on the head that keeps them from spinning. Dave

[davo727]

The capscrews that are in the column flange are 1/2- 13 thread and allow me to figure out the column tram error in about 5 minutes. I am going to grind the bottom of the column to eliminate the error after I reassemble the table and z-slide. The gearbox doesnt have to be installed. The magnetic base can be attached to the Z slide and the indicator slid up and down on the back and side of a right angle block on the table to figure out the error when moving the vertical up and down.

[davo727]

Hi, Next I filled the base with Epoxy concrete to stengthen it , add weight and dampen vibration and chatter. I posted the details in the engineering forum here on cnczone in a big thread about Polymer concrete construction in machine tools. I made a frame insert from 1/4 thick by 4 inch mild steel welded together. It drops down into the base and I drilled and tapped the base for 4 3/8 bolts to secure it. It keeps the epoxy in the areas that I want it until it cures. You can see I boxed around the bays where my column attach bolts go so no mix goes in those areas. I want to keep access to that area. There is also plumbing installed for the y axis way pressure lubrication. I put in pipe inerts for the mount bolts from the base to the bench to go through. Also a tube for a large bolt to go up through the base and column.

[davo727]

OK starting weight of base 100 lb. Steel frame 15 lb. Completed weight 180 lb. So 65 lb of epoxy, sand, rock mix. There is also a pipe embedded in the Epoxy mix that the 1.25 in dia bolt goes through. The vertical column that bolts here will have the bottom 5 or 6 in filled with Epoxy mix with another pipe insert for the mega bolt. A plate and nut on top of the Epoxy and crank down the nut should give some huge clamping force to hold the base and column together. The big bolt is 4140 B7 steel alloy threaded rod from grainger. The B7 rating is between 100 to 120K psi tensile strength. The rod was about $33.00 for a 3 ft pc. Im gonna have to go buy a 1 3/4 in socket for that darn big nut

[davo727]

For all the details on doing the epoxy fill go to this thread http://www.cnczone.com/forums/showthread.php?t=30155 I think my part starts somewhere around page 47 http://www.cnczone.com/forums/showth...=30155&page=47

[Runner4404spd]

wow! really nice work. what do you plan on doing with it that your reinforcing it so much? i realize that all the extra mass adds alot in terms of vibration damping although i wonder if you need to get more epoxy and rock further up the column to really stiffen it. i guess before i go to all that trouble i will be buying a full up cnc mill from Haas or hurco or someone. but definitely keep up the good work.

[davo727]

Hi, Thanks, Im going to do a full cnc conversion on this. Im figuring out the design for the Z ball nut mount right now. After that I will be able to see how far up I can fill the column without interfering with the ballscrew. I plan on using it for some motorcycle parts and auto stuff. I just figure I am going to improve it wherever I can without spending a fortune. A haas or other vmc is not in my budget so I plan on making my mill as good as I can. I dont see this as work or trouble, I am enjoying working on it. Dave

[BobWarfield]

Very cool work, and nicely done!

Did you have a chance to use the mill much before you tore it down? I'm wondering if you'll have any basis on which to compare the "before and after" improvements?

I am seriously tempted to do the epoxy fill as I work out my own IH CNC conversion. I have two mills and plan to leave the original operational manually as I work on the second. This will give me some opportunity for before and after tests.

It also lets me use the original mill to do machining on the second one as needed.

Best,

BW

[davo727]

Hi Bob, Thanks. I just got the mill in feb and just played around milling a few aluminum pieces before tearing it down so I wont have any real before and after comments. I think as designed the bases have a lot of potential of flexing and twisting and think the epoxy fill will prevent any kind of movement. Filling it wasnt that hard. Simpler methods could be used to section off the base to contain the epoxy than the way I did it. You could use relatively thin aluminum sheeting attached and sealed to the base with 5 min epoxy. Also if your not using studs from the bottom like me then you dont have to section off that area. Then fill with epoxy concrete mix. Its great you have an extra mill, you avoid the chicken and egg problem. I have to put mine back together to make the mounts for the ballscrews and bearings. I assume you have your manual mill trammed good so you can make good parts for your conversion? I made another comment in the cnczone suggestion forum that this IH board should be for all the square column IH, Zay7045, R45 clones, not just IH marketing. Theres no good info for these in the Benchmill forum, just mini x1,x2,x3 stuff. Later, Dave PS--- I have some more mods to the basic mill to show in a few days. Then will get started on some of the cnc stuff.

[Cruiser]

This is fine and good i spose but i had about .015" twist in my base needing pulled out when i fitted it to the frame of my table. will yours still move ?

[davo727]

Yeah I see your point if the base is twisted you wouldnt want to cause it to be locked into a twist. You should be able to shim it and clamp it down square and true upside down on a bench and then fill it and it should stay straight at that point. I know the Y- axis ways on mine are nice and straight and flat with no twist.

[philbur]

I wouldn't bet on it staying straight.

Regards
Phil

You should be able to shim it and clamp it down square and true upside down on a bench and then fill it and it should stay straight at that point.

[Runner4404spd]

thats a good point. you may have to regrind the mating surfaces and ways after the epoxy sets.

[sensph]

I,ll be very interested to know if the epoxy concrete does cause any warping of the frame?

I just happen to have my IH / RF-45 / ( insert 100 other names here) in bits after lapping the axis. Also noted a good 2-3 thou movement both back and forth of the column wrt the base under fairly forceful both arm pressure.Ie enough to tip the front of the mill an inch off the floor. Its attached to a substantial cast iron stand.

2-3 thou measured between table and colum casting. . I know this sort of movement has been reported before and has been said to be typical of mills of this size / cost. But i was thinking of trying to make it a little more rigid somehow.

Epoxy concrete might be an option. After all that effort lapping and no means to grind i dont want the ways to warp though!

like many i have limited budget and space and enjoy the challenge of eeking out a bit more from the machine tool than might be thought possible.

Please keep us informed of any warpage or not and how the machine shapes up when re assembled.

[philbur]

I think the epoxy gives good vibration damping properties but I would be more skeptical about any worthwhile improvement in stiffness.

If anybody has the modulus of elasticity for the material its relatively easy to estimate the magnitude of improvement in stiffness that is possible. (I volunteer).

Filling sections with sand is a simple, easily reversable means of improving vibration damping.

Regards
Phil

PS:
For stiffness there is no substitute for broard/wide sections.
For vibration damping there is no substitute for mass.

I,ll be very interested to know if the epoxy concrete does cause any warping of the frame?

I just happen to have my IH / RF-45 / ( insert 100 other names here) in bits after lapping the axis. Also noted a good 2-3 thou movement both back and forth of the column wrt the base under fairly forceful both arm pressure.Ie enough to tip the front of the mill an inch off the floor. Its attached to a substantial cast iron stand.

2-3 thou measured between table and colum casting. . I know this sort of movement has been reported before and has been said to be typical of mills of this size / cost. But i was thinking of trying to make it a little more rigid somehow.

Epoxy concrete might be an option. After all that effort lapping and no means to grind i dont want the ways to warp though!

like many i have limited budget and space and enjoy the challenge of eeking out a bit more from the machine tool than might be thought possible.

Please keep us informed of any warpage or not and how the machine shapes up when re assembled.

[davo727]

There is some good info scattered through this 74 page thread in the engineering forum here http://www.cnczone.com/forums/showthread.php?t=30155 on epoxy concrete. Various sources have said the epoxy doesnt shrink or expand when it cures so if the part is straight when you fill it why should it be anything but straight after? As far as stiffness goes the mix in my base is 82% rock and sand , 18% epoxy by weight and it is literally a rock now. That epoxy mix doesnt flex. If you hit the side of my base with a hammer now its just like hitting a boulder. It is ridiculously strong and stiff now you could park your car on one corner and it wouldnt move. Some tech info and strength figures on this page: http://www.accurescasting.com/polymer.html They say 10 times better vibration damping than cast iron. 4000psi tensile strenght, 18,000psi compressive strength. There is a modulus of elasticity figure also but im not an engineer so I wouldnt know what to do with it, Im just an airline mechanic Later, Dave

[philbur]

Hi Dave,

Modulus of elasticity is a measure of how much the material will deflect under a given load. Which for machine tools is a much more interesting number than the tensile or compressive strength as, in our case, we are mostly concerned with deflections, not physical failure. So here are some M of E’s for the materials of interest:

Epoxy aggregate 4,500,000. psi
Granite and concrete 5,000,000. psi
Regular cast iron (CI) 14,500.000. psi
Nodular iron (NI) and all steels 29,000,000. psi

The larger the number the less elastic the material is. So as you can see that granite and concrete is actually significantly more elastic than iron or steel, by a factor of between 3 and 6. This seems to go against intuition but is a fact, no argument. This elasticity should not be confused with percentage elogation prior to failure. Which of course is much smaller for granite than steel.

So here are some practical examples of deflection for a square column mill.

Case 1: A 24” square column with a cross-section of 5” x 5” and a wall thickness of 0.5” made of regular cast iron. The beam is fixed at one end and a force of 150lb is applied to the other end, at right angles to the beam axis.

Case 2: as in case 1 but filled with epoxy

Case 3: as in case 1 but using nodular iron or steel

Case 4: as in case 3 but filled with epoxy

Calculated Defections
Case:
1. CI without epoxy - 0.00155”
2. CI with epoxy - 0.00128”
3. NI or steel without epoxy - 0.00078”
4. NI or steel with epoxy - 0.00007”

It is also interesting to note that all steels effectively have the same modulus of elasticity so, if you are trying to add stiffness to a structure, regular steel is equally effective as any kind of super alloy steel.

Regards
Phil

There is some good info scattered through this 74 page thread in the engineering forum here http://www.cnczone.com/forums/showthread.php?t=30155 As far as stiffness goes the mix in my base is 82% rock and sand , 18% epoxy by weight and it is literally a rock now. That epoxy mix doesnt flex. If you hit the side of my base with a hammer now its just like hitting a boulder. It is ridiculously strong and stiff now you could park your car on one corner and it wouldnt move. Some tech info and strength figures on this page: http://www.accurescasting.com/polymer.html They say 10 times better vibration damping than cast iron. 4000psi tensile strenght, 18,000psi compressive strength. There is a modulus of elasticity figure also but im not an engineer so I wouldnt know what to do with it, Im just an airline mechanic Later, Dave

[agar13]

Has anyone tried to increase the spindle speed on this or anyother machine besides the IH.

[davo727]

Agar: We may be able to simply swap the motor for a 3470rpm unit. Saw thats what Cruisers IH mill came with in a 2hp. 3470 rpm would give around 4000 rpm instead of the 1970 or 2000rpm with the stock motor. You can get a 3 phase motor and then use a VFD with single phase 220volt power to adjust the speed. I know some members have done it. Maybe they will offer some advice or you can do a search here and find something. There may be a durability issue with the higher speed motor but I think I am going to risk it and see what happens. If it breaks I will fix it. Dave

[Runner4404spd]

see my thread about changing motors. i built an adapter to mount a 56c motor to the D80 drive on the IH. the 3450 RPM motor works great.