DIY 2 X 72 Belt Grinder With CNC'd Components

[aarggh]

Just spotted this one John, great looking build mate! I really like the degree of flexibility it offers.

From memory I think this must have been the one John Grimsmo referred to in the video of the one he is building?

cheers, Ian

[HelicopterJohn]

Hi Ian,

First thanks for the favorable comment.

I am in the process of designing a truly Multi-Tool Rotary Platen. I have seen designs with a flat platen that tilts a certain amount. I have seen designs that have say a 2" and a 4 inch wheel that can be flipped. Some of these are just locked down with a nut or handle and could??? possibly rotate during operation which could???? be BAD NEWS. My design incorporates multiple tools on one tool bar with easy selection of available tools via an indexing plate and spring loaded tool locating and locking pin.

My design has a fixed plate that attaches to the 1 1/2" square solid aluminum bar and has holes drilled a different positions around a 360 degree arc. My design of the rotary platen tool plate will have a 4" wheel, 2" wheel, with a flat platen backing plate. It also has a small wheel attachment incorporated into the design that can accept various diameters of small contact rollers that are easily replaceable. The rotary platen can also be rotated to different positions for free belt operations and has position stops to accommodate many grinding needs. The platen also has a spring loaded locking pin to make sure that the rotary platen can't rotate once the appropriate roller or rollers are positioned to the front of the grinder. To change to a different position on the 360 degree arc you just loosen the center bolt tension, pull out the spring loaded pin and rotate and lock it to the next desired position on the 360 degree arc, retighten the center bolt nut/handle. I have been working on this idea for a month or so and I hope to cut the parts on my CNC machine by next week. To my knowledge this is the first such Multi-Tool Rotary Platen of this design. I believe it could be easily adaptable to most any DIY 2 X 72 Grinder. Just a matter of having the correct spacing to position the contact wheels so that they line up with the grinder drive wheel and idler pulley.

I have several items ordered for completion of this item and hope to have them all by next week. I will post some pictures as I progress through the machining, assembly and installation on my 2" X 72" grinder.

John

[aarggh]

I'll be watching that keenly John, I'll have a lot more time over the next year to potentially do my own, and building a flexible sander/grinder appeals to me more than buying a bunch of single purpose tools.

cheers, Ian

[HelicopterJohn]

Still waiting on my contact wheels from Sunray. Hopefully they will be here by the middle of the week.

Here are some pictures of my plastic mockup utilized to verify belt length and other fitting requirements.

[HelicopterJohn]

Still waiting on my contact wheels from Sunray. Hopefully they will be here by the middle of the week.

Here are some pictures of my plastic mockup utilized to verify belt length and other fitting requirements. The finished Rotary Platen will be made from 6061T6 Aluminum with all Heli-Coiled threads and drill bushings on main rotating parts. Please excuse all the mockup stuff but at least it will give you an idea of what the finished item will look like. The spring loaded locking pin in the photo will be utilized to lock the Rotary Platen into the indexing plate on the tool bar to position the desired contact wheel in the appropriate grinding position.

I have designed but yet cut the HEX support alignment bar that will key into the sides of the small wheel attachment to keep the outer side frame from rotating. Once complete I will trim the outer side of the small wheel attachment to allow for easier access of belt threading. It is shown in the last photo.

Here is a link to a You Tube Video that gives better detail on my design and how the Rotary Platen Indexing System works.

John

[HelicopterJohn]

Hi,

My contact wheels finally arrived. Here is a little video on the different rotary indexing positions to give you and idea of how it works. Still have work to do but thought I would at least give you a little update. I also got an 8" contact wheel. I am machining the necessary spacers for it and will post some pictures once it is done. I am thinking about utilizing the same tool bar and just removing the platen and replacing that assembly with the 8" wheel. I will see how that works.



John

[HelicopterJohn]

Hi,

Here is a couple of pictures of the new contact wheel with associated vertical and horizontal tool rests. The 8" wheel fits on the same tool bar as the Rotary Indexable Platen. The platen mounts next to the indexing plate on the tool bar and the 8" wheel has a machined spacer to give it the correct offset. Switching from the Rotary Indexable Platen to the 8" wheel is easily done. Just remove the attaching nut, remove the platen and install the offset spacer, wheel and nut.

John

[relax1]

John,
It looks like an intricate mechanism. The engraving plate gives it a nice touch.
I notice most belt sander have harden rollers were the belt goes around for wear purpose. Just wonder how the aluminum would hold up over time? Just an observation!

Hats off to you! You have improved your machinist skills quite considerably since the early days of purchasing the TMP CNC.

I need to swing by a take a look at it ounce is all finalize.

Merry Christmas !

Luis

[HelicopterJohn]

Hi Luis,

Thanks for the favorable comments. It has been a long road, but fun to travel. Ha Ha Actually, most of the 2 X 72 Belt grinders out there have Aluminum drive and tracking wheels. The only issue could be where the grit side of the belt contacts the 2 each polyurethane rollers that keep the belt flat on the small wheel attachment. Others have utilized this system and the wear on those was not a big factor as the wheel is actually turning with the belt. Hopefully, this will work fine. I talked to the guys at Alro Metals this afternoon and they have some .500 thick 6061T6 plate. I will probably stop by there on Thursday and pick up the material.

Looking forward to your visit in the near future. Who knows, maybe I can learn a few new tricks. Ha Ha

Merry Christmas and a Happy and Prosperous New Year

John

[HelicopterJohn]

Hi,

I finally got around to modifying the Small Wheel Attachment. I shortened both sides of the attachment. The shortening of the outside bracket makes for easier belt threading. The rear hole on the inside bracket will be keyed to a .375 stud allowing for a 1 bolt locking mechanism. The inner hex locking mechanism will prevent any rotation.

John

[HelicopterJohn]

Hi,

The Plexiglas material was fine for prototyping to prove the model would work but lacked the rigidity required for actual operation.

Well I finally made a suitable fixture for holding the Rotary Indexing Platen aluminum plate for machining. I made the fixture plate yesterday and Heli-Coiled the 4 mounting bolt holes. I calculated the necessary dimensions for alignment of the holes drilled in the platen plate with the fixture plate holes. It was a bit of a challenge as the Y Axis movement of my machine and the vice location.

I cut the aluminum Rotary Indexing Platen plate this morning and Heli-Coiled all the bolt holes. Installed it on the grinder and it is working really well. The spring loaded locking pin is a great safety related added touch. Trimming the ends on the small wheel attachment makes it easy to thread the sanding belt when that option is utilized. I still need to make a quick release lock handle and the platen backing plate that mount to the Rotary Indexing Platen.

Here a few pictures to show the machining process and the installed Rotary Indexing Platen Plate in different positions.

John

[HelicopterJohn]

Hi,

Finally got around to making some quick release locking knobs for the tooling plate arms and the Rotary Platen Plate. These make adjustments to the tool rest tables very easy and the one for the rotary platen just needs to be slightly loosened and the spring loaded pin pulled out to advance to the next position in the 360 degree arc and then retightened. No wrenches required.

I also made the backup platen plate.

I have attached a few pictures.



John

[HelicopterJohn]

Hi,

I changed the bolt length on some of the knobs to allow easier access. I also made a knob for the small wheel attachment so that it can easily be removed. The rear bolt was replaced with a pin so that all it takes to remove the small wheel attachment is loosening of one knob.

John

[HelicopterJohn]

Hi,

I was experiencing some over heating issues on the contact wheels do to the tightness of the bolts holding on the contact wheels on the Rotary Platen. I reduced the thickness of the inner spacers and installed a hex nut that I could lock against the rotary platen plate and thereby adjust the tension applied to the contact wheel bearings. This worked fine and now the contact wheels are running nice and cool.

Here are a few pictures so you can get an idea of what I did.

John

[HelicopterJohn]

Hi,

I picked up a used Rockwell/Delta machine stand over the weekend that I intend to use for the stand for my 2 X 72 Grinder. I have made a few modifications to the stand to better suit my grinder needs. I wanted it portable with 2 each wheels on the rear of the stand that would allow it to roll around the shop when the front end of the stand is lifted via a retractable handle. When the handle is released the stand sits on the 4 each OEM rubber pads that keep it from movement during grinding operations. The handle is also retractable so that it can be moved inward during grinding operations so that it will not hit you legs. I also attached a side plate for spare attachments, tool rest accessories etc.

I still have to make the top plate that will also have pocket holes for tool bar storage and other accessories.

John

[HelicopterJohn]

Hi,

I installed a piece of gray PVC plastic for my table top. I also installed a lower shelf for storage as necessary. I will probably mill some pockets on the rear side for storing tool bars, tool rests and other accessories. With the front sliding handle and the 2 rear wheels it is easily moved around the shop or even outside on my concrete apron for grinding operations. All of the electrical plugs have twist-lock connectors.

I have included a few pictures of the Rotary Indexing Platen in different positions with associated tool rests.

I am pretty well finished with the basic grinder and portable stand. I may make a few more accessories for the tool rests.

I am now going to design a tool bar with has a contact wheel on one end and a Scotch Brite wheel on the other.

John

[HelicopterJohn]

Hi,

I started work on the Pillow Block Tool Bar yesterday. Machined the pillow block mounting plate and drilled and tapped the 1 1/2" tool bar and attached the pillow block mounting plate with 4 each 3/8 X 16 bolts. A test run with motor power with the belt just riding on the shaft showed good belt tracking. I installed some temporary bolts to check the fit and today I purchased the correct attachment hardware. I still have to decide on the 1" diameter shaft configuration. i.e. length of shaft contact/drive wheel size, attachment method and finishing of one or both ends with threads or other attachment methods for the Scotch Brite, buffing or other finishing tools. I haven't decided on the contact/drive wheel size. I have a 5" drive wheel on the 1725 3 Phase Motor. The VFD has a 2X option which will allow the 1725 3 phase motor to turn 3450 if desired.

John

[HelicopterJohn]

Hi,

Here is an update on my progress of my Pillow Block Tool Bar. Still have a few things to do but the concept is working GREAT!

Here are a few pictures of the Pillow Block Tool Bar. Finally got around to cutting the threads to hold the Scotch Brite wheel on and made a drive pulley. I have installed a Plastic Insert Locknut to prevent the wheel from coming loose. I will use those Plastic Insert Locknuts on both ends of the shaft. I also intend to machine a couple of flats on the shaft so that I can hold the shaft with a Crescent Wrench for changing finishing/polishing wheels.

The aluminum contact wheel is 2.5 inches O.D. and motor drive wheel is 5. inches O.D. If I run the VFD at 50% it should turn the Scotch Brite wheel about 3450 RPM. It now looks and sounds like it should. I still need to cut the other end off and thread it for other finishing wheels.

John

[HelicopterJohn]

Hi,

Well, I finished up the Pillow Block Toolbar this morning.

Well this project is finished except for drilling some mounting holes in the table top for storing the tool bars when not in use.

Now it is time for grinding dust etc.

[turambar4]

Awesome looking grinder man! I was planning on designing my own grinder soon, but starting with your design would be a great time saver. Would you mind sharing your design files, possibly CAD? All credit would go to you.