Simko's Weld Together OSG

Show us your grinder!
Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Simko's Weld Together OSG

Post by Simko » Thu Feb 01, 2018 7:03 pm

A friend and I have been getting into knife making and decided that we wanted 2x72 grinders. After doing some searching and finding prices around $2000, we decided to try and build our own. We were originally going to reverse engineer a Beaumont from pictures, but after doing some searching I stumbled on this website.

I love the design, but I wasn't excited about all of the drilling and tapping... then I saw the weld together version that Kevin Powers posted. I was hoping to get a copy of his weld together prints, but it doesn't look like he is active on here any more.

I decided to start with the Steve Rice Rev2 prints and convert them for welding:

- All of the tabs are shortened by 1/8" to give some surface area to weld
- Front and rear hinge plates were redesigned similar to how Kevin did it, but with more areas to weld
- Converted tracking arm for gas shock. i stretched the pivot point 4" back and 1" up like Kevin did, but that is the end of the similarity.
- Converted the top spacers to be one bolt spacing longer and added shock mount holes to one of the spacers.
- Stretched the top of the arm and added a row of shock mount holes
- The shock is a standard McMasterCarr part and the spacing was selected to have 3/4" of compression and about 1-1/4" of extension when the shock is vertical.
- I spec'ed quick disconnect ball sockets for the shock so that it can be quickly moved from one ball stud to the next. Mount it vertical furthest away from the pivot for full pressure or at an angle close to the pivot for less.

I am hoping to cut these out on my plasma table soon. It's not going to be as pretty as all these laser or water jet builds, but the price is right 8-)

IMG_0988.JPG
IMG_0988.JPG (57.43 KiB) Viewed 1974 times
IMG_0987.JPG
IMG_0987.JPG (52.81 KiB) Viewed 1974 times
IMG_3798.JPG
IMG_3798.JPG (394.71 KiB) Viewed 1974 times

Brian Stucker
Posts: 5
Joined: Wed Jul 12, 2017 6:01 pm

Re: Simko's Weld Together OSG

Post by Brian Stucker » Sat Feb 10, 2018 4:54 pm

How did it work out for you?

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Mon Feb 12, 2018 6:30 am

I cut out three sets of plates over the weekend. Even with taking the time to figure out how much to oversize the slots to make up for the taper of the plasma cut, I still had to do some hand filing in the slots and in the tab inside corners to get everything to fit nicely.

Getting ready to drill all of the holes. I was originally going to plasma peck the hole locations and drill them out on a drill press, but my father-in-law showed interest in a grinder (the reason that we are making three now instead of two) and he has a tool and die shop and is going to do them on a CNC mill. 8-)
Last edited by Simko on Thu Feb 22, 2018 7:10 pm, edited 1 time in total.

srice
Posts: 22
Joined: Tue Aug 22, 2017 6:23 pm

Re: Simko's Weld Together OSG

Post by srice » Wed Feb 21, 2018 7:02 am

Life continues to get in the way of my build and I still haven't cut my parts out. I have been considering converting to a tab and slot weld together design as well. I like the idea better than a bunch of threaded fasteners and with the tab and slot design, the amount of heat/weld needed to hold everything together can be minimized. I am thinking about making the arm spacers as a single flat pieces instead of multiple pieces on edge. Is there a reason you kept the multiple piece spacer design?

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Thu Feb 22, 2018 7:07 pm

srice wrote:
Wed Feb 21, 2018 7:02 am
I am thinking about making the arm spacers as a single flat pieces instead of multiple pieces on edge. Is there a reason you kept the multiple piece spacer design?
I actually changed to solid aluminum spacers instead of the stacked pieces, but I haven't uploaded the files here, because it didn't seem like anyone was interested. I have a build thread going on on PlasmaSpider

http://plasmaspider.com/viewtopic.php?f=6&t=25026

My father-in-law just finished machining the aluminum spacers today... 8-)
IMG_0996.JPG
IMG_0996.JPG (803.17 KiB) Viewed 1726 times

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Wed May 16, 2018 7:25 am

Finally made some progress on this project. It has been a long time coming, but projects priorities change when they’re not at the top of the honey-do list. :lol:
15FD463C-45C5-4A1B-80B8-4BEF7327BACD.jpeg
15FD463C-45C5-4A1B-80B8-4BEF7327BACD.jpeg (810.18 KiB) Viewed 1151 times
E427D906-682C-4D2F-8524-552D2887AB51.jpeg
E427D906-682C-4D2F-8524-552D2887AB51.jpeg (666.73 KiB) Viewed 1151 times

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Wed May 16, 2018 1:33 pm

Deleted REV2 CAD files that were here... See updated REV3 CAD files on Page 2 of this thread... 8-)
Last edited by Simko on Mon Jul 09, 2018 11:41 am, edited 3 times in total.

User avatar
admin
Site Admin
Posts: 124
Joined: Wed Jul 05, 2017 8:03 am

Re: Simko's Weld Together OSG

Post by admin » Wed May 16, 2018 2:53 pm

Wow, you've been a busy man!

Love it.

Any issues that you encountered?

Dan

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Wed May 16, 2018 7:25 pm

admin wrote:
Wed May 16, 2018 2:53 pm
Wow, you've been a busy man!

Love it.

Any issues that you encountered?

Dan
Issues so far...

1) Plasma cutting tab/slot construction sucks even when you try to take into account for the edge taper. Each grinder had quite a bit of hand filing to get all of the tabs/slots to fit. Water jet or laser would of been nicer, but seeing as how I have a CNC plasma table...

2) The bolt heads for the frame spacers in the bottom corners of the left and right frame plates interfere with the front and rear support preventing the grinder from going completely vertical.

3) The curved slot on the front hinge mount needs extended to allow the grinder to go completely vertical it’s short by about 3/32.

4) The front and rear supports needed to be stretched up for the 3HP motor. I had originally also stretched up the gussets, but I found a collision in the model between the gusset and the motor wiring box.

5) I believe I had to increase the clearance hole for the motor and stretch the bottom of the frame plates down about 3/4” so that there was still some meat there.

6). The 3D model provided by WEG for their 3HP motor does not show a small extension at the shaft end of the foot mount. 1/2” needed to be cut off of the foot mount to not hit the frame plate when the motor was installed.

7). I believe I made the aluminum bars longer than recommended based on what it looked like in the model. I haven’t put a belt on it yet to see for sure.

That’s about it so far.

Simko
Posts: 14
Joined: Wed Jan 17, 2018 2:03 pm

Re: Simko's Weld Together OSG

Post by Simko » Mon Jun 18, 2018 7:19 am

I wanted to pass this on to the group as a better way to mount and shim the platen and tracking wheels.

My friend and I got our three 2x72 grinders all put together, but he was the first to get his running. Once he got it running, we quickly found some shortcomings in how the wheels mount to the 'Platen D Plate' and the 'Tracking Hinge Bottom'. We were very cautious of pre-load during assembly but still had issues with all three bearings heating up hotter than we would have liked after only a few minutes of run-time. After a few back and forth engineering sessions, we settled on a new approach.

Current Sayber Instructions

Platen D Plate
- The 1/2" through holes in this plate along with how the bolt was secured with jam nuts allowed for considerable movement in how perpendicular the bolts were to the plate. In theory, this design should work OK, but in practice, the non-machined surface of the nut and the 1/2" hole did not play well together. We could slightly change the angle of the bolt, by loosening and re-tightening at a different point in the rotation.
- The inner bearing rides on the threads of the bolt

Tracking Hinge Bottom
- The threaded hole in this part was slightly better at locating the bolt perpendicular to the plate, but the threads still allowed for some movement. Thread a bolt into a tapped hole and wiggle the bolt side to side to see what kind of play threads allow.
- This design relies on 'precise' tightening of the bolt to eliminate wheel movement but also not put the bearings under preload. (Nearly impossible to accomplish)
- The inner bearing rides on the threads of the bolt

Our Modifications to Platen and Tracking Wheel Axles

Platen D Plate
- Instead of drilling through holes for the 1/2" bolts, we drilled/tapped 3/8-16 holes for a 1/2" shoulder bolt (2-1/2" long). Using a shoulder bolt tightened against the plate locates the bolt perpendicular to the plate and eliminates all movement in this wheel axle.
- Now that you have a stable axle that is perpendicular to the plate, you only need to shim the wheel to the proper distance away from the plate to line up with the other wheels. This is accomplished by using 1/2" ID 'spring steel shoulder shortening shim washers'.

https://www.mcmaster.com/#shortening-sh ... s/=1dc5mmz

These shims can be used between the plate and the wheel and also between the wheel and the bolt head to take up any additional space left on the shoulder bolt. The shim washers can be purchased in a variety of sizes, we bought an assortment of 0.062", 0.032", 0.015", and 0.005".
- Attaching the wheel in this manner allows for the wheel to have no play, is located perpendicular to the plate against the shoulder, and allows the bearings to run with no pre-load preventing early bearing failure.
- Both bearings are now riding on a precise smooth surface instead of on threads.
- Another benefit is that now there is no interference between the nut that held on the bottom wheel and the work rest adjustment rod.

Tracking Hinge Bottom
- Instead of drilling and tapping the hinge bottom for 1/2"-13, drill/tap this location for 3/8-16 and use a 2-1/2" shoulder bolt as described above

The top drawing is how it is recommend to install in the Sayber instructions. The bottom drawing shows how we did it with a shoulder bolt and shoulder shortening shim washers on each side of the wheel.

I hope this helps some people with their build and in my opinion should be added to the official Sayber download as it is a superior way to mount the wheels and is not any harder to accomplish for the DIY'er besides for having to buy some shim washers and shoulder bolts.
shoulder_bolt_mount.jpg
shoulder_bolt_mount.jpg (101.38 KiB) Viewed 783 times

Post Reply

Who is online

Users browsing this forum: No registered users and 1 guest