Caster Base for Cutter Grinder

[Don52]

To move the cutter grinder from the driveway to the shop I built a temporary caster base made of 2x8’s. The cutter grinder with the temporary caster base is shown below:

1. Cutter grinder on temporary base


One thing strange about this cutter grinder is that the bolt down feet of the cutter grinder and the bottom of the base are smaller than the top. You can see how the top overhangs the base in the following picture.

2. Corner of cutter grinder


The problem with the temporary base is that it sets the top of the table of the cutter grinder 54” above the floor, which is way too high. The cutter grinder is typically used with tooling, which makes this problem worse. The following picture shows typical tooling on the cutter grinder.

3. Tooling on cutter grinder


To solve the problem, I designed a fabricated tubing base to reduce the height of the top of the cutter grinder by 7-1/2”. I selected 2” x 3” tubing with a ¼” wall for the frame of the cutter grinder, because it would fit between the base of the cutter grinder and the overhang on the sides. I did a finite element analysis of the frame and I found that I needed to add the diagonal braces, which are shown below, to get the factor of safety above 2. The following two pictures show the fabricated caster base for the cutter grinder.

4. SolidWorks Asm


5. Closeup of caster

[Don52]

My friend Rick pulled some casters from the scrap bin and gave them to me. I cleaned up the casters and painted them.

6. Scrapped caster


7. Caster cleaned up and painted


The first step was to cut out and machine all of the parts for the caster base. Below shows a picture of chamfering the plate that supports the leveling feet. I have found that with this multi-tooth cutter I can easily chamfer a part with only one pass.

8. Chamfering plate


The next part to make is the block for the leveling foot. I chose to drill and tap in on my Bridgeport. I chamfered one side for a groove weld and chamfered the other side to avoid the sharp block hitting the operator’s ankle.

9. Center drilling leveling foot


10. Chamfering leveling foot

[Don52]

I used my horizontal swivel mast saw to cut out the ½’ plates that the cutter grinder will eventually rest on.

11. Cutting plate


I used some scrap metal for the braces for the leveling foot blocks, which required me to weld up and grind the holes, so that it would look good when I was finished.

12. Welding up holes in scrap plate


13. Welds ground flush


I purchased one 20’ bar of ¼’ x 2” x 3” tubing for this project. I don’t know how prices for steel are in your area but I paid $165 for the tube including the cost to cut it in half for me.

14. Tubing stock


I chose to use groove butt welds for the tubing to get CJP (Complete Joint Penetration). I used my Fireball square to set up the tubing for chamfering.

15. Chamfering tubing

[Don52]

Using a multi-toothed high speed steel cutter again only took one pass per chamfer.

16. Closeup of chamfering


17. Tube chamfered


Here are all of the pieces cut up, chamfered and sanded near the weld.

18. Parts all cut up


The next step was to weld up some scrap pieces to try out my weld parameters.

19. Practice welds on scrap


For open root groove butt weld on a 45° angle on the side of the tube I used the following parameters. This was the default setting on my welder for 10 gage metal.

Process: Short circuit MIG (GMAW)
Welder: Lincoln SP-250
Gas: 75% Ar 25% CO2
Wire: .035” Lincoln L-56 (ER70S-6)
Groove angle: 60°
Root opening: ~3/32”
Root face: ~1/16”
WFS: 237 IPM
Voltage: 18.0 volts
Shielding Gas: 25 CFH
CTWD: 3/8” – ½”

For the fillet weld I used the following parameters. I didn’t bother to groove this joint. I used a hotter setting because I really wanted the weld to burn in for good penetration. This is the default setting for ¼” metal.

Process: Short circuit MIG (GMAW)
Welder: Lincoln SP-250
Gas: 75% Ar 25% CO2
Wire: .035” Lincoln L-56 (ER70S-6)
WFS: 316 IPM
Voltage: 19.4 volts
Shielding Gas: 25 CFH
CTWD: 5/8” – 3/4”

20. Inside Corner weld on strut

[Don52]

For the outside corner weld, I used the same settings as the groove weld shown above.

21. Outside corner weld on strut


I just barely overlapped the cap to the end of the tube.

22. Tube cap tacked


23. Tube cap welded


I bought a cylinder of 90% Argon 10% CO2 so I tried a sample weld on some scrap. Below are my settings. I would have liked to use a higher WFS, but my welder would give me overcurrent warnings for anything equal or above 400 IPM even though it went to 500 IPM. Just for reference:

The Miller Calculator recommends:
400 – 420 IPM WFS @ 24 – 25 volts

The cut sheet for the .035” Lincoln L-56 wire recommends:
375 IPM WFS @ 23 volts
or
500 IPM WFS @ 29 volts

Process: Spray transfer MIG (GMAW)
Welder: Lincoln SP-250
Gas: 90% Ar 10% CO2
Wire: .035” Lincoln L-56 (ER70S-6)
WFS: 375 IPM
Voltage: 27.5 volts
Shielding Gas: 30 CFH
CTWD: 3/4” – 1”

24. Spray transfer test


I chose the spray transfer process to weld the ½’ plates onto the tubing, because I don’t like to use short circuit MIG for anything over ¼” in thickness.

25. Caster plate fillet weld

[Don52]

It is a very hot process as evidenced by the heat tint on the far side of the ½” plate.

26. Caster plate heat tint


The next step was to weld the diagonal braces to the struts.

27. Diagonal gusset welded to strut


28. Struts all done


I used my Fireball squares to set up the frame for welding. I left a ~3/32” root gap at each corner for better penetration.

29. Frame clamped up


30. Frame tack welded

[Don52]

I used the short circuit process for the 1^st root pass.

31. 1st pass on corner


I noticed that the joint wasn’t entirely filled so I went over it with the spray transfer settings.

32. Cover pass on corner


I again used the fireball squares to setup for welding the struts to the frame.

33. Strut clamped to frame


34. Strut welded to frame-1


35. Strut welded to frame-2

[Don52]

For some of the fillet welds between the struts and the frame I used the dual shield process. This is my go-to process for MIG welding thicker metal in my shop, particularly for out of position welding. My Lincoln 210 MP welder can handle the .035” dual shield wire fine, but it is a little wimpy to handle the .045” dual shield wire.

Process: Dual Shield flux core (FCAW-G)
Welder: Lincoln SP-250
Gas: 75% Ar 25% CO2
Wire: .035” Lincoln 71M (E71-T1M)
WFS: 375 IPM
Voltage: 23.6 volts
Shielding Gas: 30 CFH
CTWD: 3/4” – 1”

These settings are close to the settings on the Lincoln cut sheet for this wire:
350 IPM WFS @ 23-26 volts
or
400 IPM WFS @ 24-27 volts

Here is a link to a Welding Tips and Tricks video in which JD Brewer used the same settings that I used, except that he used it on a 3/16” wall thickness tubing frame. It may be counter intuitive, but I have found that these hotter setting actually work better for vertical up dual shield welds. JD did mention in the video that he prefers .045” dual shield wire for ¼” wall thickness frames. I have just purchased knurled drive wheels for my SP-250 welder so I can run .045” dual shield wire on it. I will see how it works out.

https://www.weldingtipsandtricks.com...ield-rack.html


36. Dual shield fillet weld


I chamfered the edge of the ½” plate to ensure that I had good penetration on both the ½” plate and the ¼” tube. I also used the spray transfer the process for both 1st and 2^nd pass to help with penetration. Note: I could have used the dual shield process as well, but I was worried about the duty cycle of my 210 MP welder for the 16 one foot long welds. The SP-250 handled it with no problems, in fact the fan on the welder only turned on for 30 seconds once in a while.

37. Joint for bottom plate


38. 1st pass on bottom plate


39. 2nd pass on bottom plate


As I added more parts to the fabrication, so it got heavier. Eventually I needed to use my engine hoist to help me to flip the fabrication.

40. Using engine hoist to manipulate the fabrication

[Don52]

Here is the setup that I used to weld the leveling feet to the frame.

41. Leveling foot setup


42. Leveling foot close up-1


43. Leveling foot close up-2


Here is a dual shield weld of the 1” thick leveling foot. For this picture I left the slag on.

44. Leveling foot welded


Here is a picture with the slag removed.

45. Slag chipped from leveling foot

[Don52]

Here is the back side of the ¼” leveling foot brace plate that was welded in the previous step. The heat tint indicates that the dual shield process threw a lot of heat into the plate.

46. Heat tint on leveling foot brace


Here is the caster base all welded up.

47. Caster base all welded


The next step is lifting the 1,800 lb cutter grinder and lowering it onto the new caster base to try it out, to make sure that it fit. I felt that it would be much easier to make adjustments to the fabrication, before the caster base was painted. Below is a picture of the SolidWorks assembly model of the lug that I designed to be welded to the bottom of the I-beam in the ceiling as well as the shackle.

48. Lifting Lug


Here is a picture of the lifting lug machined.

49. Lifting Lug machined


I wanted to verify the dual shield parameters so I welded up some scrap for a cut and etch test. The plate is 1” thick.

50. Dual shield test sample

[Don52]

Here is a cut through the sample weld.

51. Cut etched and polished


And here is a close up of one of the welds.

52. Cut etched and polished closeup


Here is a picture of my setup for welding the lug on the bottom of the I-beam. Notice the following:
- Lally column that was used to support the weight of the attic.
- Bar clamp to give me something to rest my arms on.
- Piece of bare welding cable supported by a rare earth magnetic, for my work lead.

53. Lug welding setup


Here is a close up of the same thing.

54. Close up of Lug welding setup


The next step was to attach the shackle and the ratch come along to the lifting lug.

55. Ratcheting come along installed

[Don52]

56. Detail of lifting lug


I used the ratcheting come along to lift up the cutter grinder so that I could remove the temporary caster base from the bottom.

57. Lifting cutter grinder from temporary base


I lowered the cutter grinder on to the caster base to make sure that it fit.

58. Cutter grinder test fit on new base


I lifted the cutter grinder off of the new caster base and primed and painted it.

59. Cutter grinder base primed and painted


60. Close up of painted Cutter grinder base

[Don52]

After the paint dried, I lowered the cutter grinder on to the new caster base.

61. Cutter grinder on base and in place


And it does look like it was always there.

-Don

[MMW]

Exceptional work and attention to detail. Better than any factory setup.

[Don52]

Exceptional work and attention to detail. Better than any factory setup.

Thank.

Do you know how I can contact a moderator so that my post with pictures 36 - 40 can be approved?

I don’t think that there was anything inappropriate, but I did have a link to one of Jody’s Tips and Tricks videos in the post. When I attempt to edit the post it says that I don’t have permission to edit my own post.

-Don