# DIY Riser Block for 6" x 26" Import Mills (Grizzly, Enco, Harbor Freight, etc.)



## Tmate

A lack of distance between the spindle and table appears to be a universal issue for owners of these popular import mills. I think I may have come up with a relatively easy to fabricate riser block to fix the problem.

McMaster-Carr carries a 6" dia. pipe flange (Pt.#68905K389) that is almost made to order for this riser block project. They are 6" in diameter, 3/4" thick, with a 3.10" x 1/4" flange on one side. They come with four 3/4" bolt holes, two of which will be used for dowel pins for alignment purposes.  A third will be used for one of the hold-down bolts.  Two 1/2" diameter holes will be drilled in each plate for the other two hold down bolts.  Additional detail is included in the second image below.

They cost approximately $26.00 each, and with slight modification, will stack pancake style to whatever height you desire. The machine work necessary is:

Drill two 1/2" holes in each plate
Mill or face the flange off all but one plate
Bore the existing center hole in one plate to 3.10"
Cut to length two 3/4" dowel pins (drill rod or CR round)

I'm waiting for warm day to install it. There may be some minor dimension differences in these mills depending on name brand. It's a good idea to check dimensions on yours before going too far.


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## Mitch Alsup

The nose hieght problem is the main reason I went for a 8×30 (G0730) instead of the 6×26.


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## mattthemuppet2

that's a really neat find! I got a couple of 6" diameter 4" tall things (pulleys?) off ebay a while back that I'm going to turn into a riser for my 6x26. Just waiting to finish my SB9 reassembly before I start  Please post details of yours!


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## buddy3223

I also plan to put a riser block on my 6x26. I am undecided whether to make it out of solid piece or go the route you describe. Your method is really inviting as it would be much easier to obtain the material. I am undecided how high I want to raise it. I really need to find out if both sides of the machine surfaces are flat with no raised areas. I have never removed the power head from unit, so I have no idea what is underneath. Thanks for the post I will be watching for details.


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## Tmate

There are some pictures on line with the heads removed -- both the top of the base and the bottom of the head.  There may be variations in dimensions from machine to machine, however.  I'm going to wait until I get my head off before doing any final machining.

I've removed the head using my engine hoist a couple of times when I moved - of course I never took measurements.  The angle of the boom complicates matters, plus my mill is now sitting in a corner.  I'm building a small lift to straddle the machine and raise the head.  It will use my cable puller and a couple of pulleys.  When I am finished, I will put casters on the bottom and use it to lift heavy items from the floor to workbenches in my shop.

Below are a couple of shots of a mill head being removed, also a rough drawing of the lift, which will sit on the mill's bench and straddle the mill.  The cable puller will attach to the side, with the cable going through the pulleys.


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## higgite

I’m not familiar with that mill, but curious (nosy?). I don’t see any obvious (to me) adjustments for head nod and tilt in the pics. Does it have such adjustments like the Bridgeports that I’ve seen, or will you need to shim the risers or make other adjustments to tram it? 

Also, will the surface friction between the riser layers be enough to keep them from moving relative to each other during heavy cuts and such? Are you sacrificing rigidity for space or will it have an insignificant effect?

Tom


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## Tmate

No forward & backward adjustment, but there is a side to side tilt adjustment.  There will be thee 3/4" dowel pins going snugly through all the plates, in addition to the bolts.  I may be sacrificing some rigidity for space, I won't know until I am finished.  Others with riser blocks have reported no loss of rigidity.  I would imagine a solid block would be more rigid, but would present machining difficulties for me.  I have plenty of rigidity now, so I'll have to wait and see.


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## buddy3223

Thanks Tmate for the pictures, that answers some of my questions. I will try to find what the dimensions will be. As far as a nod adjustment, my machine was only out a very minor amount and was corrected with a shim. I will be able to raise the power head with overhead lift.


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## mattthemuppet2

here's another way to do it, with dimensions:





						Riser Block For a Grizzly G3103 Milling Machine - Shop Floor Talk
					

Riser Block For a Grizzly G3103 Milling Machine Machining



					www.shopfloortalk.com
				




I'll be making mine so that the bolts go all the way through into the t-nuts in the base. I have 4 or 5ft of allthread (M10x1.??) so that I can reuse both the t-nuts and the acorn nuts at the top. The allthread will be captured by the riser so it will rotate with the head.


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## Tmate

It was pointed out to me that I transposed two numbers in the part number i provided above,  The part number shown in the drawing is the correct one: Pt.#68095K389


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## Neurotic-Hapi-Snak

Not to be a spoil sport, but you can buy a 6" dia, 12" length piece of ductile cast iron for $200 from McMaster-Carr, that's enough to make a riser plus a spacer to move the head away from the column further.


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## Tmate

Neurotic-Hapi-Snak said:


> Not to be a spoil sport, but you can buy a 6" dia, 12" length piece of ductile cast iron for $200 from McMaster-Carr, that's enough to make a riser plus a spacer to move the head away from the column further.


 
Just trying to come up with a new way of attacking the problem.  I like doing that.


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## Neurotic-Hapi-Snak

Would just hate for you to spend all that money when you could do it a better, easier way, for about the same. Plus I thought those were the standard cast steel flanges.


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## Shootymacshootface

higgite said:


> I’m not familiar with that mill, but curious (nosy?). I don’t see any obvious (to me) adjustments for head nod and tilt in the pics. Does it have such adjustments like the Bridgeports that I’ve seen, or will you need to shim the risers or make other adjustments to tram it?
> 
> Also, will the surface friction between the riser layers be enough to keep them from moving relative to each other during heavy cuts and such? Are you sacrificing rigidity for space or will it have an insignificant effect?
> 
> Tom


I was curious about this as well, until I watched a Stefan Gotteswinter were he trammed in an RF25 clone using epoxy. I guess the conventional method is scraping in the base where the column bolts to it.




The spacer is a great idea, but if you can't get it trammed in pretty close, you can forget about using a fly cutter.


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## Neurotic-Hapi-Snak

Shootymacshootface said:


> I was curious about this as well, until I watched a Stefan Gotteswinter were he trammed in an RF25 clone using epoxy. I guess the conventional method is scraping in the base where the column bolts to it.
> 
> 
> 
> 
> The spacer is a great idea, but if you can't get it trammed in pretty close, you can forget about using a fly cutter.


Plus you'd be adding in 12 more mating surfaces that could add error rather than two with a solid riser. Quick and dirty is to use shims, proper way is to scrape both surfaces so that they not only match each other but are perpendicular to the axis of rotation. That way you won't have any error show back up when you rotate the head.


mattthemuppet2 said:


> here's another way to do it, with dimensions:
> 
> 
> 
> 
> 
> Riser Block For a Grizzly G3103 Milling Machine - Shop Floor Talk
> 
> 
> Riser Block For a Grizzly G3103 Milling Machine Machining
> 
> 
> 
> www.shopfloortalk.com
> 
> 
> 
> 
> 
> I'll be making mine so that the bolts go all the way through into the t-nuts in the base. I have 4 or 5ft of allthread (M10x1.??) so that I can reuse both the t-nuts and the acorn nuts at the top. The allthread will be captured by the riser so it will rotate with the head.


The problem with that design is you're sacrificing quite a bit of rigidity by using a 3" diameter pipe rather than a 6". Best design would be to use a riser of 6" (or more) in diameter with the bolts going from the turret to the column through the riser. That way you put the riser in compression and the bolts into tension, limiting how much each can flex.


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## Tmate

Shootymacshootface said:


> I was curious about this as well, until I watched a Stefan Gotteswinter were he trammed in an RF25 clone using epoxy. I guess the conventional method is scraping in the base where the column bolts to it.  The spacer is a great idea, but if you can't get it trammed in pretty close, you can forget about using a fly cutter.





Neurotic-Hapi-Snak said:


> Would just hate for you to spend all that money when you could do it a better, easier way, for about the same. Plus I thought those were the standard cast steel flanges.



I realize this is a somewhat impractical exercise, and for me the fun is trying something new.  If it doesn't work, I'm out about the cost of a couple of meals in a good restaurant.  I can easily pull the flanges back out and the mill will be none the worse for it.

There have been many approaches to making these risers.  The most common, of course, is to machine it from a solid round bar.  Others have welded flanges onto either end of a tube.  Some have used individual tubes between end flanges.  I don't know of anyone who has tried this method.  It may well not have sufficient rigidity.

The flanges will all be pinned rather tightly together with 3/4" drill rod passing snugly through their original bolt holes.  I'm hoping this, plus the weight of the head, plus the clamping of the three bolts will hold it firmly.  There is no head nod adjustment on these mills, just side to side.  I could possibly work one of the flanges lightly to tram the nod.


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## Neurotic-Hapi-Snak

Best way would be to face them all off, ream the holes to a precise size, e.g. 25/32" or 49/64" , but slightly under sized. Then either heat each flange till you can fit a rod of the correct diameter through and allow them to cool and contract on the rod, or you could use a press to force the rod in. You want to make it so they effectively become one piece, thereby eliminating all those mating surfaces. Or you could weld them together. Then you want turn or mill the top and bottom faces so they are parallel.


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## mattthemuppet2

Neurotic-Hapi-Snak said:


> The problem with that design is you're sacrificing quite a bit of rigidity by using a 3" diameter pipe rather than a 6". Best design would be to use a riser of 6" (or more) in diameter with the bolts going from the turret to the column through the riser. That way you put the riser in compression and the bolts into tension, limiting how much each can flex.



I linked that build thread as it's a good source of dimensions without having to take the top of your own mill off  I'll be making mine with a piece of  1/2" thick 6" OD and 4" height flat belt pulley (if that's what it is!) that I'll weld a piece of 1/2" round to. All thread to go through it into the t-nuts in the main casting.


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## Neurotic-Hapi-Snak

Another thing to consider is material choice. Although steel is easier to source, it doesn't dampen vibration like cast iron, so a riser made of steel would only dampen vibration through mass alone. Dampening vibration is important for machine tools, especially small ones that lack mass.


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## jwmelvin

But remember too that the bolted joints of a riser will also themselves absorb vibration. Although it’s hard to say the relative effect of that versus material choice (and they are not mutually exclusive), the damping from bolted joints can be quite significant.


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## Tmate

For all the theory, all of it good, the only way to be sure is to try it.  Or, since I lack large enough equipment to machine one from a solid block, I could pay a local machine shop to do it.  Where's the fun in that?


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## Mitch Alsup

Neurotic-Hapi-Snak said:


> The problem with that design is you're sacrificing quite a bit of rigidity by using a 3" diameter pipe rather than a 6". Best design would be to use a riser of 6" (or more) in diameter with the bolts going from the turret to the column through the riser. That way you put the riser in compression and the bolts into tension, limiting how much each can flex.



In the same material and wall thickness:: the 6" riser is 8× stiffer than the 3" riser.
In the same material and solid:: the 6" riser is 16× stiffer than the 3" riser.


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