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Getting a Rise

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RJSakowski

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#1
I have a Grizzly G0602 lathe. One of my issues has been the clearance beneath the bed. It makes it difficult to clean chips from the chip tray. Another concern was the inability to access the two lower mounting nuts on the motor.

I decided to put two 1" risers under the lathe. My lathe stand has a welded steel frame with a single piece of 7" channel running under the lathe. The lathe bolts through the chip tray and sheet metal skin and through the center of the 3/16" channel web. This scheme is fairly rigid but allows some flexing. I decided to use 5" x 7-1/2" pieces for the riser which fairly well bridges the web. I used four 3/8"-16 bolts on a 3-1/2" x 6" bolt pattern for mounting to the stand. The risers were tapped to receive those bolts. The lathe was fastened to the risers with 1/2" 13 bolts into threaded holes in the risers.

The most difficult part of the project was cutting the blanks from a 10" x 31" - 75 lb. chunk of plate. My oxy-acetylene tanks need refilling. Besides that, an O/A cut leaves a bead of hardened steel at the bottom of the cut which has to be ground away before any machining of the edge. Not having a chop saw, I purchased a 7" cutoff disk for my Craftsman circular saw. It took about 20 minutes to push my way through the 10" of cut but it left a clean edge not requiring further machining. I took the now 22 lb. chunk of steel into the shop and cut it in half by mounting it vertically in my horizontal band saw and cutting from either side. I cleaned up the last edges on the mill but the other three surfaces were acceptable for this use.

The lathe mounting holes were drilled and tapped to match the lathe footprint. The stand mounting holes were drilled 5/16" for tapping but not tapped yet as my plan was to use the riser as a drill guide for drilling the holes in the stand. I unbolted the lathe and using time honored method of levers, lifted the the onto 3" of stacked 2" x 4" cribbing. This allowed me to move the lathe around for access to the riser locations. I bolted the risers to the stand, using the tapped hole and a bolt from the bottom of the stand. I then drilled the eight 5/16" holes through the top of the stand, removed the risers and drilled the eight holes out to 21/64".

I then tapped the eight holes for the 3/8"-16 bolts. The plates were then mounted to the stand, using four 3/8"-16 x 1" bolts and washers. With the risers in place, the lathe was lowered onto them and bolted to the risers with 1/2"-13 x 1" bolts and washers.

Once the lathe was reassembled, I checked my cross feed for perpendicularity to the spindle axis. To do so. I mounted a domed 1/2" bolt and nut in one of the slots in my faceplate at 3-1/2" from the center. I then placed a dial indicator on my cross slide and zeroed it with the domed bolt nearest the front and horizontal with the lathe centerline. I then rotated the faceplate 180º and moved the cross slide to intersect. I measured the difference at .00035". Since I was planning some more work on the stand, I decided to leave it at that. I then mounted a 1" bar in the chuck and, using Rollie's Dad's Method, measured the taper at .00035" in 10" The taper error was in the same direction as the perpendicularity error which told me that my headstock was out by .00005"/" (.00035/7) and my taper error attributable to bed twist was .000015"/". This is good news as it indicates that the lathe will need a slight tweak if the headstock and little, if any, shimming.

I can now access the motor mounting nuts with a 1/4" drive and wobble extension, although it is still tight. I can easily get under the bed to brush out chips or retrieve lost parts now. Finally, the plate provides an excellent surface for mounting the lathe.

No picture of the actual risers. I dropped my smart phone before transferring them and totally trashed it. Here is a drawing of the riser and photos of the final install.
602 Headstock Riser.JPG
602 Headstock .JPG
602 Tailstock .JPG
 

Rickwjenn

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#2
What a cool project. That is some serious steel plate to cut. The end result looks great and I can sense how the extra 1.0" gets you the access you needed.

Did you drill/tap the riser from the top thru the lathe feet and then bolt in on? That looks like it was pretty tight but since you said cutting the 1.0" plate was the hardest, this must of been easier (relatively speaking of course..)>
 

RJSakowski

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What a cool project. That is some serious steel plate to cut. The end result looks great and I can sense how the extra 1.0" gets you the access you needed.

Did you drill/tap the riser from the top thru the lathe feet and then bolt in on? That looks like it was pretty tight but since you said cutting the 1.0" plate was the hardest, this must of been easier (relatively speaking of course..)>
I squared the plate up on my mill drill and visually found the location of the 1/2-13 hole and zeroed the DRO and used a center drill to spot the five holes. Then, I moved the plate to the drill press and drilled all five hole through with a 5/16" drill bit. I could have used a backing plate and drilled on the mill/drill but since I was going to drill the holes in the stand, using the plate as a drill guuide, before tapping the 3/8-16 holes, I wouldn't have saved any time.

I then went to the mill/drill and, using a 5/16" dowel pin, centered the hole for the 1/2-13 tapped hole on the spindle and over a slot on my table, clamped it, and drilled the 29/64" tap hole. While the plate was still clamped, I tapped it for 1/2-13, using a tap guide. Although it is more involved, I prefer to tap my holes like this as I am certain that the tap is centered and square with the drilled hole. It results in a cleaner hole and since using this procedure, I have never broken a tap.

Next, I went ti the lathe stand and mounted the plates using a 1.2-13" bolt from the bottom side. I used a straight edge to position the front edges of the plate so they were in line. I tightened the 1/2' bolt and drilled the eight 5/16" holes in the stand, removed the plates and drilled them to the 25/64" clearance diameter. As I drilled each hole, I dropped a 3/8" x 3" bolt in the hiles. This is just a precaution to guard against any movement of the plate between holes. With the 1/2" bolt securing the plate it is really belt and suspenders. It's a habit that I got into years ago when I needed perfect alignment of a set of mating holes.

Next, I moved back to the mill/drill and, using the same technique as for the 1/2"-13 holes, tapped the 3/8"-16 holes. I was then ready for assembly.

I used the mill/drill because of precision placement of the mounting holes but it could have been done with a hand drill on the lathe stand. I would have laid out the hole locations and center punched them. If a drill press was available, I would have drilled the four corner holes to 5/16" and drilled and tapped the 1/2-13 hole. without a drill press, I would have drilled and tapped the 1/2-13 hole on the workbench, fastened the plate to the stand, and drilled the 5/16" holes. Given that I was hand drilling, I probably would have drilled a pilot hole with a 3/16" drill first. I would then pop the plates and drill the clearance holes and tap the 3/8"-16 holes from the bottom of the plat. From the bottom because of of a reduced chance of misalignment due to a a wandering tap. If the stand could be flipped, I would have left the plate in place and drilled the stand for 3/8" and tapped the holes As each hole was tapped, I wouldinsert a bolt and tighten. This would assure near perfect registration of the tapped hole with the hole in the stand. Since my lathe was still on the stand, this wasn't possible for me.
 

Rickwjenn

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#4
Thanks for all the information. You planned this project out exactly - very impressive. Flipping the stand would of made it alot easier but doing that is another issue.
 

Mitch Alsup

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#5
Is there any reason steel is preferred over aluminum for this application?
 

RJSakowski

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Thanks for all the information. You planned this project out exactly - very impressive. Flipping the stand would of made it a lot easier but doing that is another issue.
Yes it would have but unfortunately, I have no sky hook over the lathe. I did put a sky hook in the center of the room for the express purpose of lifting the lathe onto the stand but it would involve moving a foot shear and a large tool cabinet to access and walking the lathe and stand across the floor with pry bars. It's always more difficult in a tight space.
 

RJSakowski

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Is there any reason steel is preferred over aluminum for this application?
I used steel for a couple of reasons. First, I had the steel and would have had to purchase new aluminum stock. Second, I prefer steel to other materials where precision alignment is involved. Aluminum has a tendency to cold flow and while it isn't great, it could alter the alignment. Even worse are plastic an fibrous materials.

If I had the aluminum and not the steel, I might have gone that route though.
 

RJSakowski

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In the first post, I said that I trashed my old cell phone readout in the process. Not a big deal since the Li ion battery had swelled to the point of looking like a pillow and the case and carrier were bulging as a consequence. I could have repaired it but the best cost for replacement parts on eBay would have been less than the cost of a new Android tablet.

I bought a new Android tablet and it works well. A 50% larger display is welcome to these tired old eyes and all the touch controls are available without scrolling. But now I needed a stand for it. While I could have done the machining by writing a CNC program, it weas simple enough that manual machining would suffice.

I decided to use some epoxy composite material the I had on hand. It was reject material from a company that I used to work for and while it doesn't have the best mechanical properties, it is well suited for this purpose, however. The material contains calcium carbonate, powdered limestone, which is abrasive to HSS so I elected to use carbide router bits for the milling.

I designed the tablet holder with a pocket to capture it and rather than purchasing A Tee slot cutter, I decided to use a two piece design with a front bezel epoxied to a backplate. The backplate was squared up first, leaving some excess.. It was then mounted in the milling vise with the moveable jaw in the secondary position. The interior pocket and side boss were milled using a 3/4" router bit with a 1/2" bit used to finish the corners. The two side were also finished. A 3/8" end mill was used to cut a slot for the power cable.
DRO Backplate Drawing.JPG

The dashed lines are my toolpath extents for clearing the pocket

Another piece of the composite material was roughed out with the band saw and epoxied to the backplate. When the epoxy had cured, the assembly was again mounted in the vise and the bezel interior and exterior profiles were cut to size using the 1/2" bit. A bit of hand blending and braking sharp features completed the holder.

The mounting bracket consisted of three pieces, a flat steel bar that mounted to the lathe backsplash, a 3/8-16 bolt welded to the bar and an aluminum bracket that mounted to the holder. I chose this approach because the composite material isn't strong enough to provide a robust connection for a single 3/.8" bolt.

A piece of aluminum was squared up to 3/4" x 1" x 4". A 5/16" hole was drilled and tapped for the 3/8-16 bolt and two holes for 10-24 screws were drilled and counterbored with a 5/16" endmill to 1/4" depth. I drilled the holes to the tap drill size rather than the clearance size because my plan was to use the bracket as a guide for drilling and tapping the mating holes in the holder. Then I rotated the bracket 90º and drilled the two remaining holes to the 10-24 tap drill size.

The next step was was to cut the rabbet which formed the seat for the holder, using a 3/4" endmill. The final operation was to cut the two bevels. This could have easily been done on the CNC. It could also have been done by mounting the vise at the correct angle and side milling. Instead, I chose to face mill by mounting the work at the correct angle. To set the angle, I cut a gage out of a piece of aluminum sheet and place under the edge of the work as I tightened the jaws. Because the workpiece clamping was minimal, I used light passes.

With the bracket finished, I turned to mating it to the holder. While I could have positioned the holes with the DRO, it would have involved finding multiple edges on two different surfaces. It was much easier to use the bracket holes as a drill guide. The holes were drilled for 10-24 tapping and the bracket drilled for clearance and the holes tapped. With the first set of holes drilled and tapped, socket head cap screws were used fasten the two pieces together and the second set of holes drilled and tapped. This process is somewhat lengthy but it ensures that all four holes a fully registered.

The final process was painting the steel flat black and applying automotive clear coat to the holder and upper bracket.
DRO Bracket 2 .JPG

The bracket mounting detail. The two sets of screws at right angles provide a secure mount without relying on thread strength in a weak material.

Lathe DRO 1 .JPG

The assembled DRO holder.

Lathe DRO .JPG

The holder with DRO in place and mounted on the lathe.
 
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