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Powermatic 3520B riser blocks.

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Hi,
Are there commercially available riser blocks. I'd like to add 2" under the head and tailstock.
Also, what are the downsides of riser blocks. What about the tool rest? What are the options?
is there anything else I need to know?
Thanks
Rob
 
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If you add 2" to the headstock and tail stock, you'll theoretically increase the swing by 4" overall. Not only will the tool rest posts be required to be 2" longer, but the banjo may not stabilize the tool rest as well as it did with the original swing. If so, the banjo might need replacement, too. Another thing to consider, is the belt will likely need to be replaced with a longer one, which means the spindle will have to be removed. You might as well consider having to replace the headstock bearings, as long as you have to remove the spindle shaft anyway.

Riser blocks were available for my Woodfast lathe at one time, and I considered it, but I gave up on that upgrade. My thinking on that was as long as I had to consider all of the above, I might as well just go ahead and buy another lathe!

-----odie-----
 
Last edited:
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Another option is setting the headstock up for outboard turning and mounting another lathe bed-way onto your existing lathe at a lower height, the only modification you need is the correct tailstock assembly or riser block under the tailstock to align to the outboard headstock. If you are not needing to turn long pieces you can mount a short bed extension on one end of the lathe to support your banjo at any height to turn larger diameter pieces, you just need
to drill and tap or modify the mounting on your lathe legs to secure the bed extension to the lathe legs securely.
 

john lucas

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There isn't a commercially available riser. YOu could make your own. I did that for a Nova 16" lathe. The hard part is the tailstock locking mechanism. If your a machinist no problem but if not it's quite challenging. As for the banjo you could simply make your own tool rest with longer tool posts. That's what I did for the Nova. I made my riser blocks out of MDF and it probably added to the vibration a little. If you made the riser blocks out of metal with a good clamping mechanism it should work. Or you could simply sell that lathe and buy the Powermatic 2442 which would be a better option.
 
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There isn't a commercially available riser. YOu could make your own. I did that for a Nova 16" lathe. The hard part is the tailstock locking mechanism. If your a machinist no problem but if not it's quite challenging. As for the banjo you could simply make your own tool rest with longer tool posts. That's what I did for the Nova. I made my riser blocks out of MDF and it probably added to the vibration a little. If you made the riser blocks out of metal with a good clamping mechanism it should work. Or you could simply sell that lathe and buy the Powermatic 2442 which would be a better option.
My intent is to be able to occasionally turn larger bowls and platters. I thought about getting a larger lathe and considered a 2442 or a Robust. I'm discouraged by the additional $4-5,000 cost of a new machine.
I do have access to a machinist at reasonable cost and I could possibly buy a tool rest made for a 24" lathe. I have tinkered with machines before and have sometimes been disappointed with the process or results. I was hoping to find someone who can provide what I need as an after market item.
 

Dave Landers

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There is available a bed extension for around $500 that can also be mounted low to give you something like a 38" swing for faceplate turning. Includes post extension for the tool rest, but doesn't raise your tailstock, so maybe not exactly what you're looking for.

.
That's for the 2020, but the 3520B one is similar - I include that link because the picture includes the tool rest post
 
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There is available a bed extension for around $500 that can also be mounted low to give you something like a 38" swing for faceplate turning. Includes post extension for the tool rest, but doesn't raise your tailstock, so maybe not exactly what you're looking for.

.
That's for the 2020, but the 3520B one is similar - I include that link because the picture includes the tool rest post
thanks but ill need rough out heavy natural edge blanks, so ill need to use the tailstock.
 
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Well, you may need all new tool rests, and/or a new banjo to go with the higher clearance. Not sure, but also, are the bearings designed for that size of blanks? I would at least check what they use on the 4224. Banjo shouldn't present any problems. You may want a bigger pressure plate under the headstock as well. With my Beauty, and I don't know if this has changed, the pressure plate on it is the same size as the footprint of the headstock, which I think is a good idea. For turning pieces the size you want, I would prefer a lathe with 3 speed ranges. My AB had that, but that is no longer available. It does come on the Vicmark and Oneway lathes.

robo hippy
 
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I may have missed something, but I have an external PM floor stand and use that with the blank mounted on the headstock that’s been relocated to the tailstock end of the lathe. With the tailstock removed and a large enough faceplate you can “theoretically” turn a platter as big as you want ( the floor is the limit). Mine is an A model but should work on 3520B. The floor stands aren’t cheap but a lot less than another lathe.
 
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If you add 2" to the headstock and tail stock, you'll theoretically increase the swing by 4" overall. Not only will the tool rest posts be required to be 2" longer, but the banjo may not stabilize the tool rest as well as it did with the original swing. If so, the banjo might need replacement, too. Another thing to consider, is the belt will likely need to be replaced with a longer one, which means the spindle will have to be removed. You might as well consider having to replace the headstock bearings, as long as you have to remove the spindle shaft anyway.

Riser blocks were available for my Woodfast lathe at one time, and I considered it, but I gave up on that upgrade. My thinking on that was as long as I had to consider all of the above, I might as well just go ahead and buy another lathe!

-----odie-----
On 3520B the motor is direct mount to headstock so raising the headstock will not affect the belt or motor. Motor is mounted slightly below the spindle so the belt is rather short also but still all contained in the headstock with motor in line but below spindle.
 
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I may have missed something, but I have an external PM floor stand and use that with the blank mounted on the headstock that’s been relocated to the tailstock end of the lathe. With the tailstock removed and a large enough faceplate you can “theoretically” turn a platter as big as you want ( the floor is the limit). Mine is an A model but should work on 3520B. The floor stands aren’t cheap but a lot less than another lathe.
Jerry, sorry I didn't explain fully. I have some 24" diameter cherry blanks about 15" deep that weigh about 200 lbs each. I'm afraid to rough them out on a faceplate at the end of the lathe.
 
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On 3520B the motor is direct mount to headstock so raising the headstock will not affect the belt or motor. Motor is mounted slightly below the spindle so the belt is rather short also but still all contained in the headstock with motor in line but below spindle.

OK, got it......I was thinking it was similar to my Woodfast...

-----odie-----
 

hockenbery

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Jerry, sorry I didn't explain fully. I have some 24" diameter cherry blanks about 15" deep that weigh about 200 lbs each. I'm afraid to rough them out on a faceplate at the end of the lathe.
i occasionally have people in my club call and ask if they can use one of our 24” lathes to turn a piece they can’t fit on their lathe. It’s always a fun afternoon.

if you know someone with a big ONEWAY. Big Robust or similar give them a call.
if turning 2 satisfies your desire to turn a big piece then you won’t need a bigger lathe.
if it increases Your desire to go big, you’ll find a way to get a bigger lath.
 
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I've found the "wow" factor wears off real fast on large platters or bowls. About 6 years ago I turned a couple of platters 18" plus and a bowl about 17". Yep, new big lathe. I couldn't give them away to friends after we sat and talked awhile. Pretty sure they were thinking "where would we put that". An 17" X 8" bowl sitting on a coffee table is quickly overpowering. After a few months they all migrated to the door leading to the garage. Selection of wood becomes more important in larger sizes.
 
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@Joe: Had the same experience. One order on at 15" plate for *the* special place in his office. Not sold one single plate or bowl plus 14" since then and stopped turning any more.
 
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Anything is possible if you have enough $$$$'s or the right friends.

My friend has a Powermatic 90 and wanted to increase the swing to 20". Part of the desire was to have an old made in the USA lathe that could keep pace with newer machines. He made aluminum riser blocks. He is a beginner machinist but did a great job. The next problem was to extend the belt cover. I told him to cut the belt housing in half and I would weld in a 4" spacer. Worked well and he did the body work to fair in my weld so it looks factory. Final problem was the banjo. I told him to call Kevin at Oneway. Kevin solved that problem most quick.

Picture of the result before we reinstalled the spindle along with all new bearings.

IMG_4316.JPG
 
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Thanks for all the great responses and good points about turning large bowls and platters as a temporary or one time thing. I have a machinist next door who I will ask what he would charge to fabricate the blocks, if its prohibitive I may pass. I hate to cut fresh 24" cherry blanks down to 20". Any thoughts about steel being better to absorb the vibration that aluminum?
 
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When I have wide logs like that, I generally try to center the bigger bowls, and plan for taking spindle blanks off of the sides. They are good for boxes, rolling pins depending on wood, and any other type of spindle you can think of. I do end up, most of the time, with more than I can use, but they always go at the club wood raffle. The center cut/quarter sawn part makes for good plate blanks. Take two to 4, 1 1/2 inch thick slabs out of the center. Funny thing about plates, if I have them, they don't sell well. If I don't have them, every one wants them. I also can take smaller bowl blanks out of the sides. I, and those who buy them don't really seem to care if the grain is perfectly centered. The rest of the scraps get burned...

robo hippy
 
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