Blocking up a Lathe

[Dan Mosley]

I discussed with a friend that was looking for a lathe the possiblilities of blocking up a lathe he was looking at buying to increase the capability of turning larger diameter pc's of wood. I have a Jet 1642 EVS - 16" - 2hp - and he was looking for one similar. I looked at mine close and I think it can be done but I would want a machinist to make the blocks. He would have to block up the head stock, tail stock and make a tool rest or tool rest extension. The part that may be costly is the machining work but this seems to be a better approach then sliding it to the end of the ways and making a free standing tool rest.
Question that I was asked was if the blocks were say 6" (16" - 2" due to tool rest height + 6" = 20" max - plenty capacity). How would you turn if the height was raised like that - build a wood stand and step on it - it would not be used all the time just when you wanted to do a large log.

Of course if its to costly to do then the idea would be scrap........................................Thoughts from anyone thats done it ?

 

[Joe Greiner]

Using the wood stand only for large logs doesn't seem enlightened. For smaller logs, I think you'd still want the axis near elbow height. The wood stand should be extensive enough to preclude accidentally stepping off, e.g. for sharpening or retrieving a tool.

If I were doing this, I'd build a new stand for the lathe itself to lower the axis to a comfortable height.

 

[Bill Boehme]

Dose of reality

I hate to be a party pooper, but perhaps your friend should either decide that he likes the idea of turning off the end of his lathe or start saving his pennies for a lathe that scratches his itch.

For starters, there is no such thing as off-the-shelf six inch thick blocks of steel. If you get a second mortgage you might get a foundry to make a special order block of cast iron and then get a second job to pay for the design services of a machine shop to modify your lathe design so that headstock and tailstock would still be able to slide and be locked down. The actual machining would necessarily include boresighting the headstock and tailstock with respect to the lathe bed for precision alignment. The lathe will need new sturdier legs since the "spacer" under the headstock will add a bit over 135 pounds and the one under the tailstock will add a bit over 80 pounds. The good news you may hear from the machine shop is that you could save a few thousand dollars by making the headstock fixed. Yay, who needs a sliding headstock anyway.

What's so bad about turning off the end of the lathe? The type of outboard toolrest used on the Robust American Beauty and VB36 lathes are rock solid and anchored to the lathe structure. I'm sure something could be cobbled together that wouldd work on the Jet. As far as turning 20 inch diameter logs between centers is concerned, the Jet is too light duty for that kind of stuff -- that's why they make the Powermatic 3520.

 

[john lucas]

I did it. I took a 12" lathe and added 4" wooden blocks to the headstock and tailstock. Then had a friend weld a longer piece onto my tool rest post. It worked great. I may have had a little more vibration but still turned quite a few larger bowls. I used MDF. Of course making it out of metal would help considerably but would probably cost a fortune. My method also probably threw some things out of alignment slightly but I never really noticed a problem. Of course I wasn't doing some of the turnings I do today that might show up the missalignment.
You do have to jury rig the bolts that lock down the headstock and tailstock. That can be challenging. I don't remember the headstock being a problem but had trouble making the tailstock locking bolt longer. Don't remember how I solved that but I did have access to a metal lathe in those days so I probably either made a new one or cut it and added an extension. That was about 16 years ago of so and I can't remember what I had for dinner yesterday.

 

[Lars Stole]

I added 2 inches to my lathe by buying precision milled 2"x2" aluminum bar (2024 cold finished bar at onlinemetals.com, but there are lots of other vendors), and then carefully cutting, drilling and tapping the pieces to make risers for the headstock and tailstock. You can get larger sizes (up to 2x6" rectangular bar, but it is pricey); for 6" aluminum risers, it would probably be more cost effective to save your money and buy a bigger lathe. BTW, I have a Stubby 750 and the bed gap is 50mm. By very precisely trimming down one piece of aluminum to 50mm, I was able to make a sled for the tail stock that is aligned dead on with the headstock. I am very happy with the result and would never consider removing the riser blocks and going back to the factory setup.

SAFETY NOTE: If you go this route of cutting aluminum bar on a table saw -- especially 2"-thick bar -- be very, very careful. I used a full-size table saw with a non-ferrous-metal blade, very slow cuts with plenty of material hold downs, and a full face shield to protect against the flying bits of aluminum glitter. If you are not prepared to think seriously about the safety of this procedure, don't do it. Find a machinist to do it for you instead.

 

[Dan Mosley]

Regarding the stand - agree the stand would be a platfrom and enough in length and width to be able to move around freely without worrying about stepping off it.

Blocks - It may be to expensive to bother with and could be its better to save up more and buy the lathe that will accomadate. However, there is a guy in San Diego, Ca. that I contacted to get a price quote from that is a machine shop and has done these type of modifications to wood lathes for some time now. There is a pro turner locally that I called several days back and he gave me the contact stating he has used him several times to do similar projects. So I figure ill wait until I see the price quote and go from there. His solution may be a attachment at the end of the lathe as suggested but im leaving it up to him to see what he thinks. He told me he will look at the specs of the 1642 and give his recommendation - nothing to lose to see what he comes up with.

I will post what he tells me along with price as soon as he emails me back ....................

 

[Don Bunce]

Each inch you block up the headstock will add 2 inches to the capacity, so it you want 20", a 2" block will do.

 

[Bill Boehme]

Each inch you block up the headstock will add 2 inches to the capacity, so it you want 20", a 2" block will do.

At least one person did the math.

A six inch increase in height would be a 28 inch swing -- a little too ambitious maybe. a two inch riser is doable although not cheap and would be far less expensive.

Rather than thinking in terms of one solid machined block, it would be more practical and less expensive to make an assembly out of smaller pieces that could be screwed together.

 

[john lucas]

After I got my lathe/mill combo machine I thought about making riser blocks by welding 4 pieces of stock together and then milling the top and bottom surfaces. I sold that particular wood lathe about that time and got a lathe with 20" swing so I won't have to do that anymore. However I am going to move my bed extension down on my Powermatic 3520A by drilling some holes in the legs. I picked up a thick piece of steel tubing to make the riser block for my tool rest the other day. Don't know when I'll have time to actually do all of that but it's in my plans and I have the material now.

 

[hockenbery]

After I got my lathe/mill combo machine I thought about making riser blocks by welding 4 pieces of stock together and then milling the top and bottom surfaces. I sold that particular wood lathe about that time and got a lathe with 20" swing so I won't have to do that anymore. However I am going to move my bed extension down on my Powermatic 3520A by drilling some holes in the legs. I picked up a thick piece of steel tubing to make the riser block for my tool rest the other day. Don't know when I'll have time to actually do all of that but it's in my plans and I have the material now.

. Thought you were retired and had all the time.... -

My to do list seems to get a lot longer than the done list.