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Hi I am planning on making an extension gap-bed for a wood lathe and would like some help in understanding in warpage expectations and how I could possibly minimize the effects.structural section is 8' @ 6"x6"x3/8"bracing is 3/8" plategap weighs 1/2"My plan as is now is to cut bevel grind all pieces and tack in position and than jump around the piece and do like 1" weld sections to not over heat one section. I am still concerned that I may be missing something on warpage? What would you all suggest for a garage builder.Thank You all again. Attached ImagesLast edited by nikodell; 01-16-2010 at 12:38 PM.
Reply:What kind of material is the lathe bed made from?Most are cast iron.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:I think you'll end up doing some after weld machining to the part to get it to flat and true. I would be planning on this machining in the planning stage and make sure you have ample material to remove.
Reply:mild steel
Reply:Originally Posted by Fat BastardI think you'll end up doing some after weld machining to the part to get it to flat and true. I would be planning on this machining in the planning stage and make sure you have ample material to remove.
Reply:Took awhile to figure out what you are trying to accomplish..But I think I got it now..Your own suggestion as to welding is the way to go BUT...It will bend and warp here and there anyway..Do you have a machine shop nearby that could possibly mill/grind it flat after it's done?8 feet is a long piece and it will be HEAVY.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:are your support pieces all identical?  I would assemble the top and support pieces first to ensure that side is all identical and the surface stays flat. Then fit the assembly to your square tube. Welding in sections is the way to go here. Try to use a somewhat thick material for your square tube. If the plate does not have to be welded all the way around, then dont do it. What weld machine and process are you using? Attached Images
Reply:Since this is for a wood lathe, as opposed to a metal lathe, I wounder if it not being 100% flat and true will make all that much difference.I went to school with a guy who's hobby was wood turning and only did a bit one time just to get a feel for it. If I remember correctly, unlike a metal lathe where the ways (sp?) set the slide, on a wood lathe the rest doesn't have as much critical effect on whats being turned. You move the chisel up down back and forth on the rest. I'm thinking about small variations, less than 1/4", maybe over 2 or 3 feet or more. Since the rest can be moved in/out, up and down to take into account differing project, can you just take up issues with the rest?I think you are right to try and keep warpage to a minimum, to move around and try to keep the heat down, and what you are thinking will probably work. One other thing would be to use a stiff back to help keep the flats flat. Often a large piece of straight I beam is used to help prevent warping. 8' of beam for a single project may be cost prohibitive, Possibly a wood beam with provisions for bolting the 2 flat plates to it might work.I'm sort of thinking flip the design 180 deg so the flats are down. Put the 2 flat strips down on the I beam and tack them only on the outer edges to hold them in place and lock the center gap. 1/2" welds every 6" or so. Then start building the rest on top of this, positioning the tube at each end and working in different areas filling in the spacers. When done take a slitting wheel and cut the tacks, and grind them down.Edit: looking back at the drawing again after the post I thought of something else. If you can, you would probably be best if you got someone with a CNC plasma to cut all the gusset plates. That way all are as close to exactly the same as possible. If you want to keep it flat, variations in tolerances in  those gusset plates will play havoc with you other wise.Last edited by DSW; 01-16-2010 at 01:20 PM..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Why there is so much welding?It is not supported at all? This is a cantilever?What kind of loads you are designing for? Do you have better picture of how this is going to be installed on the lathe?Do you have any FEA software? – That’s would be the best way to see. But with so much welding and warp – even FEA will not help.Just do not try to make it as strong as possible – look at bigger picture. If you want to provide some more information – we may be able to provide you with better service…
Reply:Nomand, what he's trying to do I believe is extend the lathe. Some units come with sections that can be added or removed to do longer projects, sort of like leaves in a dinning room table.If you look at this pict. the long horizontal beam is what he is building, either to replace the one shown, or to extend an existing one.I'm guessing he plans to turn columns with an 8' length. Attached Images.No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:WHughes: good point on the welding, I think its probably overkill welding all the way around. Material is 3/8" on the tube. Millermatic 211 and was planning on using a flux core. DSW:  I could make the thing in 2 sections that bolt together, it would make it more manageable and I could oppose the 2 flats against each other to keep them true.For wood you are not concerned with .001 although I have worked with guys that were and it just wasted a lot of time visual pieces have to fit perfect but the plastic nature of wood gives you some leeway.Last edited by nikodell; 01-16-2010 at 01:42 PM.
Reply:Nomand:I was planning on bolting on the legs/base.
Reply:DSW - thank you for the picture. That is exactly we were looking for.To Nikodell - looking at DSW's picture - imagine if you put next to it the same lathe without head and tail, or may be 2 lathes next to first one - will it be what are looking for? All bolted together making long row say 12'...Is it the goal?Last edited by Nomand; 01-16-2010 at 02:02 PM.
Reply:I'm wondering if 2 lengths of C channel with a plate welded to the bottom like this [_] might work. posibly with spacer blocks in the middle that could be plug welded or secured with bolts..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Originally Posted by DSWI'm wondering if 2 lengths of C channel like this [_] might work. posibly with spacer blocks in the middle that could be plug welded or secured with bolts.
Reply:Nomand:Roughly but the welded unit in the end is much more rigid and stable. The cast units that are big enough to be stable cost well over $3000. I am actually putting the power head together also but with much better bearings and thicker spindle than you would get in a manufactured lathe. Others have done what i am doing I just have not worked in this scale and am uncertain of the effects of welding across the 2 sides like this. Also what is not in the posted model is the end caps to allow for the sections to be filled with sand for vibration dampening.
Reply:DSW: the C sections will allow twist and result in vibration, 2 I beams twist, 2 sq sections twist, 2 tubes twist, I am moving on a known good solution just am not experienced with the welding and what to expect in warpage in this scale.Also the trapped areas will tend to pack with wood waste.Vibration becomes a major issue in wood turning while in the roughing process as wood can be extremely unbalanced during that first stage, or while turning off center.Last edited by nikodell; 01-16-2010 at 02:20 PM.
Reply:He needs the gap to hold the tool rest and the tailstock. My friend did something like you are suggesting to extend his lathe. The problem was he could only use the rest on the 1st 4' of the lathe. To do a column, he chucked the blank and turned the top. Then dismounted the work, flipped the piece and remounted it to do the bottom half, blending the 2 together. He was F'd if he needed to do a length shorter than 8', but longer than 4' unless he drilled new mounting points to move the tailstock. He needed to build a different mounting plate to mount the tail stock, since the adjustment lock is a lever with a bolt and plate that grabs the bottom of the 2 flats shown in the original sketch..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Exactly as DSW  and WHughes said.Immobilize the two ways on a FLAT table or preferably on a straight, heavy H beam.  Small tacks on ways between gussets to keep ways from drawing up as welds are made.  Skip around and take your time to keep from putting too much heat into the steel.  Small, short welds are best.  Consistency with parts will also be a big help in reducing heat.  More heat equals more distortion.  Layout and tack all parts into one piece.  Rigidity will help keep movement to a minimum.  An H beam will allow you to make your welds in flat position, again helping to minimize heat input.  Minimal heat is the key to success with a project like this.  One suggestion I would make is to consider a pipe for the main frame like Oneway uses on their lathes, which are considered by many to be the best .If you pay attention to details and do some planning, you can achieve more than acceptable results."The man of great wealth owes a peculiar obligation to the State, because he derives special advantages from the mere existence of government."  Teddy RooseveltAmerican by birth, Union by choice!  Boilermakers # 60America is a Union.
Reply:Originally Posted by nikodellNomand:Roughly but the welded unit in the end is much more rigid and stable.
Reply:This may be a stupid thought but.....Could you make an adjustable tailstock to mitigate any warpage along the length of your lathe bed?  If you could do this, you could use a laser center finder (if such a thing exists) in the tailstock to align it with the center of the headstock.  This may be an utterly stupid idea.  I'm just trying to think outside the box.
Reply:Originally Posted by joedirt1966This may be a stupid thought but.....Could you make an adjustable tailstock to mitigate any warpage along the length of your lathe bed?  If you could do this, you could use a laser center finder (if such a thing exists) in the tailstock to align it with the center of the headstock.  This may be an utterly stupid idea.  I'm just trying to think outside the box.
Reply:Bob the Welder: I am curious do you think there is something to gain in using the round tubing over the square? I am aware of One-way they are the first production type lathe done in this manner, although I think they are made to order, so not necessarily considered production.Thanks for the welding info, joedirt1966: You really want to minimize any moving parts, you generally shim the tail-stock for adjustment, there can be a great deal of on the whole unit with out of balance work pieces. I have seen a 800lbs. block of concrete being walked around shop by a crazy friend of mine, and the piece of wood was not all that large.
Reply:Tool supports are generally adjustable as you need to use different working heights for different tools and processes.
Reply:Originally Posted by nikodellTool supports are generally adjustable as you need to use different working heights for different tools and processes.Your design looks very "Robust". What will you be turning, telephone poles? Attached Images
Reply:nikodell, I was taught that pipe has one of the highest strength to weight ratios and also resists torsional loads extremely well."The man of great wealth owes a peculiar obligation to the State, because he derives special advantages from the mere existence of government."  Teddy RooseveltAmerican by birth, Union by choice!  Boilermakers # 60America is a Union.
Reply:Originally Posted by nikodellDSW: the C sections will allow twist and result in vibration, 2 I beams twist, 2 sq sections twist, 2 tubes twist, I am moving on a known good solution just am not experienced with the welding and what to expect in warpage in this scale.Also the trapped areas will tend to pack with wood waste.Vibration becomes a major issue in wood turning while in the roughing process as wood can be extremely unbalanced during that first stage, or while turning off center.
Reply:3/8 tube with the 3/8 plate all cut exactly the same and a 210 millermatic (mig process) plus alternating welds should equal zero warpage.  I do like the idea to tack your straight flat pieces to an 'I' beam or something heavy. Definitely build it upside down, and start by tacking flat pieces to I beam, then perfectly cut plates to flat pieces. Finish up that welding and while its still inverted, lay the square tube and tack it up. Flip it over, then finish the welding.It was mentioned to use some C channel welded or bolted to I beam and cutting down on a ton of welding, but if that cant be done, and you have to absolutely build thing then you should have plenty to go on. Take lots of pics of the build and post them here please.Great pics in the post above!Last edited by WHughes; 01-16-2010 at 04:04 PM.
Reply:joedirt1966: Is that a 12" structural tube it's a bit more massive than my plans and i bet that will do a tele pole. I plan on doing bed posts, and if I had more space adding to it later to do columns "this will do them in sections" which would be hallow coopered. I also want to get back into doing some turning of large vessels, not a big money maker but a good challenge.  Bob the Welder: You got me rethinking my use of materials, bracing the weighs looks to use a lot less materials. I will have to do a sketch up in autocad later. Dam You!  WHughes: Its tough to remember that camera when things get moving but I will do my best. I do have a cheap digital for the shop now.
Reply:Most bed posts I've seen are done in sections to allow the shorter lathe to be used. A long post will will also require low speed and a steady rest to support the project to keep it from throwing itself out of the lathe and minimize deflection. Norm Abrams of "New Yankee Workshop"  made bed posts in sections on one of his shows, he used a mortice and tenant joint to connect the two sections after they were turned. He used a forstner bit to drill the mortice and turned the tenant while the upper part of the post was in the lathe. I do woodwork as well and will follow this thread. Good luckHere is a home made steady rest http://www.google.com/imgres?imgurl=...ed=0CCQQ9QEwBQJodyLast edited by MrRodeoCC; 01-16-2010 at 07:09 PM.
Reply:MrRodeoCC : Many ways to skin a cat!General posting: Looking at my local steel supplier only 8" round they have in prime seconds is 1" thick 700+ lbs somewhere around 15', I am going to have to see what is available on Monday before I make my final decision than.
Reply:Quick remodel with round 8"x3/8" tube. Attached Images
Reply:As stated by others, secure the piece good, jump around with your welds, take your time so you don't put too much heat in the piece as a whole, make sure there's no gaps in your fit up, and don't put any more weld on than you need. Don't know what process you were planing on using, but my personal recomendation would be tig. Using a tube (square, round, whatever) thicker than your verticle supports should help reduce warpage too. And even if you do warp some, I would imagine you could straiten it out somewhat by applying heat to the appropriate spot along the tube. At least any up/down left/right warp. Twisting, I don't know.
Reply:You have a good design there. You will have to really work at it to get that to warp with a Millermatic 210.
Reply:Here is the heart of the beast, 2hp 3~ inverter duty motor with 3hp FUJI Frenic inverter, at 50 rpm you cannot stop or slow the drive pulley "setup for constant torque", but to operate at that rpm a secondary fan would be needed to cool the motor. Attached Images
Reply:I suggest no more than 6 lineal inches of fillet weld on each gusset.  similarly only short tacks for the flat bar.  Jump around  with your welds as you indicated.  You are after rigidity rather than strength. the 6 by 6 3/8 tube is an excellent choice.  If it does move you can easily shrink the tube since you set it as a vertical diamond in section.Heat in spots on the bottom corner, left or right corner will warp it back.   The key thing here is that it is a WOOD lathe.   As long as the tool rest and tailstock slide along everything is sweet.  Your frame could have a  1/2 inch bow over the 8 feet and the wood. spindle would not know it.
Reply:Originally Posted by nikodellHi I am planning on making an extension gap-bed for a wood lathe and would like some help in understanding in warpage expectations and how I could possibly minimize the effects.............Thank You all again.
Reply:Originally Posted by lotechman As long as the tool rest and tailstock slide along everything is sweet.  Your frame could have a  1/2 inch bow over the 8 feet and the wood. spindle would not know it.
Reply:Originally Posted by joedirt1966No offense but, I hope you get lathed soon.   I couldn't resist!
Reply:lath  (lth)n. pl. laths (lz, lths)1.a. A thin strip of wood or metal, usually nailed in rows to framing supports as a substructure for plaster, shingles, slates, or tiles.b. A building material, such as a sheet of metal mesh, used for similar purposes.2.a. A quantity of laths; lathing.b. Work made with or from lath.tr.v. lathed, lath·ing, lathsTo build, cover, or line with laths.
Reply:Any misalignment on a wood lathe is inconsequential.   The tailstock end is held on a center and it allows for all  kinds of misalignments.  The headstock spur again allows for an out of square end.        In reality you could have the headstock bolted to the concrete floor and then choose a location to lag your tailstock down on a concrete floor and you could proceed to turn your work piece.   The straightness of the bed is only important if you are going to run a carriage along it like you would with a metal lathe.   As an example: The traditional procedure for turning tapers on a metal lathe relies on a mis-alignment between headstock, tailstock and bed.  The workpice does not vibrate and object to such a setup.   This discussion is really going off base.  It is like machining the ends of all four table legs to a high precision then setting the table on a dirt floor.And really GO with your square tube set as a diamond section.  It will be the easiest to straighten if you need to flame shrink. Originally Posted by joedirt1966I think this depends on where the maximum bow is.  If i've done my math correctly (somebody ought to check my math), a 1/2 inch bow at the end of a 7 feet length will represent an angular malalignement of .38 degrees between headstock and tailstock.  PS.  I like the CAD drawings.  Much nicer than my pencil and paper CAD (crude "artistic" drawing).No offense but, I hope you get lathed soon.   I couldn't resist!
Reply:Originally Posted by lotechman   In reality you could have the headstock bolted to the concrete floor and then choose a location to lag your tailstock down on a concrete floor and you could proceed to turn your work piece.......And really GO with your square tube set as a diamond section.  It will be the easiest to straighten if you need to flame shrink.
Reply:Originally Posted by nikodelllath  (lth)n. pl. laths (lz, lths)1.a. A thin strip of wood or metal, usually nailed in rows to framing supports as a substructure for plaster, shingles, slates, or tiles.b. A building material, such as a sheet of metal mesh, used for similar purposes.2.a. A quantity of laths; lathing.b. Work made with or from lath.tr.v. lathed, lath·ing, lathsTo build, cover, or line with laths.
Reply:Originally Posted by NomandDon't you think there is something does not sit right?....
Reply:Originally Posted by NomandParticullary liked idea with concrete floor...And then flame shrink... First you take pefectly straight piece of steel - much better than you do it in your shop.After that you spend considerable time and money to warp it. And finally you flame it to unwarp...Don't you think there is something does not sit right?....
Reply:I may be foolish but I am sure its doable either way. If I was not foolish I would buy one of the China cast American brands like most others. Half the fun is getting there to me anyhow.
Reply:Originally Posted by Broccoli1he just means he hopes ya get it working soon-   http://weldingweb.com/vbb/showthread.php?t=34703
Reply:DSW made good points about using a stiff back to restrain it, tack it all together and tack and or clamp to a thick rigid piece. This will also act as a heat sink. If you have acces to and infared non contact thermometer you can monitor the heat. Try to keep it around 400 Degrees max. Lightly preheat to 300 or so.  You may also want to try to set it up with a water stream running down that main square tube to keep it cool while you are welding it up. Skip around like you said and don't rush it. Those Thermometers can be had $20 and up."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Nikodell when you set this up consider making yourself an extra long tool rest.  I have seen them about three feet long with two supports from the bed The long rest bar had two shafts running into two supports positioned on the ways of the lathe.  My example of the concrete floor was simply to point out that the straightness of your bed is not important.  In fact I have seen VERY large machine tools that simply have a headstock set in a foundation and the so called tailstock lifted and relocated with the overhead crane to accommodate the length.  I have mentioned it several times but please limit your welds and you will not have distortion problems,