Need blanchard grinding Southern California

[andrew whicker]

I think the problem is that the machine shop won't know what the reference is. In other words, the tables could be both high on the cutter side, but low on the other side and each side could still be flat. Does that make sense? If one or both tables were 'leaned' the wrong way, but flat, then you may not be able to adjust enough to make them co planar.

I'm not sure how you would grind them to be co-planar unless you kept the jointer together when grinding unless you want to go down a complicated path. I would grind one face flat and use it as a reference to grind the other face. You don't care about how level it is to the ground, but both faces should be level to each other. Also, if you are sending it in as one piece, you'll need to make sure that each side is very tight. After all, if one side moves during grinding, all your work is pointless. You'd need the tables to be parallel to the cutter length too unless you have some adjustment from the side nearest the user to the side opposite. If you could also send the jointer to the machine shop with the adjustments in the middle, that would be best.

Anyway, a gentleman above had good luck with an auto machine shop. I wonder if he took his apart or sent as one unit. Good luck and cheers!

Edit:
I would use the cutter body as a reference for parallelism along the Y dimension (along the length of the cutter body). Your beds need to be parallel to the cutter body. The blades can be adjusted, so I wouldn't use those.

[Peter Christensen]

I was a quality inspector and the machinists I worked with would have place the assembled jointer tables down and shim, ensuring the cutter block is parallel to the machine table, clamping it to prevent movement. Then skim the base to ensure it is flat. Flattening the base is optional but it ensures the base won't rock when the tops are machined. The machinist would then turn it over and clamp the base ensuring the cutter and tops are parallel to the machine table and clamp it down. The ends and possibly the midpoints would have jacking screws on appropreately sized blocks placed and clamped. The jacks are to ensure there is no deflection. Then the entire jointer will be machined/ground just enough until flat with flood coolant to prevent heat distortion. The fence, base and extras are removed before the work and the tables ways tightened to prevent movement. You are going to have to explain what is important in the setup and the goal when it is done unless the guy is a woodworker too and already knows. When done the tables will be as flat as the machine doing the work is capable. All you need do after is deburr the edges, clean off the coolant, assemble, wax and enjoy.

[Bill Dufour]

What I meant is a jointer table bottom is not flat or parallel to the top. This means the machinist has to figure out how to mount it so the top surface is exactly parallel to the grinders table before they can grind it. Of course they will first have to figure out exactly what angle is off so they can mount it not parallel but that slight off angle correction. Probably have to use a giant sine bar, surface plate and other expensive meteorology gear to measure the issue.
Difficult to describe since they have to measure it in three dimensions And then accurately mount it so the off bits get ground away.
Grinding too much off can cause stress which will warp the casting after it is unclamped from the grinder. Or there may be no bad stress and the casting will stay stable. I have heard of precision machined casting twisting as stress redistributes days later. sometimes the casting can be bent back into shape and it will clip and snap back into shape., Do it too hard and it may click and snap in two.
What you really need to do is check each table separately with a precision strightedge (+_$100) and see how flat they are. If they are flat, grinding is a waste of time and money. Only if they are not flat will grinding do any good.
A precision straight edge will not have numbers on it like a ruler. It is just a nice straight piece of bare steel with at least one edge scrapped to be a straight line. To be honest for wood we do not need the precision a machine tool needs. A .001 inch off is no big deal with wood.
Bill

http://www.starrett.com/metrology/me...&sortBy=wp/asc
Bill D.

[Peter Christensen]

Bill my comments in post #17 were with the assembled jointer being machined, only without the sheet metal base and fence. That's why I suggested a place that can machine truck engine heads in post #6. Machining the tables separately would increase the cost, complexity of jigging, and still not likely to end up with them coplanar.

The Mark hasn't mentioned how much or which way the tables are out. They could be banana shaped and need the surfacing to correct or there could be a .005 drop at the end and he is chasing butterflies. If the individual tables are flat then it might be easier to scrape the ways a little to bring the table ends up or down to make it coplanar.

[michael langman]

If the jointer is dovetailed to the base then the tops were ground on a fixture mounted to the chuck on the grinder.
The ways were ground first and then the tops in relation to the ways.

[Andrew Hughes]

Mark you might try taking the tables off and cleaning the Dts ways then reassemble. There's could be some pitch and dust that's hard and packed in the ways throwing things off.
Like others mentioned you need to have a precision straight. I have three my longest is from suburban tools it's six feet long.And is properly hanging from the end and stored in a card board tube. It's not a little thing setting up a jointer with a fine tune. I learned the hard way.
Good luck

[Mark Gibney]

Andrew, I checked out Suburban straightedges. That 72" one must be nice. Who knows, I might find one tomorrow at the old tool swap meet.

I stripped this whole machine down when I got it and cleaned everything - I wish the issue was perhaps crud packed in the ways, but they are clean now. Hope to take it to a grinder next week. I'll post back here on how it turns out.

[Pat Pollin]

Surface grinding will smooth a surface, remove bow or cupping
If your bed has planar issues of tilt in any direction, the regrind fixturing job has to account for that correction otherwise they will only be leveling or smoothing the surface on the existing non-parallel plane

[larry senen]

i'm sure i'll get flamed for this,,, but jointer tables don't have to be"co-planar" just set the knives off the out feed table, and start your wood a few inches and then keep pressure on the out feed table. there is more technique to the jointer than just running the wood over the tables.

p.s. i'm in so cal. p.m. me i'll give you a demo

[Bill Space]

jointer tables don't have to be"co-planar"

Interesting and possibly an opportunity for a new thread?

Angular difference between tables may not be a big deal in the real world, I don't know. I do think excessive angular difference would be an issue.

I think most of us DO keep pressure on the wood on the exit side of the cutter head during normal operation...

Seems like being co-planer make sense. Have to re-access how I use my jointer! Maybe... on second thought, maybe not...

[Keith Weber]

i'm sure i'll get flamed for this,,, but jointer tables don't have to be"co-planar" just set the knives off the out feed table, and start your wood a few inches and then keep pressure on the out feed table.

Sorry Larry, flame thrower on... I'm not buying this. Consider infeed and outfeed tables in a "V" shape relative to one another with the rear edge of the infeed table an inch higher than it would be if co-planar. Now joint a straight, 8/4, 6-foot board on it. Initially the cutter will take a big bite out of it. As the board progresses, the cut will taper off until it's not cutting anymore -- until, eventually, the cutter just kisses the board again at the end of the cut. There's no way you're ever getting a flat board in that scenario.

The opposite scenario, where the rear edge of the infeed table is dropped an inch lower than it should be. At the beginning of the cut, the front of the board will want to rise off the outfeed table. But, you try to push it down using the pressure that you described. Maybe it would work for a short piece of light lumber, but you're not pushing down the front of that board with a "few inches" of overlap on the outfeed side, when you've got almost 6 feet of board wanting to rest on the infeed side due to gravity.

Yes, 1" out of co-planar is extreme, but the same effect continues at a reduced rate as you bring it towards co-planar until you reach a coplanar situation and everything works as it should. Flame thrower off.

[Andrew Hughes]

They can be a little bit off but at some point it's just useless.

I want to apologize to Mark for not taking into account his budget. I was just thinking today woodworking is a very expensive hobby or business if you have the passion.
I certainly don't want anyone to go into debt or sell a kidney just to get a machine working.

[Bill Dufour]

I think some people have coplaner confused with parallel. Coplaner is not the way a jointer works. the infeed is a little lower then the outfeed which is even with the cutters. Note even with the cutters not the cutterhead. The two tables are parallel to each other in three? dimensions but offset vertically by the depth of cut.
Bill D

[Keith Weber]

I think some people have coplaner confused with parallel. Coplaner is not the way a jointer works. the infeed is a little lower then the outfeed which is even with the cutters. Note even with the cutters not the cutterhead. The two tables are parallel to each other in three? dimensions but offset vertically by the depth of cut.
Bill D

I don't think anybody is confusing the term. If you bring the tables to the same height, they are indeed co-planar. That's where they need to be when you want to test and adjust your setup, hence the term and why it's used when talking about jointers. It's kind of obvious that the jointer won't cut like that, and the infeed needs to be lowered before using it.

[Mark R Webster]

Mark I did my vintage 8" delta jointer at Steel Services Grinding in LA http://www.steelservicesgrinding.com. I was there when they did it and supervised to be sure it was done correctly. It was ground with the in and outfeed tables in place I tightened them down at the same plane as best I could before I arrived, and had them place supports under the ends of the tables to prevent sagging during the grinding. Pretty happy with the results. The swirls don't bother me. I can't remember how much it cost me though

P.S. Before they ground the top surfaces of the tables, they did an initial grind on the bottom of the base with the table surfaces facing down on the grinder table to create a base surface that was closer to the starting plane of the tables. Once the bottom surface was ground they flipped the jointer upright and ground the table(s) surface (tables supported at the ends)

All of that said, I don't know if I would spend the money on an older chiwanese. But guess that depends on what they want to charge you to grind. You might be better off looking at Grizzly. The prices are too bad these days and the quality is much better than 20 years ago.