Can You Get Perfect Horizontal Alignment By Squaring the Headrest?

dusty · Post by **dusty** » Tue Aug 21, 2012 12:33 pm

[quote="JPG40504"]If both wedge locks are not applying equal force(positioning) against the way tubes, the headstock 'may' be 'offset'. The wedges would have to have unequal wear for that to occur.(only one 'wedge' actually clamping[wedging]).

That said, non-straight way tubes are a more likely culprit.

FWIW we be looking at this multi-tasking/purpose machine as if it were a machine shop tool.

It will never be any where near as accurate nor as consistent.

That should not however be a deterrent to getting it as good as possible.]

What would happen if the wedge locks were not positioned equal distant from the tubes when first assembled? Would one wedge lock contact a tube before the other and begin twisting the assembly?

dusty · Post by **dusty** » Tue Aug 21, 2012 6:40 pm

algale wrote:I am happy to do this but need to figure out a way to get precise, repeatable measurements (a process which is not as simple as throwing a ruler against the tubes). Let me cogitate on this ...

My tools for doing this are 1) a piece of 1/8" hardboard, 2) a piece of 2" aluminum angle, 3) a 6" ruler and 4) a spring clamp.

I clamp the aluminum angle to the bottom side of the way tubes.

I stand the hardboard upright on the top edge of the bench tubes.

I scribe a line on the hardboard at the bottom edge of the aluminum angle.

I measure the distance of the line from the bottom edge of the hardboard. Adding 2" to that measurement gives me the distance between tubes.

Prior to doing all of this I mark two lines on the bottom edge of the hardboard that are 8 1/2" apart. These identify the center line of the bench tubes. I also have the center line of the way tubes marked on the other edge of the hardboard. I take the measurements at the center line of the way tubes on a line perpendicular to the edge of the hardboard..

[ATTACH]18238[/ATTACH]

[ATTACH]18239[/ATTACH]

backhertz · Post by **backhertz** » Tue Aug 21, 2012 8:12 pm

The first time I visited forum member Bill Mayo some years ago, I vaguely remember him telling me about something he did to the wedge locks, but I can not for the life of me recall what it was but as I recall, he refaced them or something. When he worked on someones's headstock, they got back a headstock with better new bearings and a straight spindle as he was finding many spindles exceeded what he established as an acceptable runout. He also was converting Gilmer quills from single to double bearing and other things being he was a machinist first, woodworker second.

I'm a member of a 10ER user group as well. Recently someone brought to my attention the old 10E/ERs had to meet a .00015" accuracy spec or the item was discarded. So I've been toying with an idea of trying 10E/ER tubes in a Mark V and see what the result is. These tubes are almost 1/4" thick. I have no idea what spec the Mark V is built to. Being there are bench tubes, the bench should be more rigid than the wooden bench the 10E/ERs were mounted on.

I remember Nick Engler back in 2008 doing a Saw Dust session to better align the way and/or the bench tubes along with his comments about the effect of the way tubes.

I've got some other projects to finish before I mess around with any experiments. And like JPG mentioned, the Shopsmith is a woodworking tool. There are more precision SPTs to achieve accuracy like the joiner and the planer.

It must be some residual OCD in me that makes me strive for the best accuracy, just because. But all in all, I've never had any problems other than the usual stuff with circuit breakers that used to pop when I turned on the Shop Vac, bogging down if I tried to do more than I should of, etc. The DVR has helped me overcome a lot of that. But to be honest, I would be just as happy using my old Greenie and doing whatever I had to do to achieve the best reveal possible.

I have several 10E/ERs of which two are almost in brand new condition. If that .00015" spec is true, I might attempt to do some light machining on one of them after I verify the accuracy. But that too is down the road. I have some curtain rods to hang right now which takes priority over all of this... I must keep momma happy or she would kill me if she had any idea all I've been spending on my retirement hobby.

JPG · Post by **JPG** » Wed Aug 22, 2012 2:28 am

dusty wrote:What would happen if the wedge locks were not positioned equal distant from the tubes when first assembled? Would one wedge lock contact a tube before the other and begin twisting the assembly?

Since the wedges merely float on the screw, there is no reference to the headstock to make initial centering a factor. They do need to be relatively centered in order to obtain full adjustment range.

I do not see a twisting result possible.

My previous comment was regarding the shape of the sloping part of the wedges that might allow effective clamping on one way tube only thus potentially offsetting the headstock very slightly.

billmayo · Post by **billmayo** » Wed Aug 22, 2012 9:01 pm

I do not see the wedge locks having any effect on alignment. For many years, I have been selling Shopsmith headstocks as a replacement for the Total Shop headstock for which no replacement parts are available. The Total Shop has 1.675" way tubes vs 1.75" on the Shopsmith. I did alignments on the Total Shop with its headstock mounted and then mounted the Shopsmith headstock. I could not find any alignment problems between the 2 headstocks other than the tailstock center was just a little lower which is adjustable. I always refile the wedge profiles so each wedge has the same profile.

algale · Post by **algale** » Wed Aug 22, 2012 10:35 pm

dusty wrote:al: It appears that you have that tube alignment about as close to perfect as you can get. It will likely change some when you roll the Mark V around the shop but not enough to alter critical alignments.

I would sure appreciate it if you would measure the vertical separation between way and bench tubes at all four corners. I am curious to see if they are even close to consistent. Mine are all different and differ by as much as 3/8".

Dusty,

Sorry for the delay in responding to this request. The distance between my bench tubes and way tubes appears to vary by no more than 3/32nds. From the bottom of the way tubes to the top of the bench tubes, I get the following:

Left Infeed: 5 and 28/32nds
Left Outfeed: 5 and 26/32nds
Right Infeed: 5 and 25/32nds
Right Outfeed: 5 and 25/32nds

Incidentally, it occurs to me the leveling screw on the left outfeed side could easily effect these measurements. On my machines, that leveling screw is totally below the surface of the headrest casting and the twist is currently 0 degrees per my Beal. Since the error on the Beal is 0.1 degrees, I probably could raise the leveling screw on the left outfeed side the 2/32nds required to make the distance between the tubes on the left end equal on both in and outfeed sides and still read 0 degrees twist.

Al

dusty · Post by **dusty** » Thu Aug 23, 2012 4:58 am

Algale:

I have two setups that are very close to yours and then the one that is all over the place (my go to machine).

I think it is about due for a tear down and rebuild.

At this stage, I don't believe yours could be any better. Thanks for the numbers.

dusty · Post by **dusty** » Thu Aug 23, 2012 7:54 am

Algale, etal:

Based on readings from these four setups, I have come to the conclusion that the target dimension is 5 25/32" (5 3/4" +-). If all four locations complied with that, you would have near perfect Tie Bar, Head Rest and Base Arm Assembly.

If you evaluate dimensions from all over the Shopsmith designs, they tend to be nice round numbers. I don't believe this to be a coincidence. That said, the Shopsmith spec is probably 5 3/4".

In your case, you could be there with a few strokes of a file on the Tie Bar on the Infeed Side.

dusty · Post by **dusty** » Thu Aug 23, 2012 9:55 am

I drank my third cup of coffee this morning while sitting in the lawn chair staring at the Mark V trying to determine what might be causing these unusual (inconsistent) measurements.

I am now wondering if maybe this is a biproduct of the lift assist. This came to mind when I noticed that the lift assist is not centered between the tubes.

Just wondering. When I attack this, I'm going to disconnect the lift assist just to see. If I get everything to align then I'll remount it and observe what happens at the left side.

keakap · Post by **keakap** » Thu Aug 23, 2012 4:10 pm

algale wrote:T..."squaring the headrest." Not surprisingly, there's a limit to how much you can twist the headrest on the bench tubes and it just isn't enough. ...Al

What does the horiz align look like if you loosen the way tube lock screws on both ends and rotate each tube individually while observing the points?
(This is the procedure for getting the headstock to slide easily on the tubes. Makes a huge difference.)