Page 1 of 4
Double tilt
Posted: Mon Mar 21, 2011 4:20 am
by JPG
Took time today to do some 'experimenting'. Since the introduction of the Mark 7 discussion has taken place re retrofitting a Mark 5/V so as to allow tilting both ways.
I assembled two hinged end castings and 4 tubes. The bench tubes were installed as usual(end butted up against the 'stop'). The way tubes were then installed and the result was that the way tubes fell short of the stops by about 5/8"
[ATTACH]12347[/ATTACH]
I split the difference at both ends(5/16 short of their stops).
By pulling the hinge pin at either end, It can be tilted at the other.
[ATTACH]12348[/ATTACH][ATTACH]12349[/ATTACH]
Kinda difficult pushing the hinge pins - so - proposed alteration.
[ATTACH]12350[/ATTACH]
After drilling and tapping hole in end of hinge pin and forming the cotterpin so as to make it captive
[ATTACH]12351[/ATTACH]
This works even though I did not 'adjust the tubes' for perfect alignment.
A little bit of wiggling the way tubes as installing the hinge pin is required, but if the casting had stops to rest on that would not be required.
Posted: Mon Mar 21, 2011 8:54 am
by robinson46176
That is pretty much how I had worked it out in my head except I thought of using a pair of tractor hitch pins with a bigger handle and a hair pin outboard of the housings so that you wouldn't have to line up any holes.
I found the process quite interesting but I probably will not be doing one since I have an original Mark VII. I am not sure just how useful it would be on a Mark V (or even on the new Mark 7) since the headstock will have to always be so high even sat as low as possible. On the old Mark VII the headstock could be lowered down to within maybe a foot of the floor at its lowest setting (left end of headstock).
I would think that using a shaper attachment up from the bottom on the new Mark 7 would almost require a step ladder.
.
Posted: Mon Mar 21, 2011 11:01 am
by ddvann79
robinson46176 wrote:That is pretty much how I had worked it out in my head except I thought of using a pair of tractor hitch pins with a bigger handle and a hair pin outboard of the housings so that you wouldn't have to line up any holes....
My sentiments exactly. IMHO, the tolerances for the stock hinge pin are far to tight to make this change over an easy operation. Maybe expanding the base holes by 1/64th or so would be in order if you decided to keep that method.
robinson46176 wrote:
I would think that using a shaper attachment up from the bottom on the new Mark 7 would almost require a step ladder.
.
Nah. You just need a taller stool!
Great work, JPG! Have you considered chopping the legs to help alleviate the height problem? It could be a "stubby" Shopsmith. Hey, if you did that to a shorty, it would be a stubby shorty. Ha! Of course, I'm just kidding.
Posted: Mon Mar 21, 2011 11:09 am
by damagi
JPG40504 wrote:Took time today to do some 'experimenting'. Since the introduction of the Mark 7 discussion has taken place re retrofitting a Mark 5/V so as to allow tilting both ways.
I assembled two hinged end castings and 4 tubes. The bench tubes were installed as usual(end butted up against the 'stop'). The way tubes were then installed and the result was that the way tubes fell short of the stops by about 5/8"
[ATTACH]12347[/ATTACH]
I split the difference at both ends(5/16 short of their stops).
By pulling the hinge pin at either end, It can be tilted at the other.
[ATTACH]12348[/ATTACH][ATTACH]12349[/ATTACH]
Kinda difficult pushing the hinge pins - so - proposed alteration.
[ATTACH]12350[/ATTACH]
After drilling and tapping hole in end of hinge pin and forming the cotterpin so as to make it captive
[ATTACH]12351[/ATTACH]
This works even though I did not 'adjust the tubes' for perfect alignment.
A little bit of wiggling the way tubes as installing the hinge pin is required, but if the casting had stops to rest on that would not be required.
I think you are close. One thing to consider would be to see if there was some sort of replacement for the hinge pin that was the correct diameter but longer. That is what shopsmith did...adding the pins on the outside of the castings. Granted, they were using spring pins because the hinge pin didn't get removed, but the concept is the same.
Posted: Mon Mar 21, 2011 11:10 am
by JPG
ddvann79 wrote:My sentiments exactly. IMHO, the tolerances for the stock hinge pin are far to tight to make this change over an easy operation. Maybe expanding the base holes by 1/64th or so would be in order if you decided to keep that method.
Nah. You just need a taller stool!
Great work, JPG! Have you considered chopping the legs to help alleviate the height problem? It could be a "stubby" Shopsmith. Hey, if you did that to a shorty, it would be a stubby shorty. Ha! Of course, I'm just kidding.
Actually the pins slip in/out fairly easily once aligned. Added weight of headstock and carriage would make 'stops' to provide automatic alignment a necessity.
Well neither of you 'noticed' the simultaneous excess height solution - NO LEGS!:D
Posted: Mon Mar 21, 2011 11:17 am
by SDSSmith
damagi wrote:I think you are close. One thing to consider would be to see if there was some sort of replacement for the hinge pin that was the correct diameter but longer. That is what shopsmith did...adding the pins on the outside of the castings. Granted, they were using spring pins because the hinge pin didn't get removed, but the concept is the same.
I thought the following shows what Shopsmith did:[ATTACH]12353[/ATTACH]
I have been tempted to modify a couple of arms but just have not gotten around to it.
Posted: Mon Mar 21, 2011 1:31 pm
by JPG
SDSSmith wrote:I thought the following shows what Shopsmith did:[ATTACH]12353[/ATTACH]I have been tempted to modify a couple of arms but just have not gotten around to it.
Indeed it does! Did I miss a previous post that contained it?????
Posted: Mon Mar 21, 2011 1:49 pm
by SDSSmith
JPG40504 wrote:Indeed it does!
Did I miss a previous post that contained it?????
Though I find it hard to believe, it appears you missed one.]
Posted: Mon Mar 21, 2011 3:50 pm
by JPG
SDSSmith wrote:Though I find it hard to believe, it appears you missed one.]
Foul!!!! No fair!!!! That was the week I spent in ICU sitting with SHMBO!(edit - replace H with W)
What other earth shaking event(s) have I missed?????;)
Thanks Damagi!!!!!
I am guessing since the retaining 'screw' binds the pin. they wanted it to rotate in the outer holes, thus requiring removing the pin which keeps the pin from rotating. It used to be the inner casting rotated on the pin. Tis a better design both for assembly and repair!
Now who do I know that has a milling machine?;)
Posted: Mon Mar 21, 2011 4:04 pm
by ddvann79
[quote="JPG40504"]Now who do I know that has a milling machine?]
Milling machine? How about a hack saw and a tap and die set?
