• This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn more.
[4]

Modifying Top Slide For QCTP

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#1
I have a new QCTP but it is meant for a T slotted top slide. Mine has only a single bolt. The bolt passes through a raised "collar" which is integral to the top slide. In order to use the new tool post I have to remove the collar portion. My question is how best to do so. I have a lathe and a drill press. These are the options I came up with:
1. drill it off with the drill press. Seems a bit crude but easily set up.
2. put it on a face plate on the lathe and turn it off. Or
3. Cut it off with a hacksaw and file it level. Also crude.

So how would you do this or do you have a way to leave it in place and still get the TP to fit?
Al
IMGP9280.JPG IMGP9282.JPG IMGP9286.JPG IMGP9287.JPG

IMGP9280.JPG IMGP9282.JPG IMGP9286.JPG IMGP9287.JPG
 

PurpLev

Active User
Active Member
Joined
Feb 22, 2012
Messages
888
Likes
1
#2
I'm all for modifying tooling but always weary of cutting off OEM parts. would you be able to turn a ring to sit between the compound and the QCTP? or would that raise the TP too high up?
 

Kennyd

Active User
Active Member
Joined
May 1, 2011
Messages
476
Likes
4
#3
If Sharon's idea won't work for you, I would use the faceplate method or find a buddy with a mill.
 

Giorgio

Active User
Active Member
Joined
Aug 6, 2012
Messages
35
Likes
0
#5
I'm in the same situation

so to modify the QCTP and leave the lathe tool post intact is my route...the collar is called a boss...these guys leave it in.

Here is a link with detailed instructions.
http://www.cnccookbook.com/MTLatheQCTP

video of another guy who did the same ... not as detailed

http://www.youtube.com/watch?v=JK-SjoKnjDc

here is the basic plan...Note that these are not all the correct measurements of my or probably your toolpost, but the concept seems sound

. attachment.php?attachmentid=43673&d=1355299196&thumb=1.jpg
 

Attachments

ScrapMetal

Active User
Active Member
Joined
Apr 6, 2011
Messages
2,049
Likes
112
#6
Is it possible to counterbore the toolpost?
That's probably what I would be looking at doing. I would think you would be able to bore it out on the lathe and not be in a danger of contacting the inner mechanism in the post. You should be able to see if it's "doable" when you disassemble the post to put it on the lathe.

It would also be nice to know just how the post on the compound is connected to the slide. Maybe you could still use it or maybe you'd need to make use of the one that come with the QCTP. I can't really tell from the pics how much they differ in diameter and length.

-Ron
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#8
Thanks to you all.
I will peruse the QCTP and see if it looks feasible to counterbore it. I always like to run these things by other people. When I was flying, the Aviation Safety Letter used to say, "Learn from the mistakes of others because you won't live long enough to make them all yourself". I try to hold myself to that.

Sharon, I'm of the same mind. I hate to make irreversible changes to the OEM design. I think the wider collar around the boss will make it too high.

Giorgio, thanks for the links and thoughts. The stock bolt is too short to reach up through the TP. The original and new bolts are very similar in OD so I'm not sure if the sleeve is the best option. I can probably modify the new one of make one to fit. The original bolt has a round head on it about 1/8" thik. It has a lug on one side to prevent it from turning. It shouldn't be too tough to duplicate it.

I like the idea of retaining and using the boss. It just seems to be a more rigid proposition. Again, thanks.

Al
 

PurpLev

Active User
Active Member
Joined
Feb 22, 2012
Messages
888
Likes
1
#9
in that case, I'd also opt for counterboring the tool post. will also give you extra friction support.
 

fenderfour

Swarf
Registered Member
Joined
Oct 24, 2012
Messages
2
Likes
0
#10
This was my first project on my machine.

The standard tooling was a 4-way toolpost and I wanted to use a QCTP. I took apart the crosslside and found that the stud was held in with a very slight press fit and a roll pin to prevent spinning. I removed it to take some measurements, reassembled the whole thing and used the 4-way to make a whole new stud. It took a while to machine the majority of the length down to the final diameter while leaving the large shoulder, but it was a good exercise.
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#11
I did some measuring and staring. Took the QCTP apart to have a look. The boss is just under and inch in dia. If'n I bore out the base of the TP it will cut away the threads in that area where the central shaft tightens down to clamp the wedges to hold the tool holder. So it appears to me that Sharon's idea to turn a ring to surround the boss is my best option at this point. I was in the city today and stopped in at a purveyor of small quantity / high price metals. They had nothing big enough. I have a piece of 6061 aluminum so I'll try that as proof of concept. If it starts to wear and gall I can replace it fairly quickly with something more robust- maybe even case hardened. At the rate I use this lathe it could last for years. I had the thought of overlaying it with a thin sheet of stainless or something- maybe .030".

The two bolts are within a couple thou of each other. Just under .500". So I can adapt the new one since the original is too short. Thanks you all for the input.

Al
 

ScrapMetal

Active User
Active Member
Joined
Apr 6, 2011
Messages
2,049
Likes
112
#12
Allan,

It would be great if you could take some pictures as you're doing your mods to post.

Glad you have a plan figured out,

-Ron
 

KenS

Active User
Active Member
Joined
Aug 2, 2011
Messages
144
Likes
24
#13
I have a new QCTP but it is meant for a T slotted top slide...So how would you do this or do you have a way to leave it in place and still get the TP to fit? View attachment 43736 View attachment 43737 View attachment 43738 View attachment 43739
Al,

The easiest way is to buy a second compound rest top and modify it properly to fit you AXA. Here is your stock unit:

http://www.littlemachineshop.com/products/product_view.php?ProductID=2820&category=

And here is the now discontinued modified unit:

http://www.littlemachineshop.com/products/product_view.php?ProductID=3039&category=1963256898

Notice the the the tool post of the discontinued modified unit has been cut off, and about half its deck has been milled to lower the AXA in relation to the center of the chuck. These modifications allow tools in the AXA tool holder to properly center on the work piece. To avoid milling the compound deck, Lathemaster mills the bottom of the AXA tool holders it sells to accomplish the same lowering in relation to the horizontal center axis of the lathe. But I must warn you that milling hardened steel AXA tool holders is not an easy job. It's much easier to pay a local machine shop $25 to get the deck milled if you're not equipped to do the job yourself. You don't have to mill the deck, but be forewarned that some of the larger tools an AXA is capable of holding won't lower enough to reach the center of the work piece. I would strongly suggest milling it down.

If you cut off the existing stub, you will have to drill and tap the compound to accept the 7/16-18 thread AXA center post. You can use a half-inch drill to enlarge the existing tool post hole, and then thread it. I turned an auxiliary collar from a 7/16-18 nut (using a 7/16 bolt and another nut to form a temporary arbor) to secure the bottom threaded portion of the stud. Plenty of permanent red Loctite has prevented the post from turning. I know of some who have used JB Weld epoxy to secure the AXA post. I would also be possible to drill and tap the compound for a set screw to secure the post from turning.

One of the most difficult parts of this job that no one seems to mention, is machining a new gib for the second compound rest top should you go that route. Little Machine Shop sells a gib that can be made to work-- albeit not quite perfectly-- for $5.80. I can look up the part number if you decide to go that route. That being said, I have no slop in my compound after some careful machining of the LMS gib.

Since the 7/16 threaded center post of the AXA is typically designed to drop down into a tee-slot on bigger lathes, you may find that you run out of threads when trying to tighten it to the compound. A 7/16 washer-- or turn-your-own spacer-- under the AXA top nut will solve that problem.

I had the much smaller A2Z QCTP on my lathe, but the AXA mod is definitely worth the time. It takes the lathe to a whole new level.

Here's a link to an AXA installation where the owner did not mill the deck. But it offers a good overview of what is entailed in the conversion:

http://thehobbyistmachineshop.com/cms/workshop/phase-ii-series-100-qctp
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#14
Ken, thanks for your thoughtful input.
That LMS slide does look quite similar. Mine lathe is not an 8x14 or 8x14 but an old Tida 10x36. So I asked LMS about the dimensions just on the off chance it might fit. That would be sweet, indeed. I'd rather mill the tool holders in the case where the new slide wouldn't fit. If the new slide would fit it would be easier to mill the slide deck.

You reference the bolt as 7/16" but both my old and new one are 1/2". The original has a round head with a pip on the outside edge that pushes into a recess on the underside of the slide. It does not thread in. The pip goes into a slot in the recess to stop it from turning.

This all seemed so simple when I started. Replace that fiddly old 4 way with a QC. But servants beget servants, they day. I actually cut some threads yesterday. Haven't done that in years. It was on a piece of stress proof. It cuts well enough but threading was a little rough looking. Al least I got something done. I sometimes think
that by the time I get all the tooling sorted out I'll be too old to use the machine. Thanks again.
Al
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#15
For reference, here is the QCTP without its clothes on. The base is obviously only about 1/2" thick and the wedge slots are quite close to the threaded hole so it can't be counterbored to 1" without weakening the whole block.

IMGP9292.JPG IMGP9295.JPG IMGP9300 - Copy.JPG IMGP9301.JPG


I e-mailed LMS but they weren't willing to measure it for me.
Does anyone have the general measurements from their 8x12 (14) top slide?

My top slide measurements are:
Length Over All: 7"
Width Over All: 3"
Dovetail Opening: 1.78 - 1.844
Thickness at Front: 1"
Depth of Dovetail: <.500"

It would be nice not to hack the original.


This is the top slide casting without its clothes on. You can see the original bolt has a "pip" just under the head to keep it from turning. It appears to be a pin pushed in. In the large hole in the casting you can see the slot that the "pip" fits in.

IMGP9331.JPG IMGP9332.JPG IMGP9333.JPG IMGP9334.JPG IMGP9336.JPG
Does this look the same as what your 8x12 is? 'Twould be great if it was. Except it would be one more purchase down that slippery slope. Lathes should be like printers: the lathe is free but you have to pay for the tooling.

Al

IMGP9292.JPG IMGP9295.JPG IMGP9300.JPG IMGP9301.JPG IMGP9292.JPG IMGP9295.JPG IMGP9300 - Copy.JPG IMGP9301.JPG IMGP9331.JPG IMGP9332.JPG IMGP9333.JPG IMGP9334.JPG IMGP9336.JPG
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#16
Well with Christmas and a trip to sunny climes out of the way,and getting back into work, I also got back to my tool post. I decided to take the large washer approach to go over the boss. Much time spent to accomplish so little. When you aren't set up everything takes soooo long. All those little bits of rod, bar, slices of pipe and so on are absolutely essential. I added a few of them to my collection. Now if I can just keep it all organized so it falls to hand when needed. If you can't find it you might as well not own it.

Any way, on to the QTP. I turned a slice of 3"dia leaded steel to the height of the boss. I then bored it to the dia of the boss. (well acutally it is about .005" too big but I won't tell if you don't.) I found an old container of Sulfo that I bought at a garage sale years ago. It really made nice cuts when applied with an acid brush.

One of the problems with the fat washer approach is that the tool holder may be too high because it rests on the washer and can't drop down far enough. In a rare moment of insight, I decided to cut a flat on the edge of the washer. I slathered some layout blue on the washer and assembled the top slide and QCTP. I used the edge of the TP to scribe a line across the fat washer. Then I scribed a short line at the dovetail. Once again I took it apart and scribed the dovetail line across the face using the first line to keep it parallel. Next step was to cut it off in my chinese band saw lifted to the vertical position.

I filed the cut edge with a Nicholson Magic File or whatever they call it. It does a very nice job of cutting and smoothing. After a couple of test fits it was nearly done except for breaking the edges of the freshly filed edges.

Next needed was to alter the bolt that was intended to screw into the block that fits into the t slot. My lathe has a dearth of t slots. I decided to drill and tap a piece of 3/4" 1018 round for the head of the bolt. I decided to buy a good tap and drove into the city to snag a Cleveland 14mm x 1.5. It cut like a hot knife throgh butter with a nice smooth finish. My motto is, "it's always cheaper and easier to do it right the first time". I acutally did so this time. Like Alice in Wonderland, I am guilty of giving myself very good advice but seldom ever following it. Once the rod was tapped, I parted it off to the same thickness as the collar on the original bolt and threaded it on with Loctite. Then I drilled a blind hole up against that "head" for the "pip" that prevents the bolt from rotating. The drill bit was a Canadian Tire cheapy which also got Loctited in place. After the Loctite hardened I cut it short with the handy dandy Dremel tool. The bolt was chucked in the lathe and the excess cut off and filed smooth. Now it was all assembled for what I hope is that last time so I can actually make something besides lathe parts. The results are seen in the photos.

Full disclosure: The bolt is actually a tad small in diameter since the original is slightly larger where it goes through the boss. It is also a little shorter than it should be. The bolt does not come all the way through the nut on the QCTP. Maybe some day when all other projects are done I will make a new one. As if.

Also the tool holder stud is too short to allow the tool holder to bottom on the top slide and still keeping both nuts on it. It shouldn't be too big a job to replace it with a longer one.

And most aggravatingly, the hole I bored through the fat washer is about .005" too big in diameter so that it isn't a nice snug fit over the boss. I don't think it will affect the operation, though.

I like the look of this change and it felt good not having to lop off the original boss. Not to mention the work it would have involved to do so. IMGP0016.JPG IMGP0017.JPG IMGP0018.JPG IMGP9997.JPG IMGP0001.JPG IMGP0004.JPG IMGP0003.JPG IMGP0005.JPG IMGP0006.JPG

IMGP0016.JPG IMGP0017.JPG IMGP0018.JPG IMGP9997.JPG IMGP0001.JPG IMGP0004.JPG IMGP0005.JPG IMGP0003.JPG IMGP0006.JPG
 

Allan

Active User
Active Member
Joined
Oct 7, 2012
Messages
188
Likes
10
#18
Good to hear from you, John.
From the other thread our machines look very similar. As you can see the bolt is just pressed in (not very hard). It is actually held by a friction fit in the boss. If you look closely the bolt is wider in the area that passes through the boss. I just tapped on the bolt with a brass hammer and it popped right out. The bolt is a 14mm upside of the boss and the thread is 14-1.5.

Your BXA may have room to counter bore the base. My AXA didn't. Let me know how it turns out. I've got to go out and clean my lathe.

Al
 

JohnAspinall

Active User
Active Member
Joined
Feb 20, 2012
Messages
69
Likes
1
#19
From the other thread our machines look very similar. As you can see the bolt is just pressed in (not very hard). It is actually held by a friction fit in the boss. If you look closely the bolt is wider in the area that passes through the boss. I just tapped on the bolt with a brass hammer and it popped right out.
Good to know! If you read the other thread, there was quite a bit of speculation on how the bolt is held in. Having a new data point with you saying "same manufacturer, similar looking cross slide, it's pressed in", is a big plus.

Your BXA may have room to counter bore the base. My AXA didn't. Let me know how it turns out.
I will let you know. Some measurement on the "naked" QCTP is now subtask number one.
 
[6]
[5] [7]