Smithy Midas 1220 LTD Quick Change Toolpost Help

This forum is dedicated to those hobbyists with the 3-in-1 metalworking machines. Mill-Drill-Lathes. Tips, techniques, modification and use of these machines is topical.

Moderator: Harold_V

heavyg603
Posts: 59
Joined: Thu Feb 16, 2017 1:17 pm
Location: NH

Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by heavyg603 » Thu Mar 02, 2017 10:40 pm

Hello,
First post here so if I'm going about this the wrong way, please let me know.

I have a Smithy Midas 1220 LTD I bought last year. Been working with it enough that the toolpost is a pain so I wanted to upgrade to a quick change one. I ordered one online (http://www.ebay.com/itm/111578743893?_t ... EBIDX%3AIT) and the Chicago Bolt from Smithy to bolt it onto the exising cross slide bolt.

My problem is I think I may have ordered the wrong size QCTP. Based on some other online recommendations, and wanting to get one high enough to allow me to flip my tool over and thread in reverse away from the spindle, I got the AX size that comes with what I think is a M15 bolt. The challenge is that the bolt that comes with the existing compound is a M10 so this leaves a bit of slop in the hole. A trial run seems to indicate its solid but I'm worrying that it may slip around over time. Was thinking of cutting a bushing and trying to improve things that was.

Has anyone else done this mod and have any advice on the sizing (maybe I should of got the 0XA ?) or other fit up advice ? Thanks in advance!

Torch
Posts: 1545
Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by Torch » Fri Mar 03, 2017 5:14 am

If I understand correctly, the bolt that came with the QCTP is too large in diameter for the slot in your compound? If so, I faced the same problem when I fitted my QCTP to my machine. Although it was not an AXA nor a Smithy, perhaps you could do as I did and turn the new bolt to fit the slot instead of trying to use the undersize bolt in the toolpost? I documented my mod in pictures here:

http://www.chaski.org/homemachinist/vie ... 27&t=87470

It has been said that a lathe is the only tool that can build itself (although I think that argument can now be made for 3D printers and CNC milling machines!). I have not put that to the ultimate test, but I have certainly used mine to modify itself repeatedly. ;-)

heavyg603
Posts: 59
Joined: Thu Feb 16, 2017 1:17 pm
Location: NH

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by heavyg603 » Fri Mar 03, 2017 6:53 am

Thanks for the reply. I checked out your post, nice work, pics really helped too. Unfortunately the Smithy compound is very odd. It doesn't use a t slot at all to hold the tool holder on it uses that skinny bolt that feeds up through the compounded and is held in by its oval skinny (about .125) head that is about the same distance above its lead screw. I was toying with the idea of trying to make a similar head that would allow me to use that bolt. Just need to get my head around making that funny oval head. Not sure why smithy chose this design.

Torch
Posts: 1545
Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by Torch » Fri Mar 03, 2017 8:56 am

As I said, I don't have a Smithy, so I can only imagine without pictures.

An oval can be turned with the lathe if you have a 4-jaw chuck. You start by turning the piece to the diameter of the widest point of the oval, then offset the piece in one direction to form one side of the narrow part of the oval, then offset the same amount in the opposite direction to turn the other side of the narrow part of the oval.

But I assume that if the Smithy bolt is smaller in diameter than the AXA bolt, then the hole it must pass through is also smaller? You would have to drill out the hole -- will that leave enough meat for the oval recess? Is there enough difference in diameter to make an oval-head 8mm threaded stud and tap the inside of the AXA bolt? Or an oval-headed "T" nut that the AXA bolt could thread into? Perhaps your plan of a bushing is the best option, although the walls would less than 0.100" thick. Tricky to turn over a long length.

What about abandoning the oval-headed bolt and tapping the hole in the compound? Turn the AXA bolt into a custom stud.

heavyg603
Posts: 59
Joined: Thu Feb 16, 2017 1:17 pm
Location: NH

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by heavyg603 » Fri Mar 03, 2017 9:33 am

Sorry about my lack of pics, I'll snag a few over the weekend. Yes the hole in the top of the compound would need to be enlarged to use the bigger bolt. You might be onto something with taping the compound. I was toying with turing the end of the bolt down to fit through the hole and making a oval that would use a large flat head screw to secure on the other side but was unsure how that would hold up.

Unfortunately a 4 jaw is still on my purchase list but I think I might be ok with a just making a round piece and milling down each side. Not quite an oval but close enough to fit the hole.

heavyg603
Posts: 59
Joined: Thu Feb 16, 2017 1:17 pm
Location: NH

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by heavyg603 » Mon Mar 06, 2017 10:10 pm

Ok I decided on a one piece bushing solution. Was the simplest and was running short on time. I also came to the realization that I might be over engineering this whole thing since I used the tool post without the bushing during the creation of it lol. Nonetheless I made it out of some 316L I had hanging around. The shoulder is .24 which is just a couple thou less than the pocket, I just didn't want to fool around with reworking this if it was riding on the bushing and not the larger toolpost surface. The disk itself is 1.178. I can get the exact dimensions if someone needs to make one for themselves. Sorry about the flipped pics, not sure why they did that since they weren't that way on my PC.
IMG_1784.JPG
The challenge
IMG_1785.JPG
Turning down a piece of scrap stainless
IMG_1787.JPG
Boring the hole for the original bolt
IMG_1788.JPG
Finished piece
IMG_1789.JPG
Finished piece in place

Torch
Posts: 1545
Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by Torch » Mon Mar 06, 2017 11:13 pm

Looks good. I trust it will provide good service for many years.

toolroom
Posts: 50
Joined: Sat Jan 26, 2013 11:12 am
Location: Portland (area) Oregon

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by toolroom » Tue Mar 07, 2017 10:43 am

Smithy has a bushing specifically for that it should be in their website. It is called a "Chicago Bolt pn# 45-268. I bought and used one on my Smithy for quite awhile with no problems. Inexpensive too!

User avatar
NP317
Posts: 1925
Joined: Tue Jun 24, 2014 2:57 pm
Location: Northern Oregon

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by NP317 » Tue Mar 07, 2017 11:26 am

Nicely done. Simple solution.

I suspect your pictures are "sideways" because they were taken near the Equator...
:shock:

~RN

User avatar
warmstrong1955
Posts: 3397
Joined: Thu Mar 18, 2010 2:05 pm
Location: Northern Nevada

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by warmstrong1955 » Tue Mar 07, 2017 11:33 am

Hey....your compound looks about the same as the one on my 1340!

Your bushing looks about the same as the one I built for my 1340 as well!
Smithy didn't sell the Chicago Bolt, back when I got my Phase II QC.

:)
Bill
Today's solutions are tomorrow's problems.

heavyg603
Posts: 59
Joined: Thu Feb 16, 2017 1:17 pm
Location: NH

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by heavyg603 » Wed Mar 08, 2017 9:54 pm

I actually looked for a replacement compound but couldn't find anything to fit. Interesting they'd use the same one. I was surprised how solid the lockup is with the chicago bolt actually. When first installing it I didn't have much hope for rigidity but it seems to do a decent job. Using the bushing and the chicago bolt keeps it rigid and rotating it keeps it on center too. Now I'm just fighting with my DRO mount lol.

User avatar
warmstrong1955
Posts: 3397
Joined: Thu Mar 18, 2010 2:05 pm
Location: Northern Nevada

Re: Smithy Midas 1220 LTD Quick Change Toolpost Help

Post by warmstrong1955 » Wed Mar 08, 2017 11:03 pm

I did a DRO too!
What axis is giving you a problem?

Bill
Today's solutions are tomorrow's problems.

Post Reply