[dwalsh62]

I started looking into tool change capabilities for Sherline / Taig mills and was greatly disappointed at what I found to be available and the cost of such equipment more than stunned me.

Contacting IMSsas almost gave me a heart-attack, don't get me wrong, I can understand the need for business to make a profit but charging $580.00 for one clamp and one tool holder or $420.00 for one clamp and one tool holder with a minimum quantity of 20pcs is ridiculous.

A2Z makes some nice products but the cost of their stuff makes it hard for the average home/hobby machinist to consider because the prices are so high that they often settle for less stable, less accurate but almost free solutions because there isn't really any other options.

The IMS QuickChange while a novel concept has too many issues with tool holder slippage and the ISO10 with ER11 collet based spindle suffered the same slippage at low RPM but the extremely high costs of these two options put it out of reach for most hobby machinist so I decided it was time to make something better available at a more reasonable cost and allow the user to buy only the pieces they need/want.

Slippage occurs because there is not enough seat pressure between the tool holder and spindle taper, I purchased both style of tool change spindles and started taking measurements, the QuickChange has only 40lbs (179N) and the ISO10 while a little better only had 158lbs (702N).

Further testing and calculating I found that a minimum target force of 224lbs (1000N) is required and while the ISO10 is rated for 268lbs (1200N), the available implementation is not capable of this.

I did like the ISO10 tool change spindle with internal air-cylinder because it was very compact but the internal space is what prevents the force from reaching the required strength to prevent slippage (it has to exceed the force required to overcome the seat force).

I decided that doing it internally just wasn't going to be an option unless someone figured out how to generate significantly more force in such a small space and still maintain the 7mm of gross drawbar travel without forcing me to rob a bank to buy it.

I decided that that minimum target force would be 280lbs (1250N) so I opted for the ISO15/BT15 size tool holder which is rated at a maximum of 380lbs (1700N) and if I ran it at the minimum target or just above it, slippage would not occur at the low RPM

I chose the ISO15/BT15 size tool holder with ER16 collet end for many reasons, this allows greater flexibility in tool options and by utilizing a timing belt the RPM can be increased to 5,000RPM without sacrificing performance and making the components should be simple enough for most machine shops.

If there is sufficient interest in a conversion kit I see no reason why I couldn't mass produce the parts to lower their cost.

I have a reliable source for tool holders ($59.00ea - less than PDS charges) shafts (P20 Tool Steel - HRC52) and clamps (9160 Spring Steel - hardened/tempered) would run around $250.00, a suitable air-cylinder with a 5port 2way 24VDC pneumatic valve would be around $75.00 and belleville disc springs are cheap so it doesn't have to be expensive.

You might think these prices are high but lets examine it closely, buying these parts gives you a tool change capable spindle for less than $500.00, at least 1/3rd the cost of the QuickChange and 10 times better.

If you made your own shaft and clamp then sent them out for processing, hardening cost $180.00 per lot and tempering costs $160.00 per lot and after you get them back you have to send them out for grinding so your minimum cost is now $340.00, grinding isn't cheap either and if the grinder isn't experienced with shaft grinding where TIR is critical, your shaft might have a TIR of 0.010 which is completely unacceptable for a product with a maximum acceptable TIR of 0.00080

Taking into account that you start with a piece of 1-5/8 round stock P20 Tool Steel 8in (200mm) long (cost is $29.00) and then gets turned down to size, without the equipment to do it yourself you're paying for this service and the minimum shop labor would be $80.00 plus whatever setup fees they charge and finding 9160 Spring Steel isn't as easy to find as other materials.

I'm not stopping anyone from making their own, only offering what I believe to be an affordable option to a better solution by sharing the cost of producing 25pcs.

I've attached pictures of where I am at with my prototype and I should be done within the next two weeks and will be ready to (mass) produce the final product for use so if anyone wants one they need to send me a direct e-mail and climb aboard.

[Sthibeault]

Where do you get the toolholders for $59.00?

Sent from my DROID RAZR using Tapatalk 2

[fretsman]

I've attached pictures of where I am at with my prototype and I should be done within the next two weeks and will be ready to (mass) produce the final product for use so if anyone wants one they need to send me a direct e-mail and climb aboard.

I'm always interested in a better mousetrap, but was bummed when I could not see the pics of what you have so far.

Please try to re-upload?

Thanks,
Dave

[dwalsh62]

Where do you get the toolholders for $59.00?

Sent from my DROID RAZR using Tapatalk 2

I found a company that makes tool holders to make me ISO15 with ER16 collet ends and to do it at a reasonable price, now I'm having BT15 tool holders made because they offers a guarantee that the tool holder can't slip in the shaft.

[dwalsh62]

I'm always interested in a better mousetrap, but was bummed when I could not see the pics of what you have so far.

Please try to re-upload?

Thanks,
Dave

Sorry about that, size and pixel restrictions prevented them from posting but allowed them to be uploaded, resized and now they are visible.

[dwalsh62]

Here is the ISO10 with internal air-cylinder that just doesn't cut it, apparently it is a pair of stacked ring pistons/cylinders that give it 12mm of total travel and 160lbs of force (due to a coil spring), if someone wants to take a stab at making one that will deliver 350lbs at 80psi and have a minimum travel of 10mm I would be more than happy to provide a cheap solution of producing it and would even consider paying for it if it's a decent solution.

As you can see, the tool holder is smaller and can fit completely inside the shaft, this rules out a rotary tool changer due to toolholder clearance issues but does offer some reference for someone who wants to make something similar and isn't concerned with cutting aluminum or other similarly hard materials.

The bearing surfaces are 20mm (or 19mm on some spindles), difficult to put a taper where the taper max OD is 19.050mm but OK when the taper max OD is 16mm by off-setting it just enough to allow sufficient material between the taper and bearing surfaces.

[dwalsh62]

I've had several people contact me asking what it cost, I guess they didn't read the entire post or missed it but the shaft and clamp will cost $250.00 a set if I produce 25 sets, if 50 or more sets then the cost will be less than $200.00, I wont be making and stocking them for future sales unless someone wants to enter into a contract to make regular monthly purchases for resale and I only intend on making the one production run myself (maybe 2 if demand warrants it) and I will consider selling at a very reasonable price the technical drawings and manufacturing tricks if later someone wants to take the products and produce them but this will only occur after I have made the initial production run so I can get mine at the best possible price.

I'm also making arrangements to have Hubbard CNC Inc. in California (they've been around on ebay for a long time and many know them already) carry and sell the tool holders so a stable source will be available for anyone wanting the tool holders.

They've just set up a direct online CNC store, free shipping and no more ebay, payment is by paypal so purchasing should be rather simple and painless.

[fretsman]

Not that you asked for my opinion, but I'll give it anyway as I believe I'm not the only one thinking this.

While this all sounds great (and very hopeful and affordable), I don't think too many folks are going to jump onboard until they see "real world" examples of a working model in various materials and situations.

I see you have begun a kickstarter setup for this project with a $10,000 goal that ends in 29 days. That's very ambitious and I'm very impressed and look forward to seeing the progress on this.

Dave

[bebob1]

Does the adapter thread onto the standard sherline spindle? What happens to the internal taper of the original spindle? Or is this an entirely new spindle where you essentially have to dismount and remove your original spindle and replace with yours?

one of my worries will be the runout and the precision of the new taper of the spindle attachment.

also, with that much spindle sticking out, you lose z workspace of sherline mills which is already small. Also, due to the design of the sherline and their cantilevered z axis, the higher the spindle position, the more deflection so less precision work the higher Z you go. The sherline is more optimized for low z height work for highest precision.

[dwalsh62]

Not that you asked for my opinion, but I'll give it anyway as I believe I'm not the only one thinking this.

While this all sounds great (and very hopeful and affordable), I don't think too many folks are going to jump onboard until they see "real world" examples of a working model in various materials and situations.

I see you have begun a kickstarter setup for this project with a $10,000 goal that ends in 29 days. That's very ambitious and I'm very impressed and look forward to seeing the progress on this.

Dave

Whatever it takes to get a production run to occur so I can get a couple of the shafts at the best possible price is the stage I am at.

Tim over at A2Z has expressed an interest in the kit and wants the drawings now, more than likely they will end up over there but I doubt it will be reasonably priced if/when it does and I don't really have any other options to keep continued production happening so I either get $500.00 for the drawings when I'm done or the drawings get filed away and forgotten with the other stuff no one was interested in when I was making them.

Those who wait will definitely miss out, my recent BT30 spindle with petal clamp is a good example of "you snooze, you lose", to make it cost only $950.00, $1150.00 with the complete air-cylinder (hydraulic assist) assembly, I produced and sold 27 of them at that price, sold the technical drawings to someone in Canada for $1,000.00, his price on the spindle is $2399.00USD, he switched to a ball-clamp to save a few bucks and $450.00USD for the air-cylinder assembly without the position switches and is 6 months away from having a sellable product because the changes are giving fit/functionality issues.

It was a working and tested design, lathe, mill, EDM and grinder is the equipment needed to produce it and producing the parts per drawings gave a working product, change the clamp and you have to alter many other parts and this takes time (more if you have no experience making spindle shafts).

A few people have since asked me for one and all I can do is quote a Volis or HAAS spindle (both are more than $4k and ball-clamp based) and don't include the air-cylinder.

I tried to get another spindle design from here into production but the author can't seem to make up his mind on what he wants and drawings change drastically every week so after 3 months being unable to commit to a design I've decided to move on to other projects and this one is as good as any.

I doubt kickstarter will meet the funding goal as it's based on a 50 set minimum but I should be able to gain a few more people to help me meet the 25 set minimum so I'm hopeful that the posting will be useful in the end.

Does the adapter thread onto the standard sherline spindle? What happens to the internal taper of the original spindle? Or is this an entirely new spindle where you essentially have to dismount and remove your original spindle and replace with yours?

one of my worries will be the runout and the precision of the new taper of the spindle attachment.

also, with that much spindle sticking out, you lose z workspace of sherline mills which is already small. Also, due to the design of the sherline and their cantilevered z axis, the higher the spindle position, the more deflection so less precision work the higher Z you go. The sherline is more optimized for low z height work for highest precision.

The person working with me has been making spindles for many years, if it weren't for him I wouldn't attempt to make spindles due to allowable TIR specifications.

Raising the Z-assembly 1/2 inch restores lost Z workspace if your using the 3/4-16 screw-on tool holder, 1 inch if your using the MT1 collets, leaving you with 6.25in of travel and nothing lost.

You replace the existing shaft with the tool change shaft and it doesn't get any simpler than this:

1. remove the spindle head from the mill.
2. remove the pulley from the spindle shaft.
3. loosen the spindle shaft nut and remove it.
4. push out the spindle shaft (a rubber hammer works for the stubborn).
5. save the shaft as a backup, toss it, give it away or sell it (your choice).
6. push in the new spindle shaft.
7. tighten the spindle shaft nut finger tight.
8. tighten the spindle shaft nut an additional 1/4 turn.
9. install the pulley.
10. install the spindle head onto the mill.

[dwalsh62]

Started some tests and took some measurements, results were impressive.

Allowable TIR is 0.0002in, measured is 0.00008in, more than acceptable.

Dimensional tolerances were within specifications and when we tried to measure the breaking point of the clamp we pulled the head off of two pull studs at 583lbs and is only required to sustain 280lbs so we can safely say it has sufficient strength.

Hardness was within specifications for shaft and clamp and good a thumbs up form the spindle expert.

We started a cycle test, it's gotta run for 100 continuos hours (120000 cycles) then re-measured so it'll be a few days before I have the results of the cycle test.

I'm not too impressed with the finish of the non-ground portion of the clamp body but the spindle expert says grinding and polishing is an unnecessary step because the clamp is buried inside the shaft and this area is not viewable but he did agree to make a couple more and vary the turning process in an attempt to get a better finish.

He tells me that 9160 Spring Steel is a tricky material to get a perfectly smooth finish from when turning but he'll see what he can do to get something better than what is shown in the pics in the first post so I'll stop my whining about the appearance.

Alternately he says we can go 4 thousands under and nitride coat it for a satin finish but he believes this to be way overkill for something you're never gonna see more than the finger ends when you look in the taper so maybe I should just accept it as it is and stop complaining about how it looks.

[hydropro]

The measurements are impressive. I can't wait to get mine!!:banana: This spindle is going to fit perfectly on the Mini VMC I plan on building in the near future. Thanks, for saving me the trouble of designing and making my own.

Regards, Jose

[dwalsh62]

With everyone contacting me expressing an interest to purchase a spindle shaft and clamp I think awareness of the following fact is in order, if I don't have a minimum of 25 sets, the only persons who will get one will be me and my two friends.

If I do manage to obtain a minimum of 25 sets then, only those who committed to buying now will receive them at the rock bottom price, when it is taken over (probably by A2Z), I highly doubt it will be available at such a low price.

I don't have the time or resources to make and stock these parts for future purchases without a contract guaranteeing a specific quantity purchase over a period of time and it seems in this hobby, this is not a normal practice so the opportunity to buy cheap vanishes quickly after the initial production run unless you're buying 25 sets minimum.

What is going on over at kickstarter isn't likely to produce anything, it is just a method to collect a few more individuals who might be interested in a set or two.

As for the Rotary Tool Changer, we're working on the carousel cover and aren't really gearing up to produce any more than a couple because it is doubtful making them in quantity is needed because we don't believe it will fund on kickstarter so we're not obligated to provide or offer it and aren't taking any orders for it.

[dwalsh62]

The measurements are impressive. I can't wait to get mine!!:banana: This spindle is going to fit perfectly on the Mini VMC I plan on building in the near future. Thanks, for saving me the trouble of designing and making my own.

Regards, Jose

hydropro, I have three suggestions for you if this is your intention.

1. get a sherline spindle shaft and do your initial head design work so you are ready when it is available.
2. make sure you are on the list to receive a spindle shaft by committing to purchase one.
3. don't rely on possible future purchasing intentions to obtain one, it might not be possible and you will miss out.

[Winnfield]

I want two of these, and can commit to them. Can you please tell me how to do that (deposit, etc.)? I am dense at this hour and seem to have missed how to do that, formally. Thanks!

[dwalsh62]

I want two of these, and can commit to them. Can you please tell me how to do that (deposit, etc.)? I am dense at this hour and seem to have missed how to do that, formally. Thanks!

I say in the first post and even provide a clickable link to send me a direct e-mail.

[dwalsh62]

19 sets sold, 6 more (4 if winnfield jumps in) and I'm kicking these puppies out.

[dwalsh62]

I am dense at this hour and seem to have missed how to do that

Based on your posts I do not believe it is restricted to "at this hour" and suggest you step back, this is obviously something way beyond your skill level.

[Sthibeault]

I have a reliable source for tool holders ($59.00ea - less than PDS charges) shafts (P20 Tool Steel - HRC52) and clamps (9160 Spring Steel - hardened/tempered) would run around $250.00, a suitable air-cylinder with a 5port 2way 24VDC pneumatic valve would be around $75.00 and belleville disc springs are cheap so it doesn't have to be expensive.

e-mail and climb aboard.

Can this source you mentioned make the ISO 10 holders? I have a machine that uses these and I can not find a reasonable source for them.

Sent from my DROID RAZR using Tapatalk 2

[dwalsh62]

Can this source you mentioned make the ISO 10 holders? I have a machine that uses these and I can not find a reasonable source for them.

Sent from my DROID RAZR using Tapatalk 2

You can't find any source for your ISO10 tool holders?

Contact me by direct e-mail and I'll see what I can do.