Explain more?
Aren't those press fit in? They usually all have an asymmetric arrangement
of the ball circuits. So with five circuits, if you have five grooves you
can still turn them around. If ten, then you can't.
Obviously I don't mean rotate on the rail axis, but swing 180deg
horizontally.
Hi Roland,
These are supported rails with open bearings that can't be rotated. That
was one of the first things I checked ;-)
Les
On 29/04/2019 16:52, Roland Jollivet wrote:
Les, have you looked at turning the bearings around? If it's easy enough,
you could press the bearings out and swing
Les, have you looked at turning the bearings around? If it's easy enough,
you could press the bearings out and swing them 180 degrees. They'll now
run on a new part of the rail.
Assuming of course, that the front and back are similarly mounted and have
both been making the same groove.
On Mon,
Those self lubricating bushings tend to have a relatively large amount
of backlash, especially after a bit of use. Ball type bushings work well
even in dusty environments as long as you keep them greased. As the
rails are very smooth rubber wipers will clear the dust very effectively.
I on not
Another way to drive both sides with one motor is screw shafts down both sides,
connected at both ends with chains or belts. Use angular contact bearings on
the ends of the screw shafts so they can be put under some tension for high
speed running without whip.
There are some open type bushings. But I don't know how the will behave.
Just curious about them.
https://www.aliexpress.com/item/OP-JDB-304564-copper-sleeve-the-same-size-of-LM30-OP-linear-Solid-inlay-graphite-Self/32310066889.html?spm=2114.search0104.8.38.28173ea0iA8XJ7=ae803_3
El dom., 28
If you use bushings over round rails how will you support the rails? A two
meter round rail will sag. Bushings work well on short rails that don't
need support. I have some on 10mm dia by 250mm long rails.
On Sat, Apr 27, 2019 at 1:57 PM Leonardo Marsaglia
wrote:
> >
> > Any rack you
>
> Now I better go take the missus her freshly made morning coffee and see
> what she wants for breakfast.
It doesn't matter the country or language, it happens to all of us haha.
El dom., 28 abr. 2019 a las 10:38, Gene Heskett ()
escribió:
> On Sunday 28 April 2019 05:52:45 andy pugh wrote:
On Sunday 28 April 2019 05:52:45 andy pugh wrote:
> On Sun, 28 Apr 2019 at 03:08, Gregg Eshelman via Emc-users
>
> wrote:
> > I just don't see the point in making the electronics and electrical
> > system more complex when there's no need for it.
>
> I think that the reason is that it can be
On Sun, 28 Apr 2019 at 03:08, Gregg Eshelman via Emc-users
wrote:
> I just don't see the point in making the electronics and electrical system
> more complex when there's no need for it.
I think that the reason is that it can be simpler to route wires to
two sides of a moving gantry / moving
With a physical connection between the two sides, the gantry cannot get out of
square, aside from a serious mechanical problem. It also frees up a motor
driver for other use or eliminates the need for one driver.
The software is also simpler because it doesn't need to be able to ensure that
the
>
> Any rack you make, even if machined perfectly will have some backlash. It
> is unavoidable.Belts have zero backlash if you use the belt the way it
> was designed -- the belt moves
I said rack because I didn't know how to call it but the idea is to make
the rack in wich the belt can
Any rack you make, even if machined perfectly will have some backlash. It
is unavoidable.Belts have zero backlash if you use the belt the way it
was designed -- the belt moves
If you want to use a belt, contact the sale engineers at
https://www.sdp-si.com/ or at least read the technical
>
> Cutting your own racks, while doable is a heck of lot of work for the
> lengths you are talking about, even if you make it in short sections. If
> your time is worth even a fraction of minimum wage you would be better
> off using off the shelf rack and pinions.
I know it sounds like a pain
>
> With any rack or rack-like drive a gantry can have zero racking problems
> by connecting the drive on both sides with a shaft.
Gregg, sounds you don't trust too much on having two motors driving the
gantry. I've seen too many machines working this way but I would like to
hear your opinion
10m, 35mm width T5 for $60
https://www.aliexpress.com/item/10Meters-T5-open-ended-timing-belt-T5-30-W-30mm-T5-timing-belt-polyurethane-with-steel/2051875939.html
That's a good price. Two of those would do both sides of a 4M machine.
That is steel cored which is stiffer than Kevlar. Pity
On Wednesday 24 April 2019 07:59:37 andy pugh wrote:
> On Wed, 24 Apr 2019 at 12:02, Les Newell
wrote:
> > One issue I see with off the shelf belts is that none of them have a
> > symmetrical profile. T section looks symmetrical but if you check
> > the drawings it isn't.
>
> T section is what
On Wed, 24 Apr 2019 at 14:36, Les Newell wrote:
> Huh, I didn't think of that. Yes, that would work. Availability of
> longer lengths at sane prices seems to be a bit of an issue though.
10m, 35mm width T5 for $60
But I think that is allowed for in the design, when you tension the
traveller loop you pull the belt on one side in contact with one set
of fixed belt faces, and the other side of the pulley to the other set
of faces.
Huh, I didn't think of that. Yes, that would work. Availability of
longer
On Wed, 24 Apr 2019 at 12:02, Les Newell wrote:
> One issue I see with off the shelf belts is that none of them have a
> symmetrical profile. T section looks symmetrical but if you check the
> drawings it isn't.
T section is what Bell-Everman use.
The Specification document for T section is
Cutting your own racks, while doable is a heck of lot of work for the
lengths you are talking about, even if you make it in short sections. If
your time is worth even a fraction of minimum wage you would be better
off using off the shelf rack and pinions.
Here is how I think I would go about
If you need height clearance for a cross shaft, mount the shaft up high and run
1:1 belts or roller chains down the ends. Or if the table is stiff enough to
only need supports at the ends you can run the shaft under the table, and have
the racks on the bottom so dust and crud can't fall into
Rack teeth are easy to machine because they have straight sides to mesh with
involute gear teeth.
Another method like using the belt is a roller chain stretched between anchor
points and looped under two idlers and over a drive sprocket between and above
or below the idlers.
With any rack or
>
> Since you're going to machine the 'rack', the type of belt is no longer an
> issue in terms of profile matching.
> But the advantage of your choice of HTD is that all you'll need is a ball
> nose cutter to machine a mating profile.
>
Well, as I told Andy, I've been reading about the round
>
> You are looking at reducers on Aliexpress, so why not use T5 belt from
> the same source? Then you have the option of using the Servobelt
> system or something else?
> Incidentally, I have the correct gear hob for T5 timing belt so can
> tooth custom sprockets if that helps.
>
On Tue, 23 Apr 2019 at 15:16, Leonardo Marsaglia
wrote:
> Well I think gluing a belt that long and wide with a proper jig or the
> right equipment could be a pain in the ass so I'm thinking about what
> Roland sugested. To machine the rack in wich the belt will be running. That
> way I can
On Tue, 23 Apr 2019 at 14:16, Leonardo Marsaglia wrote:
> The only thing that I need to decide yet is the belt profile for the
> system, since I don't need the belts to fit into each other I can make the
> racks with any profile. I'm thinking about using HTD or GT2 but that's not
> decided yet.
Well I think gluing a belt that long and wide with a proper jig or the
right equipment could be a pain in the ass so I'm thinking about what
Roland sugested. To machine the rack in wich the belt will be running. That
way I can guarantee zero strecth and perfect engagament.
I plan to make the
I quite like the servo belt idea but I think it needs pretty accurate
clearance between the fixed and moving belts. Note that you can't clamp
the fixed belt. Clamps cover the teeth. If I was doing this I'd look
into polyurethane based adhesives. For instance the stuff they use to
bond in car
On Sunday 21 April 2019 16:21:36 Andy Pugh wrote:
> > On 21 Apr 2019, at 18:49, Leonardo Marsaglia
> > wrote:
> >
> > Do you guys think that it's mandatory to glue down the belt to the
> > surface? Or having it well streched is a possibility?
>
> It’s the bonding down of the counter belt that
> On 21 Apr 2019, at 18:49, Leonardo Marsaglia wrote:
>
> Do you guys think that it's mandatory to glue down the belt to the surface?
> Or having it well streched is a possibility?
It’s the bonding down of the counter belt that makes the whole thing better
than a conventional belt drive
T
Gluing a timing belt to an aluminum rail is really just a low-cost rack.
Rather than using a pinion you use "caterpillar" tank treads to engage the
track.
I would place the "tack" facing down so wood chips and dust does not
accumulate
On Sun, Apr 21, 2019 at 10:52 AM Leonardo Marsaglia
wrote:
>
>
> You could use a bunch of these mounted on the frame, spaced at intervals
> determined by stretchability of the belt;
>
> https://reprapworld.com/products/mechanical/timing_belts/aluminum_belt_clamp_gt2/
> Or machine them yourself?
This looks really nice too. I guess this should work pretty
> On Sun, 21 Apr 2019 at 15:17, Leonardo Marsaglia
> wrote:
>
>>
>>
>
>> I'm wondering if the belts are specially made for that system, because I
>> can't find (easily) any belt with equal teeths and valleys to engage them
>> perfectly.
>>
>
>
Apparently you're meant to use the T profile.
Not AT
> On 21 Apr 2019, at 13:39, Leonardo Marsaglia wrote:
>
> I'm worried about the streching of the belts under acceleration, do you
> think I should use a special kind of timing belt? Like kevlar belts to
> avoid stretching under accelerations from 0 speed or under changes of
> direction?
The
On Sun, 21 Apr 2019 at 15:17, Leonardo Marsaglia
wrote:
> Researching a little more, it seems the belt that's facing upwards is glued
> down to the support profile, so that eliminates the need of tensioning that
> one.
>
> I'm wondering if the belts are specially made for that system, because I
On Sunday 21 April 2019 08:39:28 Leonardo Marsaglia wrote:
> Thank you guys again for your support!
>
> Well, I'm now taking a look at the ServoBelt datasheets and it looks
> more than promising.
>
> I guess I can make a belt reduction from the servo to the little
> sprocket to gain torque. That
Researching a little more, it seems the belt that's facing upwards is glued
down to the support profile, so that eliminates the need of tensioning that
one.
I'm wondering if the belts are specially made for that system, because I
can't find (easily) any belt with equal teeths and valleys to
Thank you guys again for your support!
Well, I'm now taking a look at the ServoBelt datasheets and it looks more
than promising.
I guess I can make a belt reduction from the servo to the little sprocket
to gain torque. That was my original plan with the rack and pinion but this
seems to be much
Wow, 3 meters! Another way I've seen is to use a cable. There are
pulleys at each end and the cable forms a loop. In the simplest design a
motor powers on of the pulleys. The cable takes the price of a long timing
belt. I've seen kevlar cord used for a cord and some steel cable also.
In
On Saturday 20 April 2019 16:44:29 andy pugh wrote:
> On Sat, 20 Apr 2019 at 21:27, Leonardo Marsaglia
wrote:
> > I plan to use some chinese rack and pinions (MOD 2 with 30 teeth
> > pinions rotating at a max speed of 200 RPM) for the obvious reason
> > of the budget. But I can get hardened and
On Sat, 20 Apr 2019 at 23:39, Leonardo Marsaglia wrote:
> I miss the select and reply feature I had until a couple of years.
Yes, I was annoyed when they removed that.
> Do you think two 2.4 Nm motors with almost non reduction can handle the
> inertia the 250 kg gantry will generate?
Possibly
>
> If you click the three dots that appear at the bottom of the reply
> then you can edit, post inline, copy between messages etc
> (I use Gmail pretty much exclusively)
Ok, I just had to copy and set the copied text as "quote" because I can't
do it the easy way as you sugest Andy. I miss the
On Sat, 20 Apr 2019 at 22:03, Leonardo Marsaglia wrote:
> I'll try to answer both messages into one because I lack the quoting
> function here in gmail.
If you click the three dots that appear at the bottom of the reply
then you can edit, post inline, copy between messages etc
(I use Gmail
Thanks Andy and Chris for your quick response.
I'll try to answer both messages into one because I lack the quoting
function here in gmail.
I plan to reduce the servos of the Y axis about 10 to 1 at least. I would
love to use timing belts and pulleys but I preffer to avoid all the trouble
of
backlash is a big deal. Maybe not so much with wood routing as maybe you
don't care about 0.1 mm error.But think about a how a backlash in
the 10:1 reduction translated to linear motion. Every time the servo
motor changes direction the cutter stops moving until the backlash in the
system is
On Sat, 20 Apr 2019 at 21:27, Leonardo Marsaglia wrote:
> I plan to use some chinese rack and pinions (MOD 2 with 30 teeth pinions
> rotating at a max speed of 200 RPM) for the obvious reason of the budget.
> But I can get hardened and ground rack and pinions so I think that sounds
> pretty
Hello to all again!
I'm defining my router design after some months of inactivity. I already
defined my steel frame and purchased the iron to start building it. The
idea is to use the router mainly for wood and melamine boards. Eventually I
may use it for aluminum but that's not the main purpose
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