Gerald, Have you given the width of the slide plate after machining the V rails. What I find is only the sawing dimensions given. Please educate me on this.

The sawn width of the plate was 100 mm. The drawing was given to my machinist and since he could not find the final dimensions (width) of the plate after machining, he had finished the plate to a 94 mm width. When we tried to put the rollers in today we found that even after making adjustments to the extreme with the ecentric busings the rollers would not fit into the plate.

The overcome this situ the easiest way out was to make new holes in the spider plate. We plugged the exisiting holes by screwing in bolts onto the existging holes and the grinded them flat. Then we increased the width between holes by 2 mm on all two sides. We were able to overcome the problem by doing this.

After doing this alteration we are in a situ where the motor mounting screws are hitting the spider bracket while moving. To overcome this we are planning to contersink the bolt which is clashing with the spider plate.

The ideal final width (after maching the V rails)of the plate should be around 90 mm. The ecentric busings will take in widths between 88mm and 93 mm according to our calculations.

Gauge plate is very exactly 100mm wide, and there is no need to machine it any narrower. Therefore, the finished size is 100mm (as originally supplied).

Then, for drilling the holes in the spider plate, according to drawing 1040430D, the dimension is given as (132) in brackets with a note "To suit slide and V-rollers". Maybe I should have made it clearer that dimensions in brackets are only a guide and must be checked against other parameters. In this case, the choice of V-roller will make a difference, and whether the gauge plate is 100mm or 4 inches.

The eccentric bushings are also used to get the z-axis perpendicular to the table.

I am concerned about collisions between your router (and bracket) with the z-axis rollers....?

I am using the rollers from supremebearings. Maybe their are dimensional differences between BWC and Supreme rollers.

The collision between router and rollers cannot be that difficult to overcome. The bolt head just has to be taken care of. Since we have come this far this minor thing cannot be a big issue.

Gerald,

There hasn't been a post in this thread in quite some time so I thought I'd break the silence.

I have been studying this section and I'm missing something in the purpose of some of the machining to the guage plate.

Can I assume that most of the pairs of holes are for a range of adjustment for the attachment of a router bracket? It surely doesn't take that many cap screws to attach the tube. I also don't understand the purposes for the 6mm dowel holes or the 10.5mm hole for the drawbolt.

... and I apologize if this is obvious but I did search for the answer before I asked.

Marc,

As many holes as possible must be used for screws to form a very tight sandwich between the plate and tube. (To stiffen a phone directory you need to clamp the pages together tightly). When mounting a Fimec or HSD spindle, 4 of those holes are bored threadless right through, but all the rest are "filled" with screws.

The 2 dowel holes and drawbolt are what I used in this thread (last 2 pics in post # 16) to have those routers interchangeable. It allows a "quick-change" bracket needing only one bolt.

Gerald what is the down side to using mild steel for the Z plate? when I was putting my Z slide together I noticed the spider plate performs like a spring because of the way it's bent, you can actually put some pressure on the guide rollers against the plate and it doesn't seem to interfer with anything. When there is some wear the spring action will take care of it, or so it seems to me. What are the thoughts on this, anyone?

I think mild steel will be okay if you can find a very straight piece. It can be replaced if it does wear out.

Zslide
 

I used 6" channel on my table, and I am not sure which of the slide plate and tubes I should use for my table.
Should I go with the 10" slide, or would there be any advatage in making it longer since I didn't use 7 or 8 inch channel?

On plan drawing 10 40 330 there is a metric option on the 10" slide that is about 2-3/4" longer. So I wasn't certain which one of those to go by, the short or long one.

I guess it really depends on what you plan to cut. If you know you will only cut 3/4" sheet goods, there is no need for a longer slide. On the other hand, if you think you might like to do some 3D work, the ability to go higher will definitely come in handy.

I built the Classic MM and I didn't realize that in the uppermost position, the bottom of my bit would only be a few inches from the top of the table. That's my fault because Gerald was very clear from the beginning that the MM will carve 3-4 inches. I guess it just didn't sink in. No big deal in my case because I don't expect to cut anything thicker than 1" or so.

Hope that helps.

Well said Doug.

There is no harm in building the longer z-slide - it might increase the re-sale value one day :)

On a serious note, I added the longer versions as options so that folk could see what is involved when they kept on asking "How can we extend the z-axis?" Hopefully I have left enough warnings around that things will flex a lot more in this case. But Ed, with your 6" channels on the table sides, you can can only use a short end of the slide, the longer bit sticking out the top doesn't cause you any more flex.

Gerald,
If you build the longer Z slide, do you need taller side rail to take full advantage of it? Or does it just allow you to retract the Z farther up than the shorter one? :confused:

Good question Heath,

1. The longer z-slide needs taller "side rails" before you get any advantage out of it. The gantry must be higher above the table top and the longer slide lets you "reach" further down. (Downside is more flex when cutting sheets lying further below the gantry.)

2. For retracting the router further up, the extra pair of rollers (and longer rack) allow you to do that without actually lengthening the z-slide. It is more a case of pulling a long cutter out of a workpiece. (Downside is that your dust system might not go up that far, and the difficulty of aligning 6 rollers)

Gerald,
Would it be practical to make the longer Z slide with the standard side rails, and later if the need came about , add another C channel to the sides to gain the extra clearance? Or would you need to replace the side channels with taller ones. I am thinking stiffness and rigidity, not ascetics.

You could put a "spacer" on top of the standard side rails to lift the gantry higher off the table (maybe a square box tube). At this point one is not too worried about the stiffness of the side rails because your biggest headache is the z-slide losing its stiffness. You would only do this for cutting lightweight material anyway.

Having done some more assembly on the Y-car today I noticed one small item that may need a mod. Once the gas strut (Gabriel Gaslift mod 4047 - 257mm stroke) is in place and the Z slide moves up to the max up position, the pinion is on the very end of the rack and when the Z slide is moved to the lowest position, there is still about 15mm of rack exposed at the top.

I know this will not affect the performance as I am getting the full 250mm stroke (actually slightly more) but it might be worth considering either moving the rack slightly lower on the slide or making the offset on the upper strut bracket longer. If the offset is made longer the slide will be able to plunge a little lower but will also sit lower when fully up.

Alan, I have been hacking at the drawings today (you can see a lot of posts disappear from this thread as I tackle the issues), and the whole z-slide/spring has me pulling my hair out. Can you see some common ground between what you are getting today and this thread: http://www.mechmate.com/forums/showthread.php?t=755?

Gerald, most of that thread is redundant as stated, its late now but I will do a more detailed assesment of my situation tomorrow and report back with accurate numbers.

Sorry it took so long to get back on this but I took the family out to lunch at Dassiesfontein, been spending too much time in the garage and the mood was getting testy...

Here are some pics of the situation, as I said, it does not affect the performance but the pinion does get very close to the end of the rack in the fully up position

Attachment 1662
pinion on end of rack when slide fully up

Attachment 1663
rack still exposed when slide fully down

Attachment 1664
distance from lowest point on spider to bottom of slide when fully up - 54mm (this shows that the middle wheels could be positioned a little lower if required)

Attachment 1665
distance from lowest point of spider to bottom of slide when fully down - 200mm. (photo has parallex error)

Ah Dassiesfontein, one of those gems that 80% of tourists to this country drive past and don't bother to stop.

Alan, you couldn't have made it clearer than that!

If that was mine, I would like:
a. the rack to be longer to the bottom so that,
b. the slide could go further up until it nearly gets to the center of the middle rollers, to achieve this I would
c. Mount the upper strut anchor bracket lower down on the rect. tube., because
d. I would be happy to lose some of that 200mm because that puts the collet against the table.

Does that make sense?

That sounds like a good plan, I think I have some spare rack I can cut and drill to suit...watch this space :)

Ah Dassiesfontein :eek:
Woawy woaw, now that is a very nice place to go indeed. Some nice photos to look at from that web site.
Anyone in your “neck of the woods” in need of a “talented” :rolleyes: woodworker for a short trade-guild exchange period.
Very nice place to be !!
Robert ;)

Alan, I found the "missing" dimension ...... racks needs to be 300 long and not 280. (Well, you did get 250 stroke, so you can't really complain ;)). I see that Kobus sommer stuck all his leftover rack behind the slide - that's not a bad idea either!
http://www.mechmate.com/forums/showt...&postcount=159

I had the extra rack, so just used it...Boer maak 'n Plan...

Gerald what is the substitute for gauge plate?

Phoned all the steel supplyers in my area and walked straight into a wall.
Some of them don`t know the product even tried P.E. but no help.

100 x 6 mild steel flate bar, provided that it is straight over that short length. The life will be a bit shorter that that of gauge plate. You might 5 years instead of 10 years. :)

Promise you that you will get gauge plate in PE. That town is vrot with toolmakers for the motor industry. Gauge plate for a toolroom is like chipboard for a cabinetmaker - it is a staple diet.

Edit to add:
Sanderson Steel, 041 453 9645, have stock, R249.40 excl.

Rack and upper strut mount modified:

a) made rack longer - 315mm
b) placed first mounting hole 45mm from top end of rack
c) moved upper strut bracket down by 15mm

Attachment 1667 Attachment 1668
full travel with equal amount of rack to spare

Attachment 1669 Attachment 1670
slide almost in centre of middle pair of wheels 67mm above spider, slide at lowest point 187mm below spider = 254mm of travel (10")

That looks better ;)

If it wasn't for the limitation imposed by the gas spring, there would be a lot more travel offered by the rack.

Can't stop admiring the photography!

The Z-slide tube, drg 10 40 360 ask for a 50x25x 3 wall thickness. I am having difficulties in sourcing the 3mm wall, cut to size off 490+10. My supplier can only sell it to me in 6 meter lengths.
Gerald, will the same profile with 2mm wall have to much twist in it.( or maybe not stiff enougth) ?
I saw a photo somewhere of a bend up lipped 'u'. That could work?

Lex, there is a big difference in stiffness/strength between 2mm and 3mm wall in this case. You also need to tap threads into it. If you really must take 6 meters, use the rest in the underside of the table.

I'm wondering how folks have fabricated the Z slide.

I've checked into tool steel. Sort of expensive, about $40 for a 1/4" x 4" x 18", but not out of the question. Wouldn't want to mess up a piece, though.

I see comments that tool steel can't be milled, must be ground. Too short to use the skate. I see that Gerald used the table saw. What have folks done that you feel worked well?

I see that some folks have used a "flat" piece of mild steel. Have you used the skate? Did you have it hardened?

I would appreciate any input on what has worked and what hasn't worked for making this piece.

Regards,
John

Not true - it mills, drills, taps beautifully. Tougher than mild steel, but no problems with normal cutting tools in standard mill or drill press or hand tapping or filing or sanding.

John,
Some have used mild steel and the skate, some have used mild steel and the superior rails, (which is the way I am planning on going) and others have used the tool steel and used the skate ( by tack welding some donor angle iron to extend the tool plate so the skate would work) this was done by a member who is no longer around though.

Mine (tool steel/gauge plate) were bevelled on a milling machine and finished with draw filing and emery (sand) paper.

Post #3, in this thread, quoted below, is where I picked up the idea that it couldn't be milled. Glad to hear I was mistaken.

If you welded on a donor strip, wouldn't you mess up the hardening?

I don't have a mill. Would grinding it on the table saw with an abrasive blade work? Or, do I need to get someone to mill it for me?

Regards,
John

John, he changed his mind on the machineability in his next post.

I did grind a sample on a table saw - it does work. The biggest issue is to decide whether you are happy to do that to your saw and whether you can get a grind disk that is suitable.

Very helpful, thanks.

So, Gerald, with the draw file, were you just soothing the milled bevel? If more than that, how did you control the angle of the draw file to prevent over cutting into the bevel. It seems to me that the most important dimension of the slide would be the distance from one bevel to the other as seen by the V-rollers of the spider. So if there was a gouge or raised place in one of the bevels, this equi-distance would be affected and cause the slide to move slightly left or right as it is traverses up and down through the spider. And since the spindle is on the end of the Z slide, this unwanted motion would be amplified.

Am I just worrying over nothing here?

Regards,
John

The draw filing was only to "sooth" as you say (maybe you meant smooth). Only to remove the small tool chatter marks left by my milling guy - I didn't tell him I wanted it smooth.

Thanks Gerald, yes I meant smooth. And iespell checker didn't help. I guess there's no help for a confused brain.:confused:

Regards,
John

chosing flat stock for Z slide
 

Hi all
Is it a big difference for using O1 Tool Steel, Hardness: Rockwell B85-B96, Width tolerance +0.005" from McMaster-Carr pn 9516K91 (www.mcmaster.com/#9516k91/=19aq5f) compared to mentioned here Starrett precision ground oil hardening stock (hardness: 230 Br, Width tolerance is +0.0001") from Wttool.com? For me 9516K91+delivery will cost some $30 less...

Also another case - will A2 tool steel plate 0.3125"thick go instead of 0,25"?

And third possible case: as per drowings the plate's length is 18" or 500mm because of standart stock sizes, but how short it may actually be for Z stroke 250mm?

Mild Steel is about Rockwell B70 (Brinell 120)
O1 Tool steel: Rockwell B90 (Brinell 185)
A2 tool steel plate : Rockwell B95 (Brinell 210)
Starrett precision ground oil hardening stock Rockwell B98 (Brinell 230)

You will have to decide if you have the tools to cut the steel.

Plate 0,3125" thick can be used instead of 0,25"

The plate's length is also decided by the mounting of the gear rack. There is very little that you could reduce the length. You can cut away the side opposite to the rack if you want to reduce mass.