Here is a list of all the postings Gary Wooding has made in our forums. Click on a thread name to jump to the thread.
|Thread: Centec 2A riser block|
I made several batches of RBs. The 1st batch had the Centec logo machined into the side and hi-lighted with black paint, as shown in the first 3 photos. The subsequent batches had the brass labels shown in the last photo, but I fitted them only on the 1st of them. For the remainder, I supplied the badge and hammer-nails with instructions on how to fit them, but left the actual fitting to the buyer. You possibly have one of those. I fitted stainless dome nuts and thick machined washers to all my blocks, so if yours has them then it could be one of mine.
The 457mm length was as I ordered, but I had to clean them up and possibly lost a mm.
I got the alloy bar from Richard Austin Alloys in Coventry.
No problems have been reported about the VH's weight on the raising bar when slid in the forward position.
I don't think it matters at all if the female dovetail was a little on the large side. There has to be clearance otherwise you can't slide. The fingers push the male dovetail sideways so there will be a gap on the finger side, but none on the other.
The drawings I created for making the blocks were intended for my own use only, but I've had so many requests for them that I've put them in a PDF. They are not really of publishable quality but they are what I used, so they do the job. If you decide to redistribute them then please acknowledge their origin.
The PDF can be found **HERE**
Here are some photos of a few
Sorry Bill, the Domestic Authority has forbidden me to make any more.
I still have the drawings though.
I've made about 20+ blocks, mostly long ones, but 2 or 3 short ones. All were made of 6082T6 aluminium.
If you're considering making one then I can let you have some of the working drawings I did. If you intend to do any horizontal milling then I strongly recommend making a long one because the VH is very heavy, and once fitted on a long block, it doesn't need to be removed for the change over.
|Thread: Chosing a drill grinding attachment or machine|
Take a look at **THIS** It works fine for me, and at about £50 is difficult to fault.
|Thread: Tolerance for needle bearings?|
There are eight rollers - 4 on each side. I've made the seat semi-transparent to make them easier to see.
What are cam follower bearings and what sizes are available.
Incidentally, I intended to use two needle bearings to replace each of the four Delrin bearings that actually take the load - the Delrin ones are 20mm wide and the needle ones are 10mm.
Ian, I'm not convinced that two screwed rods would make the seat any more stable than the pairs of rollers that surround the uprights, as shown in the picture. Am I wrong?
I've removed the parts that obscured the view.
I originally used M12 Allthread, but it vibrated so much that I concluded it was too thin - hence M18.
I tried precisely that chairlift Neill, but apart from being rather unstable, it had two insurmountable problems:
1. In its collapsed position it was too high - the guy couldn't get on it.
2. It couldn't lift high enough.The seat of the wheelchair is 23" above floor level.
The part number of the bearings I've purchased is HK0910 (13x9x10).
I'm pretty much convinced that friction is the enemy here (comments are welcome). Would an Acme thread be any better than a standard metric? What size rollers would be more suitable, bearing in mind that bigger rollers increase the seat distance from the guide rails?
Hi Michael, I'm not interested in being right, I just want to make a device that works, so I'm open to all suggestions .
In order to reduce the overhang as much as possible I designed the roller assemblies to be symmetrical; all 13mm basic diameters with cheeks or flanges as guides. The "jockey" rollers don't actually do anything except help guide the seat. The axles were originally 8mm diameter. By "proper" bearings I assume you mean ball bearings. I thought of that but was advised that ball races with an OD of 13mm wouldn't withstand the expected forces - that's why I thought of needle rollers.
Unfortunately, increasing the diameter of the rollers increases the overhang of the seat relative to the upright guidance rails.
Here is the reason for the query. It's a Remap job to help a 75Kg paraplegic get himself up off the floor onto his wheelchair or bed etc. He has sufficient upper body strength to get himself onto something a couple of inches high, but no higher. The concept is a lift with a seat that is raised and lowered by means of a screwed rod that is rotated by a motor from an 18v cordless drill. The seat, which is only about 1" thick, is raised from the floor up to about 23".
The screwed rod is M18 Allthread, and the nut is brass. Although the motor should be able to lift the person up 23" in about 1 minute, it can't. We think there is too much friction. The original rollers were made of Delrin, but we think that they deform under load to create too much friction. We replaced them with brass, to no effect, so we thought to use needle roller bearings. Here are some pictures from the Fusion design.
Thanks for the information guys. That all makes sense. The outer race will not be supported - it will just roll along a flat tube where it will have to withstand a radial thrust of about 100Kg. I considered case hardening the axles, but in light of Duncan's statement am having second thoughts.
I have some small drawn cup needle roller bearings - 13mm OD and 9mm ID.
When turning the axles I decided to turn them initially to 9.05mm and then creep up to the final 9mm, but the bearing is a decidedly slack fit at 9.05mm. Is this as expected? Should I turn them to 9mm, or redo them to make a good fit?
|Thread: Tyres for bandsaw|
I've ordered the tape and will report back with the results.
|Thread: Why do I keep getting logged-off?|
I'm using only one device and this started to happen only a week or so ago.I'll treat it as an annoyance.then.
In the past few days I've been logged off this site about 5 times. Why?
Usually, my logon lasts for weeks, but this morning I not only had to logon again, but a couple of hours later I wanted to post something. After composing the post I was told I had to login again. I logged in and found my post had been deleted and had to re-compose it. Grrh.
|Thread: Tyres for bandsaw|
Thanks for the suggestions. Scott+Sargeant are far too pricey so I'm going to try Nathan's suggestion of self amalgamating tape.
I've inherited a Naerok bandsaw for wood, it looks exactly like the Clarke 360.. It hadn't been used for a number of years and the drive belt had stretched so I replaced it with a polyurethane one. When I tried sawing, it kept shedding the blade. I thought I'd fixed that and then one of the two tyres disintegrated. Further investigation suggests that there should be 3 tyres - one for each wheel, but now there is only one.
Can anybody suggest where I can get replacement tyres please?
|Thread: What mills have you had|
My first was a vertical slide on a Boxford BUD, but I now have a Centec 2B with the Mk3 VH and power-feed. I've fitted VFDs to both spindle and power-feed, a 3-axis Newel DRO, and a Raising block.
|Thread: Learning Fusion 360|
After about 14 years of using TurboCAD I enrolled for a free one day course about SolidWorks. I was sold. It was so much better than TCAD, but there was no way I could justify the astronomical price. And there was no concession for REMAP usage. Then, in 2016, I heard about F360, which appeared to be very similar in many ways.
I downloaded and tried the built-in tutorials but, without any good documentation, found progress slow and painful. F360 documentation leaves a lot to be desired.
I then discovered the series of videos by John Saunders **LINK** to be rather useful and learnt a lot. When his series started to concentrate on CNC I looked elsewhere and discovered the series by Lars Christensen **LINK** which I also found to be very useful. That's where I learnt how to do stress analysis.
I've found that I tend to make most progress from having to finish a personal project rather than by following tutorials. I then discovered the Autodesk Community of the Philippines **LINK** This was quite different. It's actually a series of 10 or so monthly challenges designed with the aim of awarding a certificate to those who register and complete the series. It's not necessary to register in order to see each challenge - I didn't. Each challenge is a bite-sized project designed to introduce one or two new concepts. If, like me, you don't register, you have to wait for the end of the month to see the challenge and it's solution, which is presented in a very clear manner, with each keypress fully described. Challenges from earlier years are a good source of information.
I've now switched to F360 for just about all my CAD work, but resort to TCAD for quick 2D drawings. F360 isn't very good for 2D drawings - it can create the normal orthographic drawings from 3D models, but 2D is not what it's all about.
Edited By Gary Wooding on 18/07/2019 17:14:10
Edited By Gary Wooding on 18/07/2019 17:15:19
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